Increased susceptibility to breast cancer is likely to be associated with a mutation in the following gene: (AIPG 2011)
Breast cancer can be either familial (associated with germline mutation) or sporadic (associated with somatic mutation).
The familial breast cancet is caused due to mutation in the following 4 genes:
• P53 tumor suppressor gene (called Li Fraumeni syndrome having multiple malignancies like breast cancer, osteogenic sarcoma etc.)
• PTEN gene: Gene on chromosome 10q associated with epithelial cancers of breast, endometrium and thyroid.
• BRCA1 gene: Located on 17q females having mutant gene have increased incidence of breast and ovarian cancer
whereas males having mutant gene have high incidence of breast and prostate cancer.
• BRCA2 gene: Located on chromosome 13q is associated with increased incidence of breast cancer in men and women.
Sporadic breast cancer is associated with mutation in p53 gene (p53 defect is present in 40% of human breast cancer as an acquired defect) and PTEN gene.
Since, incidence of sporadic cancer is much more than familial cancer, so the most important gene mutation increasing susceptibility to breast cancer should be answered as p53.