Genetics of Cancer

Question 1

Which of hte following supports the hypthesis that a given tumor is due to the conversion of a proto-oncogene?

Answer 1

Tumor DNA converts normal cells into cells with a malignant phenotype

The primary function of proto-oncogenes is to promote cell growth. Under normal circumstances, the action of protooncogenes are tightly regulated to coincide with the overall developmental and maintenance program of the body, and are held in check by a different set of genes that suppress cell growth, called tumor suppressor genes.

Question 2

The retinoblastoma gene (Rb) is considered a recessive gene because…

Answer 2

both copies of the gene have to be mutated for the tumor phenotype to be manifested

Inheritance is AD b/c only one copy of the mutated gene is inherited, but the second hit results in retinoblastoma which is they the tumor phenotype is recessive

Question 3

Oncogene activation is NEVER what?

Answer 3

deletion

Question 4

Oncogenic retroviruses differ from non-oncogenic retroviruses in that they contain
A. a DNA genome instead of an RNA genome
B. an additional gene which promotes uncontrolled cell growth
C. an increased amount of reverse transcriptase
D. an increased number of long terminal repeats (LTR)
E. an increased number of retrotransposons

Answer 4

B. an additional gene which promotes uncontrolled cell growth

Question 5

Activation, amplification, or over-expression of members of this family are often associated with malignancy.
A. FGF receptor genes
B. HOX genes
C. MYC genes
D. PAX genes
E. SHH signaling pathway genes

Answer 5

C. MYC genes

Question 6

Oncogenic mutations in RAS and MyC are ‘cooperative’ in that they lead to a higher incidence of tumors in mice compared to mutations in eitehr gene alone. Which of the following best explains the phenomenon?
A. Oncogenic mutations in RAS and MyC increase the sensitivity of cells to apoptosis.
B. Oncogenic mutations in RAS and MYC result in synergistic increase in MYC gene expression
C. Oncogenic mutations in RAS increase proliferation while mutations in MYC promtote multi-drug resistance.

Answer 6

B. Oncogenic mutations in RAS and MYC result in synergistic increase in MYC gene expression

high MYC = cancer