In contrast, breast cancer in elderly patients generally has favorable biological and histological features: hormone receptor-positive and HER2/neu status-negative, lower proliferative rates, apocrine carcinoma, and mucinous carcinoma.37–40 On the other hand, elderly patients are often poor candidates for cytotoxic chemotherapy because of their susceptibility to serious side effects.41,42 Therefore, we observed that 10-year RS was better in elderly patients than in the other age groups, but improved only a slight 1.0% over time (87.6% vs 88.6%). The gene discussed is ERBB2; the disease is mucinous adenocarcinoma.