microRNA-10b expression and its correlation with molecular subtypes of early invasive ductal carcinoma

The present study aimed to determine whether the expression of microRNA (miR)-10b was correlated with the molecular subtypes of early invasive ductal carcinoma of the breast. In situ hybridization was used to detect the expression of miR-10b in 193 patients diagnosed with early invasive ductal carcinoma. Immunohistochemistry was performed to evaluate the expression of estrogen receptor (ER)-α, progesterone receptor (PR) and human epidermal growth factor receptor-2 (Her-2). The positive expression rate of miR-10b in patients with early invasive ductal carcinoma with ER-α (+) or PR (+) was decreased compared with ER-α (−) or PR (−) patients (P<0.05). Furthermore, the positive expression rate of miR-10b in patients with Her-2 (−) was significantly increased compared with patients that were Her-2 (+) (P=0.031). The positive expression rate of miR-10b in the luminal B subtype was significantly decreased compared with that in the luminal A, Her-2 and basal-like subtypes (P=0.037). In patients that were identified as miR-10b (+), the median disease-free survival time was significantly increased in patients that were ER-α (+)/PR (+)/Her-2 (−) compared with patients that were ER-α (−)/PR (−)/Her-2 (+) (P<0.05). In addition, the median disease-free survival time was significantly decreased in Her-2 overexpression and basal-like subtypes when compared with luminal A and B subtypes (P<0.05). The molecular subtype was an independent prognostic factor for early invasive ductal carcinoma (odds ratios for luminal B, Basal-like, and Her-2 overexpression were 2.900, 5.232 and 4.214, respectively; all P<0.05). Positive expression of miR-10b may also be a prognostic risk factor (odds ratio >1), though this was not statistically significant (P>0.05). The present findings indicated that miR-10b-positive expression was correlated with the expression of ER-α, Her-2 and the molecular subtypes of early invasive ductal carcinoma of the breast.