The Significance of MicroRNA Let-7b, miR-30c, and miR-200c Expression in Breast Cancers

Abstract

Background: MicroRNA (miRNA) is a class of noncoding protein RNA as a promising biomarker for various diseases. In this study, the expression of let-7b, miR-30c, and miR-200c was studied in breast cancer tissues to evaluate the potential relationship with known clinicopathological parameters. Methods: Quantitative real-time polymerase chain reaction was performed to determine the expression level of three miRNAs in 37 pairs of noncancerous normal and cancer tissues and an additional 38 cancer tissues from patients with invasive ductal carcinoma. Results: miR-200c expression was higher in cancer tissues compared to noncancerous normal tissues, and its ratio was correlated with patient age at surgery, type of surgery, and Ki-67 expression. The expression level of let-7b in cancer tissues was inversely correlated with lymph node metastasis, histological grade, and Ki-67 expression but positively correlated with estrogen and progesterone receptor expression. miR-200c expression level was positively correlated with Her-2 expression. The miR-30c expression level in breast cancer was not correlated with any parameters. Conclusions: miR-200c and let-7b could be used as biomarkers in patients with breast cancer, but its pathological mechanism should be determined.