Pathology, Lecture 10, Neoplasia

NEOPLASIA (2010-2011)

Dr.H.M.Zahawi,FRC.Path

OBJECTIVES Definitions of terms used in neoplasia Nomenclature of tumors Characteristics of benign & malignant

tumors Routes of metastasis Epidemiology of CANCER The molecular basis of neoplasia Carcinogenesis Tumor immunity The clinical effects of tumors Tumor grading and staging The laboratory diagnosis of neoplasia

General terms used :

Neoplasm = New growth of cells producing a mass

Benign neoplasm = Limited new growth without invasion or spread

Malignant neoplasm = invasive growth that also spreads Carcinoma : Malignant tumor of epithelial cells Sarcoma : Malignant tumor of connective tissue

cells Lymphoma

Cancer is a general term for all malignant growths of whatever type

Tumor may be used instead of neoplasm but the term is not accurate

Oncology : study of cancer in all its aspects

NEOPLASM :

Abnormal mass of tissue, the growth of which EXCEEDS and is UNCOORDINATED with that of of the normal tissues, and PERSISTS in the same manner even AFTER CESSATION of the stimulus which produced the change

A neoplasm develops from a single transformed cell !!!

Features of transformed cells :

Persistent & useless Uncontrolled growth * Immortal Transplantable

This cell may arise from : Endoderm Mesoderm Ectoderm

Epithelial cells may arise from any of the above Connective tissue is from

mesoderm

Classification of Tumors :

Cell of origin Behavior of tumor : Benign or

malignant Appearance of the tumor:

Solid/cystic Degree of differentiation

Structure of neoplasms : - Parenchymal cell - Stromal ( supporting cell )

Degree & type of stromal cells may contribute to the appearance of tumors

If there is stromal proliferation hardness of the tumor Scirrhous tumor Desmoplasia

e.g.carcinoma of breast, pancreas…..etc

If there is lack of many stromal cells, the tumor may be soft or cystic.

This feature may be included in the name of the tumor..e.g… Cystadenoma of ovary Poorly differentiated

cystadenocarcinoma of ovary Moderately differentiated scirrhous carcinoma of breast

Serous cystadenoma of ovary

Scirrhous Carcinoma of breast

Benign Epithelial tumors :

Adenoma - glandular epithelium tumor often producing a secretion e.g. (mucin) which may be intraepithelial or intraluminal

Papilloma – epithelial tumor forming finger like projections from epithelial surface with a connective tissue core

Polyp – a tumor projecting from the mucosal surface of a hollow organ

Structure of Polyp

Malignant epithelial tumor : Carcinoma

Squamous cell carcinoma e.g. skin,mouth

cervix, bronchus….etc

Adenocarcinoma from glandular origin, e.g.G.I.T.,endometrium,breast, kidney, thyroid…..etc

Connective tissue cell origin :

Benign :Named by tissue of origin with

attachedsuffix – omae.g. fibroma, lipoma, chondroma…etc

Not all endings (– oma) are benign tumors e.g. : granuloma,lymphoma, hamartoma, choristoma…etc

Malignant connective tissue tumors:

SARCOMA : Prefix (origin)+ suffix (sarcoma) e.g. Osteosarcoma, liposarcoma,

angiosarcoma leiomyosarcoma,

rhabdomyosarcoma…

Some tumors are MIXED !!!

Mixed Tumors :

Tumors derived from a single germ cell layer that differentiates into more than one cell type.

e.g. mixed tumor of salivary gland, Fibroadenoma of breast

OR : Teratomas – made of a variety of

parenchymal cell types that derive from more than one germ cell layer formed by totipotent cells that are able to form ectoderm, endoderm & mesoderm

TERATOMA : May be benign or malignant

depending on structure, site, age, sex ….

Contain skin ,sebaceous & mucus glands,hair,cartilage, bone, respiratory epithelium, glial tissue…..etc.

Usual location is ovary or testes

Tumors of primitive fetal origin :

Blastoma : from immature tissue May arise in kidney, liver, retina…etc e.g. Retinoblastoma

The great majority of these tumors are malignant & occur in infants & children

Some tumors have names that do not conform with general rules :

Melanomas arise from nevus cells Seminomas arise from testicular germ

cells Lymphomas arise from lymph nodes Some tumors are named eponymously e.g. Hodgkins disease, Wilm’s

tumor….etc

Note : See table on page 176

Some ‘tumors’ are NOT true neoplasms

Hamartoma : Tumor like malformation in which

there is abnormal mixing of normal

components of the organ ,either in the form of change

in quantity or arrangement of tissue elements.

e.g. Lung Hamartoma.

Choristoma :

Different types of tissue, ectopic to the region.

e.g. Meckle’s Diverticulum, Salivary tissue in LN

Both are present at birth & do not become

malignant .

How do benign & malignant tumors differ?

Differentiation & anaplasia Rate of growth Presence of capsule Local invasion Distant metastases

Benign versus malignant tumors

- This indicates the degree of resemblance of the tumor cell to its cell of origin,

functionally & morphologically. e.g –

Cells of a lipoma may look exactly like normal fat cells.

1- Differentiation:

LIPOMA LIPOSARCOMA

Features of differentiation include : Epithelial cells :

- formation of glands - formation of keratin - formation of secretion…etc

Connective tissue cells : - formation of osteoid - presence of lipoblasts - Striations in tumors of

skeletal muscle….etc

Well formed glandular architecture

No acini ! SIGNET CELLS

- When a tumor cell loses its differentiation

it gradually gains features of DYSPLASIA

It is a process of gradual loss of differentiation

It is an abnormal growth which may precede malignancy

Complete loss of differentiation

ANAPLASIA

Cytological Features of Dysplasia

Increased nuclear size , N/C ratio Variation in nuclear & cell size :

PLEOMORPHISM Loss of differentiating features Increased nuclear DNA content

HYPERCHROMATISM

Features of dysplasia (continued) :-

Nucleoli :Prominent, sometimes multiple

Mitotic figures : Increased Abnormal mitoses: may be present Loss of polarity : in an epithelial

surface

Severe Dysplasia/ Anaplasia

Intraepithelial Neoplasia

Dysplasia involving an epithelial surface

Low grade & High grade High grade dysplasia ,limited by

epithelial basement membrane CARCINOMA IN SITU

Intraepithelial Neoplasia

NOTE :

Not all dysplasias progress to higher grade or carcinoma in situ.

Not all carcinoma in situ progress to invasive CA

Some cases of dysplasia can regress

Rate of growth usually correlates with level of differentiation May be rapid in some benign tumors Some tumors may shrink in size Some malignant tumors may outgrow their blood supply

2- Rate of growth

Some tumor growths are semicontroled :

HORMONE DEPENDENCE : This is through presence of receptors on

surface - Breast CA

- Thyroid CA - Prostatic CA

Benign tumors frequently have a capsule

Malignant tumors progressively invade & destroy surrounding tissue e.g.Breast cancer infiltrating skin Basal cell carcinoma face infiltrating nerve *Second most important feature

distinguishing malignant tumors

3- Local invasion & Encapsulation

Spread of malignant tumors to distant sites not contigious with the main tumor

Most important in diagnosing malignancy

All tumors can potentially metastasize except BASAL CELL CARCINOMA

Metastasis is often proportionate to the size and differentiation of the primary tumor

4- Metastasis :

Routes of metastases :

Lymphatics Blood vessels Seeding within body cavities/ Transcoelomic Spread

1- Lymphatic Spread : More characteristic in Carcinoma Spread follows the anatomical route of

drainage unless skip “metastases” e.g. Breast cancer in left upper upper quadrant Left axillary L.N. In medial quadrant internal mammary chain supraclavicular & infraclavicular Lung Ca - Peribronchial tracheobronchial LNs hilar LNs

IMPORTANT IN SURGICAL RESECTION :

Sentinal Lymph Node : First lymph node in the pathway of a primary tumor. Usually outlined by dye

Not all enlarged L.N.s indicate metastases

e.g. Reactive hyperplasia Histiocytic infiltrate in sinuses

2- Hematogenous spread :

Usually venous first following anatomical drainage : Lung & Liver More characteristic of Sarcoma ,but may in occur in later stages of carcinoma Certain carcinomas invade veins early

RENAL Carcinoma renal vein IVC Hepatocellular Carcinoma Portal &Hepatic

v.

3- Transcoelomic spread:

Within peritoneal or pleural cavity e.g.: CA of upper lobe of lung to lower lobe CA of stomach to ovary CA of ovary tends to spread widely through peritoneal surface CA of colon across peritoneum to S.I.& colon

BENIGN vs MALIGNANT

Anaplastic High mitotic index Rapid growth Infiltrative growth without capsule Invasion Metastases

Well-differentiated Low mitotic index Slow Growth With capsule No invasion No metastases

Summary : Differences between benign & malignant neoplasms

EPIDEMIOLOGY of CANCER

2006 Estimated US Cancer Cases*

*Excludes basal and squamous cell skin cancers and in situ carcinomas except urinary bladder.Source: American Cancer Society, 2006.

Men720,280

Women679,510

31% Breast

12% Lung & bronchus

11% Colon & rectum

6% Uterine corpus

4% Non-Hodgkin lymphoma

4% Melanoma of skin

3% Thyroid

3% Ovary

2% Urinary bladder

2% Pancreas

22% All Other Sites

Prostate 33%

Lung & bronchus 13%

Colon & rectum 10%

Urinary bladder 6%

Melanoma of skin 5%

Non-Hodgkin4% lymphoma

Kidney 3%

Oral cavity 3%

Leukemia 3%

Pancreas 2%

All Other Sites 18%

2006 Estimated US Cancer Deaths*

Men291,270

Women273,560

26% Lung & bronchus

15% Breast

10% Colon & rectum

6% Pancreas

6% Ovary

4% Leukemia

3% Non-Hodgkin lymphoma

3% Uterine corpus

2% Multiple myeloma

2% Brain/CNS

23% All other sites

Lung & bronchus 31%

Colon & rectum 10%

Prostate 9%

Pancreas 6%

Leukemia 4%

Liver & intrahepatic 4%bile duct

Esophagus 4%

Non-Hodgkin 3% lymphoma

Urinary bladder 3%

Kidney 3%

All other sites 23%

Incidence may be related to ethnic &geographic differences in community :

Nasopharyngeal CA Cervical CA & Cancer of the penis Burkitt Lymphoma Multiple myeloma Chronic lymphocytic leukemia

Genetic polymorphism is responsible for :

Individual predisposition to disease

Individual response to environmental

agents

Individual response to drugs

FACTORS WHICH MAY PLAY A ROLE IN THE INCIDENCE OF CANCER INCLUDE :

1- Geographic location :

Gastric CA -- High in Japan Skin CA------ High in New Zealand Hepatocellular CA --- High in

Africa,China Breast CA ---- High in USA Prostatic CA ---- High in USA Colorectal CA ----High in USA Nasopharyngeal CA--- Far East Burkitt Lymphoma ----- Africa

CANCERS common in JORDAN include :

Lung CA Colorectal CA } MALES Prostate CA

--------------------------------------------- Breast CA Colorectal CA } FEMALES Lung CA

Lymphomas are also common

2- Environment :

Diet Occupation Sunlight Personal habits

3- Age : In general , cancer incidence ≈ AGE However , certain cancers occur more in children

Acute Leukemia Some Lymphoma Some CNS Tumors Bone &soft tissue Sarcomas

4- Heredity : 5-10% of tumors

Inherited Cancer Syndromes : Presence of defined genetic

abnormality, usually AD, often specific phenotype

e.g. APC gene : Familial Adenomatous Polyposis Coli MEN1 & RET genes : MEN syndrome NF1 & NF2 genes : Neurofibromatosis RB gene : Retinoblastoma

Familial cancers : No specific phenotype & multifactorial Family members have higher incidence to common

cancers - CA of COLON

- CA of BREAST - CA of OVARY

Younger age groups, multiple or bilateral, two or more family members are affected.

Some linked to inheritance of mutant genes e.g. BRCA-1 & BRCA-2

AR syndromes of DNA Repair :

Chromosomal & DNA instability Best example :

XERODERMA PIGMENTOSUM

5- Acquired Preneoplastic Syndromes These are associated with increased risk for CA

and most are related to rapid or abnormal cell proliferation .

1- Endometrial Hyperplasia & carcinoma 2- Cervical Dysplasia & Cervical CA Bronchial dysplasia & lung CA 3- Liver Cirrhosis & Hepatocellular

Acquired preneoplastic syndromes (continued)

4- Chronic healing process

5- Ulcerative Colitis & Colorectal CA 6- Villous Adenoma & Colorectal CA7- Leukoplakia & Squamous cell CA

MOLECULAR BASIS OF CANCER

Neoplasms arise from a single clone of cells :

Group of cells produced from a single ancestral cell by repeated cellular replication.

Thus they can be said to form a single "clone".

MONOCLONAL

Principles :

Tumors arise from clonal growth of cells that have developed mutations in four classes of genes :

Growth promoting proto-oncogenes Growth inhibiting tumor suppressor genes Genes regulating apoptosis Genes involved in DNA repair

More than one mutations in above result in abnormal growth of cells

Carcinogenesis is a MULTISTEP PROCESS !

Multistep Carcinogenesis :

Steps in Neoplastic Transformation :

1-Non lethal damage TRANSFORMATION 2-Cell Proliferation : initially Polyclonal MONOCLONAL CELLS

3-Genetic instability of malignant phenotype

cells with diverse features progression of tumor INVASION & METASTASES

Heterozygous X-linked marker:

G6PD isoenzyme. In females

heterozygous for G6PD, normal tissues contain two populations of cells whereas their neoplasms are homozygous for one isoenzyme

Monoclonal proliferation

Clinical Examples :

Chronic myeloid leukemia (CML): Philadelphia Chromosome

(9:22 ) Multiple Myeloma single immuno-

globulin specific for the tumor. T&B cell lymphomas : specific gene

rearrangement

Tumor Progression :

This is the stepwise accumulation of

mutations resulting in increasing features of malignancy.

GENES IN NEOPLASTIC TRANSFORMATION

Genes in Neoplastic Transformation:

Outline of Gene Action :

Proto-oncogenes

Normal genes whose products (Oncoproteins) promote cell growth

Oncogenes are mutant versions of proto-

oncogenes that function autonomously without normal signals

Arise from mutant proto-oncogenes They are dominant genes. They include :

Growth factors Cell surface receptors Signal transduction proteins Nuclear transcription factors Cell cycle proteins Inhibitors of apoptosis

1-Genes coding for growth : Classified by site of action

1-Oncogenes coding Growth Factors

Normal Cell growth is stimulated by GF Platelet derived growth factor (PDGF)

seen in glioblastomas Fibroblast growth factor(FGF)-stomach

CA & melanoma……etc Transforming Growth Factor (TGF-)in

sarcomas Products of other oncogens (e.g.RAS)

may cause over expression of GF

2-Oncogenes coding Growth Factor Receptors

GF integrate with membrane receptors tyrosine kinase activity nucleus

Mutant receptor continuous signals even in the absence of GF…..OR

Normal but overexpressed hypersensitive to GF

Epidermal GF receptor family: ERBB1 in 80% of sq.CA lung ERBB2 ( HER 2 NEU) in 25-30% of

breast & ovarian CA --- Increase = POOR PROGNOSIS

3- Oncogenes in Signal Transduction:

RAS & non receptor ABL RAS action:

GDP GTP proliferation

Mutations in GAPs(NF1):Neurofibromatosis Commonest oncogen mutation Point mutations in codon 12, 13 are present in 30% of cancers, specially CA pancreas

&Colon

Active RAS

GTPase activity by (GAP)

Action of ABL : Non receptor associated tyrosine kinase signal transmission

Normal ABL is located in nucleus where it promotes apoptosis

Chronic myeloid leukemia : Mutation 9:22 translocation BCR- ABL gene This new gene is retained in

cytoplasm where it has tyrosine kinase activity cell proliferation

New action is Proliferation +No Apoptosis

4-Nuclear Transcription Factors : DNA transcription regulated by genes

e.g. MYC*, JUN, FOS….etc. In normal :MYC protein + DNA

Activation of Cyclin Dependant Kinases ( CDK’s)

initiation of cell cycle MYC MYC mutation sustained activation Examples :

Dysregulation of MYC present in Burkitt’s lymphoma (t8:14)

Breast ,colon, lung CA & neuroblastoma

5- Cyclins & Cyclin Dependant – Kinases regulate Cell Cycle phases

Family of proteins that control entry of the cells at specific stages of cell cycle

( D, E, A, B….etc.) Level of a specific cyclin increases at a

specific stage, then decreases rapidly after the cell departs that stage

Function by phosphorylating certain proteins ( e.g.RB protein)

Cyclins bind to CDKs, activating them

G2

(Labile cells)G0

(Stable cells)

(Permenant cells)

G0

G1S

M

CELL CYCLE PHASES

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Two important groups :

- Cyclin D family CDK4 & CDK6 at G1 S phase checkpoint - Cyclin B-CDK1 activate G2 M

transition

Activity of CDK/ Cyclin regulated by CDK inhibitors

Non selective wide inhibition : p21, p27 and p57 Selective effect on cyclinD/CDK4 &

cyclinD/CDK6 : p15, p16, p18, and p19

Cyclin/CDK/RB function

Loss of normal cell cycle control is central to malignant transformation& at least one of the following is

mutated in most human cancers : - Cyclin D - CDK 2, CDK 4, CDK 6 - CDK inhibitors - RB

Mutations that disregulate activity of cyclins & CDKs → cell proliferation

Examples : Cyclin D is overexpressed in breast,

liver, & esophageal cancers Amplification of CDK4 gene present

in melanoma, sarcomas, glioblastoma

Growth inhibitory pathway by: * Regulate cell cycle : Rb gene * Regulate cycle & apoptosis: P 53

* Block GF signals: TGF- * APC regulates -catenin

Cancer suppressor genes are recessive genes which may be lost in familial or sporadic cases.

2- Cancer Suppressor Genes:-

1- RB gene :

First studied in Retinoblastoma: Called RB gene Both copies of gene must be lost for neoplastic transformation to occur This is called loss of heterozygosity

Retinoblastoma :

Autosomal dominant hereditary disease May be sporadic In familial, patients carry one mutation in

their genome No tumor develops unless two alleles in 13q14 become mutant (two hit theory) ↑incidence of bilateral Retinoblastoma

and ↑ osteosarcoma

Inheritance of Retinoblastoma

Mode of action of RB gene:

RB exists in active nonphosphorylated & inactive phosphorylated forms. Active RB binds to transcription factors (E2F) NO TRANSCRIPTION CyclinD/CDK4, and cyclinE/CDK2

phosphorylate RB. Inactive RB releases transcription factor E2F TRANSCRIPTION (G1 S phase ) Many oncogenic DNA viruses may act

similarly by inactivating RB

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2- P 53 70% of tumors show homozygous loss of p53 p53 is a negative regulator of cell cycle,

present in low levels with short half life MDM2 protein which targets it for

destruction Called ‘Guardian of the Genome’ OR

(Policeman) preventing genetically damaged cells from progressing through new cycle.

Mode of activation & action :

P53 senses DNA damage through various sensors e.g. ATM protein

P53 is activated by anoxia, or DNA damage and accumulates in cell with long half life after release of MDM2

Activated p53→ Transcription of CDKI(p21) → cell cycle

arrest at G1 Transcription of GADD45 ( repair gene) p53 is a regulator of apoptosis

More time for repair Normal Failed repair Apoptosis or

Senescence(permanent cell cycle arrest)

Fixed mutation NEOPLASIA

Action of p53

P53 may show the following :

Acquired mutation in many cancers e.g. colon, breast, lung , leukemia…etc Inherited mutation in Li - Fraumeni S. sarcoma, leukemia, breast carcinom and gliomas ….. etc May be blocked by some DNA viruses producing viral induced cancers

3- TGF-

Antiproliferative activity: - regulation of RB pathway at G1 by action on some cyclins & CDKs - blocks GF signals

Mutational inactivation of TGF- components seen in 100% of pancreatic carcinoma & the majority of colonic CA

4- APC gene

Cytoplasmic protein , acts as an adhesion molecule by regulating level of

-catenin in cytoplasm* APC--- -catenin --- E-Cadherin Result intercellular adhesion* Mutant APC -- -catenin nucleus Result stimulates proliferation

Individuals with inherited one mutant allele of APC develop 100s to 1000s of adenomatous polyps in their 2nd.-3rd.decade of life

Additional mutations colonic carcinoma

100% risk in familial polyposis coli 70-80% of sporadic colonic

carcinoma show mutant APC

Mutations in genes involved in programmed

cell death which regulate mitochondrial permeability promoting or suppressing apoptosis.

BAX, BAK promote permeability BCL-2 , BCL-XL inhibit permeability BH3-only protein regulates the ballance

BCL-2 prevents apoptosis, prolonging life. Activated by translocation (18:14) Follicular B cell Lymphoma

3- Evasion of Apoptosis :

These are specialized structures at the end of chromosomes which are shortened after each division and may play a role in determining the life of individual cells. Shortening is prevented by TELOMERASE Active in stem cells, not in somatic cells Majority of cancers telomerase

4-Limitless replication potential(Telomeres)

Repair mutations in other genes Persons with inherited mutations in these genes are at ↑ risk for cancer These include :

1- Nucleotide excision repair genes Damage by U-V light . Defective in Xeroderma Pigmentosum Damage by ionizing radiation Drugs e.g. nitrogen mustard

5- Genomic instability due to defective DNA Repair Genes

Repair genes (continued)

2-Mismatch repair genes : These repair errors in pairing of nucleotides during cell division

e.g. G+T instead of A+T ( HNPCC).(Hereditary Nonpolyposis Colonic Ca.)

Repair genes ( continued) :

3- BRCA -1 & BRCA-2 80% familial breast cancer & ovarian

CA BRCA –2 in breast CA in both sexes, e.g: prostate,ovary, pancreas,

stomach CA

Rarely inactivated in sporadic cases.

Tumors remain small or in situ ( <1-2mm.diameter) without angiogenesis

Angiogenesis ≈ Antiangiogenesis Angiogenic Switch Controlled by hypoxia which induces angiogenic factors by tumor cells Hypoxia-Induced Factor(HIF-1) VEGF RAS mutation VEGF Proteases from tumor or stroma VEGF

6- Development of Sustained Angiogenesis :

Anti- Angiogenesis :

VHL protein can destroy HIF-1 No VEGF so VHL acts as tumor suppressor

Germ line mutation of VHL hereditary renal CA , hemangiomas in CNS……etc

Anti-angiogenic factors : e.g. P53 antiangiogenic thrombospondin Inactivation of P53 angiogenesis - vascular density = Poor prognosis

Tumors may generate clones with different phenotypic features, accumulate mutations, leading to a more aggressive nature e.g.

Non antigenic growth , Increase rate of growth,

Invasion, Metastases …etc Rate of generation of these clones

differs in individual tumors e.g. Osteosarcoma versus Basal Cell Carcinoma

7- Ability to invade & metastasize

Metastatic Pathway:

Metastases occurs in two phases :

1- Invasion :

Loosening of intercellular junctions Attachment Degradation of ECM Migration

2- Vascular dissemination

1- Mechanism of invasion of ECM :

1- Detachment of tumor cells Inactivation of E-Cadherin OR activation of catenin detachment of tumor cells - Loss of function E-Cadherin in many CAs -2- Degradation of ECM by proteases :e.g. Matrix Metalloproteinase (MMPs) Cathepsin D Type IV collagenase

- Result of digestion of ECM Cleavage products of matrix have chemotactic activity for more tumor cells

3- Attachment of tumor cells to matrix components by laminin & integrin receptors to basement membrane & ECM

4- Migration of tumor cells : Tumor derived cytokines e.g. Autocrine motility factor

2- Vascular dissemination : 1- Invasion of the circulation :

Adhesion to endothelium retraction ofendothelium vessel

2- Attack by NK cells, some escape by formation of a thrombus3- Escape from circulation :

Adhesion to endothelium retraction of endothelium escape to tissue

WHAT INFLUENCES SITE OF METASTASES ?

Anatomical Location Complimentary adhesion molecule between tumor cells & target

organs Chemoatractants liberated by

target organs Protease inhibitors present in

certain tissues

Examples of Tropism ( Homing )

Prostatic Carcinoma Bone Lung Carcinoma Adrenals & Brain Neuroblastoma Liver & Bone Less common sites of metastases

include skin,muscle thyroid,breast….etc.

Spleen , Cartilage , Heart are almost never involved by metastatic tumours.

Each cancer must result from accumulation of multiple mutations,

in many genes including those in apoptosis & senescence

EXAMPLE :

Steps in carcinogenesis may be followed genetically & histologically :

Different Gene Lesions :

Point mutation mainly in RAS Balanced translocation mainly in hematopoietic tumors: 9;22 , 8;14 , 14;18

& rare in solid tumors :Ewing Sarcoma Gene amplification :

Neuroblastoma : N-MYC Breast carcinoma : HER2/NEU

Chromosomal deletions: More in nonhematopoietic & solid tumors e.g. Retinoblastoma 13q band14 also several in colorectal CA Chromosomes loss or gain : ( Aneuploidy) Result : Change in structure or quantity of

gene product

Gene Amplification :

CARCINOGENIC AGENTS

Direct Carcinogens - Directly produce damage without

prior metabolic conversion Indirect Carcinogens- (Procarcinogen) Metabolic conversion in liver by cytochrome P-450 dependent mono- oxygenases ultimate carcinogen

- CHEMICAL CARCINOGENS :

Action of chemical carcinogens :

Initiator - Chemical inducing irreversible DNA damage

Promoter -Augment effect of initiator by promoting cell growth e.g. phorbol ester (PTA) activate signal transduction or GF secretion , hormones, saccharine …..etc

No tumor develops unless the promoter is applied AFTER the initiator.

Classes of Chemical Carcinogens :

1- Alkylating Agents : Direct, used in chemotherapy of cancer may induce Leukemia

2- Polycyclic Hydrocarbons : Indirect & very strong e.g.cigarette smoke CA Lung

3- Aromatic Amines & Azo dyes : Rubber & Food Industry e.g.

naphthylamine Bladder CA

Chemical carcinogens ( Continued)

4- Nitrosamines : Endogenous or food preservatives e.g.Gastric & Colon CA…etc.

5- Aflatoxin B1 : Naturally occurring carcinogen present in fungus.

Aspergillus flavus Hepatocellular CA

Mode of action in chemical Carcinogens

Chemical carcinogens contain highly reactive electrophil groups that combine to DNA, RNA, or proteins producing mutations

Genes commonly affected are RAS & P53 May be very specific‘ Signature

Mutation’ Some strong chemicals act as Initiator &

Promoter e.g. polycyclic hydrocarbon

U-V light : - Effect depends on intensity of exposure & quantity of melanin - Production of pyrimidine dimers in DNA MUTATION in RAS , P 53 - Failed repair Skin CA - Skin cancer includes :

Squamous Cell CA Basal Cell CA Melanoma

2- PHYSICAL CARCINOGENS :

Ionizing Radiation: - Explosions Leukemia after 7 yrs.

Latent period Breast,colon, thyroid, lung CA

- Therapeutic exposure Thyroid CA, Leukemia

- Mechanism:Free radical injury Mutations in RAS, RB. P53 Asbestos fiber inhalation : Mesothelioma & Lung CA

A - DNA Viruses :

Benign squamous papilloma (wart) groups 1,2,4 & 7 * Low risk groups (6, 11) Genital Squamous Cell Papilloma * High risk group ( 16, 18 ) Squamous Cell CA in cervix, vulva, perianal & oropharyngeal regions

3- VIRAL CARCINOGENESIS :

1- HPV-Human Papilloma Virus

Mode of Action :

HPV have transforming early genes (E6,E7) inactivate suppressor genes

E6 acts on p53no apoptosis E7 binds to E2F blocks Rb action

& activates cyclins, & inhibit CDKI High risk groups have a stronger

affinity of early genes to E2F Result Cell proliferation

BURKITT’S LYMPHOMA ** B CELL LYMPHOMA HODGKIN’S LYMPHOMA subset NASOPHARYNGEAL CA

----------------------------------------- Post transplant lymphoma CNS Lymphoma in AIDS patients

2- EBV : Ebstein Barr Virus

Mode of action in Burkitt’s Lymphoma :

EBV has LMP1 gene- receptor for B lymphocytes

Induce B cell proliferation Prevents apoptosis by activating BCL2

Controlled POLYCLONAL B proliferation Infectious Mononucleosis

Dysregulation of c- myc by translocation : BURKITT’S Lymphoma (t 8:14) Malaria & Malnutrition may play a role in

immunity ( Lost T cell control ). In endemic cases EBV is identified in tumor cells

In Nasopharyngeal Carcinoma :

LMP 1 is expressed on epithelial cells activating cell proliferation

========================

LMP 1 also activates pro- angiogenic factors

Both in Burkitt Lymphoma & Nasopharyngeal Carcinoma other

environmental factors play a role

Multifactorial oncogenic effect but mainly

Immunologically mediated chronic liver disease Cirrhosis Hepatocellular CA

in 70 -85% Action :* Cell proliferation

mutation * HBV encodes Hbxprot.

growth promoting genes *Hbx binds to p 53 Inactivates suppressor function

(HCV is similar but HCV core Protein)

3-HBV ( Hepatitis B Virus )

B- Oncogenic RNA Viruses :

HTLV-1 induces Leukemia /Lymphoma

Transmitted sexually,blood or milk Mode of action : Virus TAX gene attaches to T cells: Produce cytokines +receptor

autocrine stimulation proliferation Suppresses action of TP53 &CDKI POLYCLONAL MONOCLONAL LEUKEMIA

First described as a cause for peptic ulcer Multifactorial etiology in gastric CA &

gastric lymphoma ( MALT lymphoma ) Immune mediated gastric damage with FR Occurs in only 3% after a long latent

period H.pylori contains (Cag A)genes GF Cell proliferation

Helicobacter pylori in carcinogenesis

Mode of action :

LYMPHOMA : Chronic gastritis mucosal lymphoid

follicles reactive polyclonal B cells monoclonal B cells Malt lymphoma

CARCINOMA : Chronic gastritis atrophy

intestinal metaplasia dysplasia Gastric Carcinoma

CANCERS --ASSOCIATED CARCINOGEN

CA LUNG Smoking CA CERVIX Sexual transmission of HPV CA BLADDER Rubber Industry CA LIVER Aflatoxin & HBV infection CA THYROID Radiation ANGIOSARCOMA of Liver Plastic(PVC) MESOTHELIOMA Asbestos

TUMOR IMMUNOLOGY

What is Immune Surveillance ?

Normal immunity present to protect against development of tumors

Evidence ? When there is no immunity → More

Cancers Patients with congenital immune

deficiency have 200 times risk of cancer & immunosuppressed patients have increased rates of cancers (Lymphoma)

Explanation of failed survailance

This may be lost during tumor progression

There may be acquired immunosuppression produced by oncogenic agents

Anti tumor Host Mechanisms :

1- Sensitized Cytotoxic T lymphocytes 2- Natural Killer cells may kill tumor cells without previous sensitization. 3- Macrophages activated by IFN- may destroy tumor cells

4- Humoral AB mechanisms

Tumor Antigens :

Tumors share MHC with normal cells

Tumor specific & Tumor Associated AGs may be helpful in diagnosis & follow

up of some tumors Therefore, they may act as tumor

markers

Specific & Associated Tumor AG:

1- Products of mutant oncogenes & tumor suppressor genes e.g. RAS protein

2- Mutant proteins induced by chemical and radiation induced tumors

3- Overexpressed normal cellular proteins or aberrantly expressed e.g. :

Tyrosinase in melanoma Cancer Testes Genes : MAGE-1(melanoma..) HER-2 in CA breast

4- Tumor AG produced by oncogenic viruses in HPV & EBV infection

5- Oncofetal AG: Carcinoembryonic AG (CEA) in colon and fetoprotein in liver CA 6- Several mucins: MUC-1 in breast CA and CA-125, CA-19-9 in ovarian CA 7- Cell Type- specific differentiation AG in B lymphomas (CD10&CD20)

Clinical Aspects of Neoplasia

Effects of tumors on body:

Location of tumor is of importance 1- Mass effect by pressing on vital areas e.g.airway, intestine , BV, brain,nerve obstruction, infarction , paralysis…etc 2- Local destruction of epithelial surface or BV ulceration , bleeding , infection

3- Hormonal activity

4 - Cancer Cachexia :

Wasting syndrome characterized by anorexia , loss of body fat & weight,with

marked weakness,anemia & fever.

Reduced food intake but high metabolic rate

Possibly due to release of cytokines by tumor cells & macrophages

5 - Paraneoplastic Syndrome :

Systemic symptoms that can’t be explained by effects of local or distant spread of tumor or hormones appropriate to tumor tissue.

Due to ectopic production of hormones or other factors They may precede the tumor or mimic metastases They occur in about 10%-15% of malignant tumors.

Types of Paraneoplastic Syndromes :

Endocrinopathies e.g hyperglycemia,

hypoglycemia, Cushing’s S…..etc Nerve & Muscle Syndromes e.g

myasthenia gravis Dermatologic disorders Osseous & Articular changes Vascular & hematological changes Nephrotic syndrome

Well Known Examples of Paraneoplastic Syndromes

Small Cell CA lung ACTH , ADH, Bone changes,nervous system disorders

Squamous Cell CA lung & Breast CA Parathormone related &othersHypercalcemia

Pancreatic & lung CA clotting factors Deep vein thrombosis N.B. Hypercalcemia is commonly produced by

lytic bone metastases

examples (continued)

Hepatic & Renal CA Polycythemia Pancreatic, Gastric CA Carcinoid S. Advanced Cancers Nonbacterial thrombotic

endocarditis. Colonic Adenocarcinoma Acanthosis nigricans

Grading & Staging of Tumors :

Must be documented for all malignant tumours : To quantify the aggressiveness of

tumor To outline mode of therapy To compare different modes of

therapy To give an approximate prognosis

Prognosis :

This indicates the final outcome of the disease in terms of 5year or 10 year survival.

This is influenced by : Tumor Type e.g. Lung CA versus

Lip CA Tumor Grade & Stage Host reactions

Grade of tumor: Based on level of differention :

This indicates the degree of resemblance of tumor cells to cell of origin and is always based on microscopic criteria.

Grade I : Well differentiated tumor Grade II :Moderately differentiated

tumor Grade III : Poorly differentiated tumor Grade IV : Anaplastic tumor

STAGE of Tumor :

This indicates the extent of spread of the tumor.

Clinical ,investigative procedures and pathological appearance of tumor have to be used to assess it.

It depends on : * Size of tumor * Regional lymph node involvement * Metastases to distant organs

TNM Staging System :

T : Size and extent of primary tumor(1-4)

N : Presence and extent of lymph node

involvement ( 0-3) M : Presence or absence of distant metastasis ( X0-1) e.g.T1,N1, M0-----------------------------------

Others : American Joint Committee staging system ( AJC) Stage 0-IV

- Duke’s staging for colonic CA - Lymphoma Staging system And many more…….etc Staging is more important than

grading because it affects treatment

CANCER DIAGNOSIS

General Outline :

History & clinical examination Radiographic techniques

i- X rayii- CT scaniii- MRIiv- Ultrasound

Laboratory tests : general & specialized

1- Cytological methods : Study of cells : - Smear - FNA, Brush, Fluid tapping…etc Papanicolaou stain (PAP) often

used. False(+), False (-) - A negative report does not exclude malignancy, repeat - Advise biopsy, even if (+ )

1-Morphological Methods :

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Normal PAP smear of Cervix

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Dysplastic Epithelial Cells (PAP smear)

2- Histological methods :

Biopsy of tissue: Needle & core biopsy , Endoscopic

Biopsy, or open surgical biopsy Frozen Section (Rapid technique) Paraffin Section ( 36-48 hrs. or longer ) H&E, Special histochemical stains e.g. ( PAS, CONGO RED, PERL’s stains) or by IMMUNOHISTOCHEMICAL Methods

3- Immunocytochemistry

Staining by use of monoclonal AB directed against various components in cell may help in diagnosis of undifferentiated cancers or help in identifying source of a metastatic tumor. e.g.

Cytokeratin Carcinoma Common leukocyte antigenLymphoma S 100 Neural tissue, melanocytic lesions Desmin, Vimentin Sarcoma

Undifferentiated Tumor

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Cytokeratin for epithelial cells indicating Carcinoma

Undifferentiated Malignant tumor

Desmin Positive for connective tissue indicating Sarcoma

4-Electron microscopy :

For recognition of desmosomes , or neurosecretory granules….etc. 5- Flow Cytometry : For measuring DNA content , detecting diploid versus aneuploid tumors….etc. Correlates with rate of growth & prognosis Useful in the diagnosis & classification of

Lymphoma & Leukemia

Used to identify tumor associated enzymes, hormones , antigens … etc

These are useful as markers for diagnosis of a tumor OR for assessing the progress of a known tumor

2- Biochemical Assays :

Tumor markers represent biochemical indicators of the presence of a tumor.

Their uses are to : I - Confirm diagnosis. II -Determine the response to treatment . III - Detect early relapse. Present in serum or urine. Many are present in normal & tumor tissue, so they

are not very specific but their level is important.

Types of Tumor Markers

1- Hormones : Human Chorionic Gonadotrophic Hormone ( HCG)

Elevated levels are seen in Pregnancy & Gestational Trophoblastic Disease

Calcitonin useful in diagnosis of some thyroid carcinomas Ectopic hormones in paraneoplastic S.not used

2- Oncofetal Antigens : Carcinoembryonic Antigen ( CEA ) : in fetal tissue & some malignancies – Colorectal CA & Pancreatic CA

Alpha Fetoprotein (AFP) :

Cirrhosis : Elevated Hepatocellular carcinoma : Extremely

high

3- Isoenzymes :

Prostatic Acid Phosphatase ( PAP ) levels seen in Metastatic prostatic CA Useful in : * Staging prostatic CA * Assessment of prognosis * Response to therapy.

4- Specific Proteins : Immunoglobulins secreted in Multiple Myeloma Prostate -specific antigen ( PSA ) : Present in epithelium of prostatic

ducts. * Prostatic hyperplasia &

* in Prostatic CA * Level correlates with Stage of CA

5- Several mucins

MUC-1 in breast CA CA-125 in ovarian CA CA-19-9 in pancreatic & hepatobiliary

CA

Methods used include : PCR (Polymerase Chain Reaction) FISH (Fluorescent In Situ Hybridization)

Used to detect gene rearrangement, translocations, amplifications…etc

BCR-ABL Chronic Myeloid Leukemia Monoclonal proliferation of B or T cells 13q 14 deletion in Retinoblastoma….

3- Molecular Diagnosis :

For prognosis : gene amplification HER- 2 NEU in breast carcinoma N-MYC in neuroblastoma

Detection of residual disease in chronic myeloid leukemia (BCR-ABL) Detection of genes of hereditary cancer e.g BRCA-1 in breast cancer

BE AWARE OF CANCER !!!

EARLY DIAGNOSIS of CANCER :

This is very important as many cancers are curable if they are diagnosed early. Specific symptoms should be followed up e.g. Abnormal bleeding Change of voice Change in a nevus Abnormal lump in breast An ulcer that does not heal……etc.

Specific procedures : - Self examination of the breast - Mammography - Serial PAP smears for the cervix - Serial sputum cytology in smokers - Serial urine cytology in some cases, e.g. bilharziasis, workers in rubber Screening for genetic mutations in

familial cancers.