Molecular profiling of an invasive ductal carcinoma from a 46-year-old woman reveals amplification of a gene located at chromosome 17q12. The encoded protein is a growth factor receptor whose overexpression correlates with poor prognosis and predicts response to a monoclonal antibody against it. Which gene was amplified?

• A ERBB2 (HER2) ✓
• B ERBB1 (EGFR)
• C MYC
• D BRCA1

Explanation

ERBB2 (HER2/neu) lies at 17q12 and encodes a receptor tyrosine kinase of the epidermal growth factor receptor family without a known ligand; it signals by heterodimerizing with other ERBB receptors. Gene amplification occurs in 15 to 20% of breast cancers, defines an aggressive subtype, and guides trastuzumab therapy. The best distractor is EGFR, which is also a receptor tyrosine kinase amplified in some carcinomas, but its locus is 7p11, not 17q12.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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