Genetics Lecture 8 - Cancer Genetics

Question 1

By what inheritance mode are cancer predispositions inherited?

Answer 1

Autosomal Dominant with incomplete penetrance and variable expressivity.

Question 2

What is Knudson’s 2-Hit Hypothesis?

Answer 2

Two mutations are needed for tumorigenesis.

Question 3

What is more commonly inherited: a loss of function or a gain of function gene?

Answer 3

Loss of function.

Question 4

Name two classes of genes that are involved in loss of function genes that confer cancer predisposition.

Answer 4

Tumor suppressor genes (Rb, NF1, p53, APC), mismatch repair genes (MLH1, MSH2, MSH6)

Question 5

Does the 2-Hit hypothesis apply to gain of function cancer genes?

Answer 5

No, only one mutation is needed in this case.

Question 6

What are six red flags for hereditary cancer?

Answer 6

1. Early onset (before 50 years of age)
2. Multiple or bilateral tumors
3. Rare or unusual tumors
4. Combinations of certain cancers
5. Autosomal dominant pattern of inheritance
6. Lack of known contributing factors

Question 7

What is the increased risk for those who have BRCA mutations?

Answer 7

44 to 87%

Question 8

What cancers are associated with BRCA mutations?

Answer 8

Breast (early onset), ovarian, prostate, pancreatic, male breast

Question 9

What cancers are associated with Lynch syndrome?

Answer 9

Colorectal, uterine, ovarian, GI cancers.