| Objective:To explore the relationship between molecular subtypes and clinicopathological features and prognosis of breast cancer in Chinese women.Methods:628 Chinese women with breast cancer were classified into four molecular subtypes according to their ER, PR and HER2 status which were tested by ICH or FISH technique if they were dubious. The subtypes included:basal (ER-and/or PR-,HER2-),Her2/neu(ER- and/or PR-,HER2+),Luminal A(ER+ and/or PR+,HER2-), Luminal B(ER+ and/or PR+,HER2+).The prevalence rate of each breast cancer molecular subtype was analyzed. The relationship between molecular subtypes and clinicopathologic features was determined.The DFS (disease-free survival) of each molecular subtype was analyzed.Results:The subtypes differed significantly by mean age (P<0.001). In addition, the subtypes did not differ by menopausal status (P=0.314). However, when samples were stratified into age-specific groups (≤35 years,36 to 50 years,50 to 65 years,>65 years), a significant difference was noted (P=0.001). In the≤35 year age group, the basal subtype (36.8%) was more prevalent than the luminal A (29.2%,), the luminal B (16.5%) and the Her-2/neu (17.5%) subtypes respectively (P<0.001). In contrast, in all of the other age groups, the luminal A subtype was found to be the most prevalent (P<0.001).There was significant difference in the tumor grade among the four subtypes (P=0.004). The number of patients with the gradeⅢtumor in the basal subtype and the HER2/neu subtype was significantly increased (P<0.001). There was significant difference in the tumor size among the molecular subtypes (P<0.001).When the data were stratified by tumor size as three groups (≤2 cm,2-5 cm and>5 cm), no significant difference was found among the four subtypes (P=0.644).Among the molecular subtypes, significant difference was found in both the incidence of any nodal metastases (P=0.003) and the incidence of four or more nodal metastases (P=0.024). Patients with Her-2/neu more frequently had any nodal metastases than other subtypes, and they were more likely to have involvement of four or more nodal metastases. In contrast, there were less nodal metastases in the basal subtype patients in both levels above. In the multivariate analysis, only the basal subtype was found to differ significantly from the luminal A subtype with a decreased risk of any nodal metastasies (P<0.001, OR 0.6:95% CI,0.3-0.8). Moreover, the subtype classification can also predict four or more nodal metastases. The Her-2/neu subtype patients were 2.1 (95% CI,1.5-5.9) times more likely to develop four or more nodal metastasis than the luminal A subtype patients (P<0.001). The basal subtype patients had significantly lower odds ratio (P<0.001, OR 0.7:95% CI,0.4-0.9).Among the four subtypes, there was a significant difference in AJCC tumor stage (P=0.029). The advanced stage tumors happened more in the Her-2/neu subtype than other subtypes. In the multivariate analysis,,Her-2/neu subtype patients were 1.5 (95% CI,1.2-4.1) times more likely to develop AJCC stageⅢtumors compared to the luminal A subtype(P<0.001).There was significant difference among the four subtypes in radiotherapy (P=0.047). The Her-2/neu subtype patients more frequently received radiotherapy than the other subtype patients. In addition, there was no significant difference among subtypes in operation and chemotherapy.Conclusion:In this study, we found prevalence of the molecular type of breast cancer in China was different from other country. Our study also revealed a different relationship between molecular subtypes and clinicopathologic features including tumor mean size,age in diagnosis,nodal involvement,tumor AJCC grade,tumor nuclear grade,radiotherapy,and so on.No significantly statistical difference was found by Menopausal status,surgical method,and,chemotherapy.In the multivariate analysis adjusting for confounding factors, the BC subtype was proved to be an independent predictor of nodal involvement and AJCC tumor stage.
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