Compared with older patients (more than 40 years), younger women (less than 40 years) were significantly associated with more IDC (92.57%), poorly differentiated tumor (51.40%), late-stage tumor (46.59% of stage II tumor; 12.65% of stage III tumor), or more HER2 over-expression and triple-negative subtype (20.86% of HER2 over-expression subtype; 15.89% of triple-negative subtype). The gene discussed is ERBB2; the disease is neoplasm.