MicroRNA microarray identifies a miRNA signature to predict chemotherapy response in breast cancers

To identify miRNAs involved in drug resistance of human breast cancer, a miRNA microarray was performed on 10 cases of drug resistant tissues and 10 cases of drug sensitive tissues. There were 29 differentially expressed miRNAs between drug resistant and drug sensitive tissues, including 22 significantly up-regulated and 7 down-regulated RNAs in drug resistant tissues compared to drug sensitive tissues. A signature of five miRNAs, including miR-23a-3p, miR-200c-3p, miR-214-3p, miR-638, and miR-451a was established. A risk score from the miRNA signature was calculated and patients were classified into high-risk and low-risk groups. Compared with the patients with low-risk scores, the patients with high risk scores showed resistant response to chemotherapy in the training, internal testing and independent sets. Group 1: Examination of miRNAs in drug resistant tissues (10 cases), including C22, C28, C29, C100, C142, C149, C151, C153, C173, and C178. Group 2: Examination of miRNAs in drug sensitive tissues (10 cases), including H8, H15, H19, H20, H31, H32, H80, H131, H135 and H170.