A more profound challenge stems from the high degree of molecular heterogeneity in breast cancer—categorized into subtypes such as Luminal A, Luminal B, human epidermal growth factor receptor 2 (HER2)-positive, and triple-negative based on distinct molecular marker profiles [6]—which renders the single therapeutic strategy approach inadequate for meeting the pressing demands of personalized medicine. The gene discussed is ERBB2; the disease is breast carcinoma.