This study examined the impact of HER2-low expression on survival outcomes in triple-negative breast cancer (TNBC) of high-grade special histological type (ST) and no special type (NST) and investigated the prognostic significance of TNBC subtype (high-grade ST vs. NST) within HER2 0 and HER2-low expression subgroups. The gene discussed is ERBB2; the disease is triple-negative breast carcinoma.