Molecular biology of cancer

Question 1

Hallmarks of cancer

Answer 1

Growth signal autonomy
Evasion of growth inhibitory signals
Avoiding immune destruction
unlimited replicative potential
Tumor-promoting inflammation
Invasion and metastasis
Angiogenesis
Genome instability and mutation
Evasion of death
Reprogramming energy metabolism

Question 2

Hallmarks of cancer- Growth signal autonomy

Answer 2

Normal cells need external signals from growth factors to divide. Cancer cells are not dependent on normal growth factor signaling.

Question 3

Hallmarks of cancer - Evasion of growth inhibitory signals

Answer 3

Normal cells respond to inhibitory signals. Cancer cells do not respond to signals. Acquired mutations or gene silencing interfere with the inhibitory pathways.

Question 4

Hallmarks of cancer - Avoiding immune destruction

Answer 4

Successful cancer cells may be those that do not stimulate an immune response

Question 5

Hallmarks of cancer - Unlimited replicative potential

Answer 5

Normal cells have an autonomous counting device to define a finite number of cell doublings, after which they become senescent. This cellular counting device is the shortening
of chromosomal ends, telomeres, that occurs during every round of DNA replication. Altered regulation of telomere maintenance results in unlimited replicative potential.

Question 6

Hallmarks of cancer - Tumor-promoting inflammation

Answer 6

all tumors contain inflammatory immune cells, which can provide growth factors and enzymes that promote angiogenesis and invasion.

Question 7

Hallmarks of cancer - Invasion and Metastasis

Answer 7

The movement of cancer cells to other parts of the body

Question 8

Hallmarks of cancer - Angiogenesis

Answer 8

vascular architecture is rather constant in adult, cancer cells induce angiogenesis, the growth of new blood vessels, needed for tumor survival and expansion

Question 9

Hallmarks of cancer - Genome instability and mutation

Answer 9

Acquiring the core hallmarks of cancer usually depends on genomic alterations, including mutations, epigenetic reprogramming, and physical changes to chromosomes

Question 10

Hallmarks of cancer - evasion of cell death

Answer 10

Normal cells are removed by apoptosis, cancer evades apoptotic signals

Question 11

Hallmarks of cancer - Reprogramming ener metabolism

Answer 11

cancer cells carry out glycolysis, even in the
absence of oxygen. Glycolysis intermediates can be used in biosynthetic pathways.

Question 12

Cancer at genome level

Answer 12

DNA of tumor cells contains many alterations, ranging from subtle point mutations (changes in a single base pair) to large chromosomal aberrations, such as deletions and chromosomal translocations.
The accumulation of mutations in cells over time represents a multi-step process that underlies carcinogenesis.

Question 13

Longer life expectancy as risk for cancer

Answer 13

The longer we live, the more time there is for our DNA to accumulate mutations which may lead to cancer.