Breast cancer is the second most frequent cancer worldwide, andthus, timely screening of breast cancer is crucial in healthcare andtreatment.1,2 Human epidermal growth factor receptor 2(HER2) is a reliable, predictive, and prognostic biomarker for breastcancer due to the aberrant amplification of the HER2 driver gene,resulting in the overexpression of the HER2 protein and the formationof HER2-positive breast cancer. The gene discussed is ERBB2; the disease is breast cancer.