Cancer stem cells

Question 1

What are Cancer stem cells

Answer 1

Cells within a tumor that are similar to normal stem cells

• The have the ability to self-renew
• They can give rise to differentiated tissue
• They can initiate the malignancy since these can go through EMT
• They drive tumor progression
• CSC cause and propagate the disease in almost all cases

Question 2

The two theories about CSC origin

Answer 2

• Normal stem cell have lost its regulation to proliferate (SC –> CSC), these start to differentiate and form bulk of cancer
• More differentiated progenitor cancer cells have acquired abilities to self-renew, these normal cell have gone back to CSC like cells.

Question 3

What does CSC contribute to

Answer 3

CSC contribute to

• clonality of tumors
• heterogeneity
• initiation and development of tumors
• clinical challenges

Question 4

CSCs are important from a clinical aspect since these are often resistant to therapy, why ?

Answer 4

CSC compared to other cancer cells:

• Slow in growth, current therapies target fast growing cells
• High level of anti-apoptotic molecules
• Resistance to DNA or oxidative damage
• Protected by stromal cells
• Clonal selection of tumors that are resistant to treatment, causing relapse of tumors “survival of the fittest”
• Treatment may cause mutations, giving resistance to tumors

Question 5

What is Chemotherapy and Radiotherapy

Answer 5

Chemotherapy = Cell toxic medication, targets dividing cells . You kill the cancer bulk but slow dividing cells as CSC remain

Radiotherapy = Laser based therapy, aim is to damage DNA and since cancer cells grow so rapidly they are unable to repair and thereby die. Also ineffective in slow growing cells such as CSC