Pharmacogenomics>Targeted Therapy Selection Practice Test

Ms. R is a 58-year-old woman with newly diagnosed stage II invasive ductal carcinoma of the breast. Pathology shows ER-positive, PR-positive disease. HER2 testing by immunohistochemistry is 3+, and fluorescence in situ hybridization confirms HER2 gene amplification. Baseline echocardiogram reveals a left ventricular ejection fraction of 62%. She has well-controlled hypertension, no history of heart failure, and normal renal and hepatic function. The oncologist plans adjuvant systemic therapy following lumpectomy and sentinel node biopsy. She asks the pharmacist which targeted therapy should be added to her chemotherapy backbone given the tumor profile. Which of the following therapies is most appropriate based on this biomarker result?

A 52-year-old woman is diagnosed with stage II invasive ductal carcinoma of the left breast. Tumor biomarkers show ER 0%, PR 0%, and HER2 overexpression with IHC 3+ confirmed by FISH amplification (HER2/CEP17 ratio 2.6). She has no history of cardiovascular disease; baseline echocardiogram shows LVEF 62%. CBC and chemistry panel are within normal limits. She underwent lumpectomy with positive sentinel nodes (2 of 3) and is scheduled to begin adjuvant systemic therapy. The oncology team plans anthracycline- and taxane-based chemotherapy, followed by targeted therapy guided by biomarkers. She asks which drug specifically targets the abnormal receptor identified on her tumor. Current medications include lisinopril and vitamin D. She is premenopausal and uses barrier contraception.