Cancer-Breast, Lynch Syndrome

Question 1

Breast cancer-BRCA1 and BRCA2

Answer 1

• dominant genes
• normally they are tumor suppressor genes highly expressed in breast tissue (help repair damaged DNA, with important role in dsbreak repair)

Question 2

Lynch syndrome-HNPCC

Answer 2

• increases risks for many types of cancer because it is a mutation in a mismatch repair system gene (MLH1, MSH2, MSH6, PMS2)
• autosomal dominant
• colon, rectum, stomach, small intestine, liver, brain, skin, ovaries, uterus

Question 3

BRCA1 and BRCA2 prevalence in Ashkenazi Jews

Answer 3

1:40 (compared 1:400-1:800 in general population)

Question 4

Lynch syndrome-prevalence

Answer 4

1:440

Question 5

Tumor suppressors vs. proto-oncogene inheritance

Answer 5

• tumor supressors: recessive, but second hit likely so act as dominant
• oncogenes: dominant