Question

1. Name the ten hallmarks of cancer. Briefly (1-2 sentences) describe how each hallmark contributes to making a cell cancerous.

Answer 1

Hallmarks of Cancer:

1. Self-sufficiency in growth signals

Cancer cells do not need growth factor-stimulated signals to multiply while normal body cells require hormones and other molecules that act as signals for them to grow and divide.

2. Insensitivity to anti-growth signals

The cell division is a tightly controlled process controlled by tumour suppressor genes which prevent cell growth and division. Cancer cells are generally resistant to these growth-preventing signals.

3. Evading programmed cell death

Apoptosis is a form of programmed cell death (cell suicide), the mechanism by which cells are programmed to die in the event they become damaged. Cancer cells are characteristically able to bypass this mechanism.

4. Limitless replicative potential

Normal body cells don't have the ability to divide indefinitely. They have a limited number of divisions before the cells become unable to divide (senescence) or die (crisis). Cancer cells are apparently capable of indefinite growth and division (immortality). But those immortal cells have damaged chromosomes, which can become cancerous.

5. Sustained angiogenesis

Angiogenesis is the process by which new blood vessels are formed. Cancer cells have the ability to start angiogenesis, ensuring that such cells receive a continual supply of oxygen and other nutrients.

6. Tissue invasion and metastasis

Cancer cells can break away from their site or organ of origin to invade surrounding tissue and spread (metastasize) to distant body parts.

7. Deregulated metabolism

Most cancer cells use abnormal metabolic pathways to generate energy.

8. Evading the immune system

Cancer cells are able to avoid interaction with the body via a loss of the interleukin-33 immune system.

9. Genome instability

Cancer cells generally have severe chromosomal abnormalities which worsen as the disease progresses.  Small genetic mutations are most likely what begin tumorigenesis, but once cells begin the breakage-fusion-bridge (BFB) cycle, they are able to mutate at much faster rates.

10. Inflammation

Inflammation leads to angiogenesis. The degradation of the extracellular matrix necessary to form new blood vessels increases the odds of metastasis.

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