Robert Farley University of Rhode Island Department of Biomedical Engineering.

Robert FarleyUniversity of Rhode Island

Department of Biomedical Engineering

Stem cells have unique features Un-specialized Ability to form any cell Can divide themselves for long periods of time Self-renewal (at cell division, one or both

daughter cells retain the same biological properties as the parent cell) self-renewal is especially notable, because its

constant changing is highly relevant to malignancy

Mutation of normal cells “Normal” cells will group together to form

different types of tissue Like normal cells, cancer cells will also

group together forming tumors Tumors can either be malignant or

benign Malignant – cancerous

Studies have shown that the characteristics of stem-cell systems and/or the specific stem-cell properties are relevant to some forms of human cancer

These properties of “tumor-initiating” cells have similar properties to stem cells

Cancerous cells with these functional properties have been termed "cancer stem cells“

Just as some forms of cancer cells mutate from certain cells it is possible that cancer stem cells arise by mutation from normal stem cells

Cancer stem cells can be the source of all the malignant cells in a primary tumor

They can be the drug-resistant cells that are responsible for relapse after a chemotherapy-induced remission

They can give rise to distant metastases Because stem cells have the characteristic

to form any type of cell, cancer stem cells have the ability to perform any of the actions mentioned above

Hematopoietic System contains organs and tissue with the main focus being the lymph nodes, spleen and bone marrow

One of the most prevalent types of cancer involved in this system is Leukemia

Cancer stem cells are evident in chronic myelogenous leukemia (CML) and acute myelogenous leukemia (AML)

Due to the cancer stem cells, regular treatment of these types of cancer are usually ineffective

AML cancer stem cells have surface markers, such as the interleukin-3–receptor

This specific receptor is not found on the normal stem cell

This marker is useful for antibody based therapeutic treatment

Scientists hope that by using this receptor to target the cancer stem cells, treatment for AML will be more effective

There has been research on drugs that specifically control leukemia-cell growth

Certain inhibitors have been used to stop the growth of the CML cells ABL kinase inhibitor imatinib mesylate

However, drugs do not kill the CML cells therefore allowing the cancer to relapse after therapy is finished

The cancer stem cells are responsible for the replapse

By targeting the cancer stem cells involved with CML treatment should become more effective

Studies have shown that patients with advanced stages of metastatic breast cancer demonstrated that cells with a specific cell-surface antigen could successfully establish themselves as tumor xenografts

Experiment done with immunodeficient mice where human breast cancer cells were implanted into the mammary fat pad of the mouse

Experiment showed that only the cancer stem cells could successfully grow the tumor inside the mouse whereas the majority of the malignant cells failed to form any type of tumor

By showing that the cancer stem cells can act as xenografts, it gives scientists another way to differentiate between normal stem cells and cancer stem cells

By categorizing these stem cells due to the properties they possess it is easier to explain how cancer stem cells work

Like cancer stem cells in leukemia, much work is to be done with breast cancer as well

Determining how relevant stem cells are in the treatment of all cancers

How do different chemotherapy agents affect the evolution of cancer stem cells during conventional treatment?

Do different cancer stem cells have different weak points? determining whether the same tumor-specific

mechanisms of growth and survival are active across multiple cancer types

Will the current forms of treatment provide a competitive advantage for cancer stem cells?

Will targeting self renewal cells kill them or just suppress them during treatment?

However, doctors and scientists feel strongly that the eradication of cancer stem cells will be necessary to improve the outcome of treatment for at least

some cancers

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