The functional role of IGFBP5 in breast cancer is complicated.Experimental and bioinformatics studies have shown that IGFBP5 is targeted by miR-140-5p and miR-193b, although this has not yet been proven in clinical samples.The aim of this study was to evaluate the expression of miR-140-5p and miR-193b in breast RAF/LAF Loveseat w/CUSH (2/CN) cancer and adjacent normal tissue and assess its correlation with IGFBP5 and the clinicopathological characteristics of the tumors.IGFBP5 protein expression was analyzed immunohistochemically and IGFBP5, miR-140 and miR-193b mRNA expression levels were analyzed with real-time RT-PCR.
Tumor tissue had higher miR-140-5p expression than adjacent normal tissue (p = 0.015).Samples with no immunohistochemical staining for IGFBP5 showed increased miR-140-5p expression (p = 0.009).
miR-140-5p expression was elevated in invasive ductal carcinomas (p = 0.002), whereas basal-like tumors had decreased expression of miR-140-5p compared to other tumors (p = 0.008).Lymph node-positive samples showed an approximately 13-fold increase in miR-140-5p expression compared to lymph node-negative tissue (p = 0.
049).These findings suggest that miR-140-5p, but not miR-193b, could be an important determinant of IGFBP5 expression Exteriors and clinical phenotype in breast cancer patients.Further studies are needed to clarify the expressional regulation of IGFBP5 by miR-140-5p.