Lab diagnosis of neoplasia

LAB DIAGNOSIS OF NEOPLASIA

PRESENTED BY:

MADHUR KUMAR SEJWAL

VARIOUS METHODS OF DIAGNOSIS

a. Cytological and Histopathological techniques

b. Immunocytochemistry & immunohistochemistry

c. Molecular Diagnosis

d. Flow cytometry

e. Tumour markers

A) MORPHOLOGICAL METHODS

i. FNAC

ii. Exfoliative cytology

iii. Abrasive cytology

iv. Washings and lavage Techniques

I) FNAC

II) EXFOLIATIVE CYTOLOGY

Tumour cells are less cohesive, hence are shed from lining epithelium to body cavities, collected and studied.

Examples: vaginal, cervical smears

urine containing cells from GU

sputum

effusions in the body

III) ABRASIVE CYTOLOGY

Surface scraped using Ayre’s Spatula or brush.

With or without optic guidance

Examples: cervical smears (PAP smear)

bronchoscopic brushings

endoscopic brushings from lesions of GIT

IV) WASHINGS AND LAVAGE

• Normal saline is instilled into body cavity and reaspirated back, collecting shed cells

Examples: gastric lavage, peritoneal lavage, bladder lavage

Fixative used: 95% ethylalcohol or cytospray

Stains used: Papanicolaou stain or Giemsa stain

ADVANTAGES OF CYTOLOGY• Rapid

• No hospitalization

• Minimally invasive

• Rapid, accurate diagnosis in expertise hands

Disadvantage of cytology:• Small sample size and sampling errors

• Cannot comment on architecture and invasion

HISTOPATHOLOGY

Fixative used: 10% neutral Formalin

Various steps:

1. Fixation

2. Dehydration

3. Clearing

4. Impregnation

5. Staining

6. Examination of slide

FROZEN SECTION

Cryostat used

Liquid N at -190 C or liquid carbon dioxide at -90 C used to freeze IC water into ice (embedding medium)

Used for:

Rapid ‘on-table’ diagnosis

Preservation of enzymes and labile substances like lipids and glycogen

Determining nature of mass lesion

B) IHC AND ICC

USES:

1. Diagnosis of undifferentiated neoplasms.

o (+) cytokeratins & mucins carcinoma

o (+) desmin & vimentin sarcoma

o (+) CD antigen lymphoma

2. Detection of site of origin of metastatic tumours.

o Detect tissue specific or organ specific ag in a biopsy specien of the metastatic deposit e.g: PSA, CEA, thyroglobulin

3. Detection of molecules that have therapeutic or prognostic significance

o ER/PR on cells of ca.breast

4. For categorisation of lymphomas and leukemias

C) MOLECULAR TECHNIQUES

F.I.S.H

PCR

Gene chip method

• F.I.S.H

DNA probe of known complementary receptors couple with fluorescent dye and applied to nucleus. The specific sequences bind to the complementary DNA

• PCR

• GENE CHIP METHOD

They are gene scanning techniques, based on oligonucleotide arrays called DNA chips, that provide a rapid method to analyze thousands of genes simultaneously

USES

1. Diagnosis of malignancy- PCR based detection of BCR-ABL gene provides molecular diagnosis of CML.

2. Categorisation of leukemias & lymphomas- PCR based detection of TCR allows distinction between monoclonal(neoplastic) and polyclonal( rxctive) proliferations.

3. Prognosis and behaviour- FISH and PCR methods can be used to dectect amplification of oncogenes such as HER2/NEU in ca.breast – bad prognosis.

4. Detection of minimal residual disease- detection of BCR-ABL transcripts give measure of residual disease in patients treated for CML.

5. Diagnosis of hereditary predisposition-

Primary realtives are screened for germ-line mutations to allow for an opportunity for prophylactic surgery and genetic counselling e.g: BRCA1 in ca.breast.

D) FLOW CYTOMETRY

Rapidly and quantitatively measure individual cell characteristics (e.g membrane antigens, DNA content of tumour cells)

Useful in identification and classification of lymphomas and leukemias

To detect aneuploidy that carries bad prognosis.

E) TUMOUR MARKERS

Biochemical assays for tumour-associate enzymes, hormones, oncofetal antigens, proteins, mucins or molecular markers.

Indicators for the presence of tumours.

Useful in determining the effectiveness of therapy or detecting any recurrence.

Tumour markers have only a PROGNOSTIC value.

Importance:

i.Pre-op:

a)To support diagnosis

b)Help assess tumour load

ii.Post-op:

a) efficacy of treatment. Whether there is any residual disease.

REFERENCES:

Class notes

Robbins BASIC PATHOLOGY.