Genetic Predisposition to Cancer

Question 1

What percentage of breast cancer is sporadic?

Answer 1

70-80%

Question 2

What percentage of breast cancer occurs in family clusters?

Answer 2

15-20%

Question 3

What percentage of breast cancer is hereditary?

Answer 3

5-10%

Question 4

What percentage of ovarian cancer is sporadic?

Answer 4

90-95%

Question 5

What percentage of ovarian cancer is hereditary?

Answer 5

5-10%

Question 6

What percentage of colorectal cancer is due to Lynch Syndrome?

Answer 6

5%

Question 7

What percentage of colorectal cancer is due to FAP?

Answer 7

1%

Question 8

What are germline mutations?

Answer 8

Mutation present in egg or sperm and are heritable. Cause of cancer family syndromes

Question 9

What are somatic mutations?

Answer 9

Occur in non-germline tissues and are noninheritable

Question 10

What are oncogenes?

Answer 10

Normal genes which regulate cell growth

Question 11

What occurs in the first mutation to an oncogene?

Answer 11

Leads to accelerated cell division

Question 12

What is Lynch Syndrome?

Answer 12

Mutation in mismatch repair genes

Leads to an excess of colorectal, endometrial and urinary tract, ovarian and gastric cancer

Question 13

What are the risks of having the BRCA1 and BRCA2 gene?

Answer 13

Breast Cancer 60-80%
Second primary breast cancer 40-60%
Ovarian Cancer 20-50%

Males have an increased risk of prostate and breast cancer (especially BRCA2)

Question 14

What is Autosomal Dominant Inheritance?

Answer 14

Each child has 50% chance of inheriting the mutation, no skipped generations and equally transmitted by men and women