The patient underwent a needle biopsy of the breast mass, which indicated the diagnosis of invasive ductal carcinoma nuclear grade 1. Results of immunohistochemistry revealed positive estrogen receptor and progesterone receptor and HER2 1+ score (HER2-negative) results; additionally, the Ki-67 index indicated that 50% of the cells were positive (a luminal B-like subtype that was HER2-negative). The gene discussed is ERBB2; the disease is invasive ductal breast carcinoma.