Molecular Biology of Cancer

Question 1

6 Hallmarks of Cancer

Answer 1

1. Sustaining proliferative 2. Evading growth suppressors 3. Activating invasion and metastasis 4. Enabling replicative immortality 5. Inducing angiogenesis 6. Resisting cell death

Question 2

Newer Hallmarks

Answer 2

• Avoiding immune destruction - Deregulation of cellular genetics - Genome instability and mutation - Tumor-promoting inflammation

Question 3

Self- sufficiency mechanisms:

Answer 3

• hyperactivity of Ras protein - increase in GF receptors - mutation in any intracellular signalling pathway leading to growth.

Question 4

Evading growth suppressors

Answer 4

p53 mutation allows the cell to evade apoptosis and also allows it to remain in the cell cycle.

Question 5

p53 function

Answer 5

checks if the copy of DNA is faulty and if it is it arrests the cell cycle

Question 6

Resisting cell death

Answer 6

there are many ways a cancer can evade apoptosis

Question 7

How is replication monitored in cells?

Answer 7

Telomeres - the end problem in replication with DNA polymerases causes a shortening in telomeres after every division.

• when it runs out of telomere then it is signalled for apoptosis.

Question 8

how do cancers maintain immortality

Answer 8

cancers can induce telomerase which extends the telomeres.

Question 9

Angiogenesis explain

Answer 9

Tumour secretes VEGF which increases blood vessels expression and movement to tumour, this growth allows blood supply for the tumour

Question 10

Invasion and Metastasis

Answer 10

cells on the primary periphery of the primary tumour can invade surrounding tissues and then end up in the blood stream and travel to another part of the body.

Question 11

Multi-Hit hypothesis

Answer 11

It takes most of the 6 hallmarks for cancer to develop (some exceptions e.g. leukaemias do not need angiogenesis). It can acquire the hallmarks in different orders and cancers can be polyclonal.