<s>[INST] context: " In women with hereditary breast - ovarian cancer, two susceptibility loci have been identified:

BRCA -1 → located on chromosome 17 and
BRCA - 2  → located on chromosome 13

"About 25% of familial cancers (or around 3% of all breast cancer) can be attributed to two highly penetrant autosomal dominant genes BRCA1 and BRCA2"                                                                                
Coming to the question

This woman is suffering from familial breast carcinoma as (family history positive for ovarian cancer)
The most common gene associated with familial breast cancer is BRCA-1 (52%) followed by BRCA-2 (32% of all familial cancers).
BRAC-1 and BRAC-2 are associated with ovarian cancer, so a family history of ovarian carcinoma may be positive. 

Remember

The most common gene involved in famiilial breast cancer → BRCA-1
The most common gene involved in sporadic breast cancer → p53
Most common gene involved overall (Hereditary plus sporadic) → p53
The maximum increase in susceptibility to breast cancer is seen with → p53 mutation (>90%) whether it is sporadic or Hereditary. [/INST] question: A female patient presented with a firm mass of 2 x 2 ems in the upper outer quadrant of the breast. She gives a family history of ovarian carcinoma. The investigation that needs to be done to assess for mutation is - | options: A: p53 B: BRCA-2 C: Her 2/Neu gene D: C-myc gene | answer: B </s>