MicroRNA Expression of Primary and Metastatic Colorectal and Breast Carcinoma

Abstract

Background: Colorectal and breast carcinoma are frequently diagnosed cancers. At advanced stages, cancers metastasize to certain organs resulting in loss of function of these organs, and eventually death. Therefore, there is a specific need for the prognosis of these cancers. Currently, microRNAs (miRNAs), have emerged as a new target of cancer-specific biomarker. Objective: To examine the expression of miRNA in primary and metastatic breast and colorectal cancers. Methods: This study investigated the expression of 6 miRNAs (miR-10b, miR-21, miR-145, miR-155, miR-200c, and miR-373) in formalin fixed paraffin embed tissues from pairs of normal tissues with primary and metastatic tumor samples of breast and colorectal carcinoma cases in Ramathibodi Hospital, Thailand by real-time RT-PCR. Results: Among 6 miRNAs, miR-145 decreased significantly in all samples of primary and metastatic colorectal and breast carcinoma. There was significantly decreased expression of miR-145 in metastatic colorectal carcinoma compared to their primary colorectal carcinoma (P < .05). Whereas miR-10b, miR-155, and miR-200c showed a decreased expression; miR-21, and miR-373 showed an increased expression in the majority of cases. Unlike miR-145, other miRNAs showed no significant difference of expression (P > .05). Conclusions: This finding indicates that miR-145 may be the potential metastatic biomarker. Decrease of miR-145 could be applied to the prognosis and target for therapy of breast and colorectal carcinoma.