Abstract:Objective To explore the characteristics and clinical significance of molecular subtypes and immunophenotypes of breast medullary carcinoma (MC). Methods Molecular classification was performed in 29 specimens of MC and 180 middlehigh level invasive carcinomas of no specific type (NST) based on the expressions of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor-2 (HER-2) and Ki-67 with immunohistochemical method. The expressions of Ecadherin, P53, Ki-67 and CD57 in basallike subtype carcinoma of two groups and the clinicalpathological features were analyzed retrospectively. Results The basal-like subtype carcinoma accounted for 58.6% (17/29) and 12.2% (22/180) in MC and NST group respectively. There were no statistical differences in the expressions of Ecadherin, P53 and Ki-67 between the two groups of basallike subtype carcinoma (P＞0.05). The CD57 positive expression rates of the two groups were 88.2% (15/17) and 31.8% (7/22), and the difference was statistically significant (P=0.001). The lymph node metastasis rates were lower, and the distant metastasis rate was 23.5% (4/17) in MC group and 68.2% (15/22) in NST group, which showed statistical difference (P=0.01). Conclusion In breast tumor, MC is less common, and its histological grade is high, and basal-like subtype is in the majority. This subtype in MC shows better prognosis than other basallike subtype carcinomas and lymphocytes infiltration in the stroma may be an important factor.

Key words:Breast neoplasms,Carcinoma, medullary,Immunophenotyping,Immunohistochemistry