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What is BRCA 1 responsible which histological type breast cancer? and explain in detail?
ANSWER: (D) Medullary carcinomaREF: Robbins 8th edn Page 1088,1089, Sabiston 17th edp. 891, CSDT 11thed p- 335, Schwartz 9th ed chapter 17BRCAl-associated breast cancers are commonly poorly differentiated, have "medullary features" (a syncytial growth pattern with pushing margins and a lymphocytic response), and do not express hormone receptors or overexpress HER2/neu (the so-called "triple negative" phenotype). Their gene profiling signature is very similar to basal-like breast cancers, a distinct molecular subtype that is discussed later. BRCA1 cancers are also frequently associated with loss of the inactive X chromosome and reduplication of the active X, resulting in the absence of the Barr body. BRCA2-associated breast carcinomas also tend to be relatively poorly differentiated, but are more often ER positive than BRCA1 cancers.