breast genetics

Question 1

Breast cancer causation

Answer 1

100% is genetic, cancer is a genetic disease
5-10% of breast cancers are hereditary
15-20% are familial
70-80% are sporadic

Sporadic- usually diagnosed after menopause, low incidence of cancer in the family, environmental factors, agem hormome, lifestype

Question 2

Hereditary breast cancer

Answer 2

main cause is a single germline gene mutation in the family, multiple generations often affected, typically young age of breast cancer onset
Clustering of related types of cancer
hereditary breast and ovarian cancer (HBOC)- ashkenazi jew, triple negative tumors, cowden syndrome(PTEN), Li fraumeni (TP53)

Question 3

cancer progression

Answer 3

First mutation present in gene at conception and in germline

Oncogenes- accelerate cell division, cancer arises when stuck in on mode

Tumor suppressor genes- DNA damage response, cells (brakes) for tumor growth, cancer arises when both brakes fail

Question 4

Sporadic 2 hit hypothesis

Answer 4

nothing to do with inheritance

Question 5

Red flags for hereditary cancer

Answer 5

EMR
E- early age at diagnosis, <45 years of age regardless of family history, or 2 fam members and one is under 50

M- multiple in the family, 3 or more

Rare- a family member with ovarian, pancreatic, met or male breast cancer