We analyzed breast cancer dataset from TCGA and found that the levels of miR-326, miR-133a and miR-1291 were all very low, previously reported miRNAs targeting MRP1 in other cancers [18, 19] and their expression levels showed no markedly significant difference in tumors compared to their normal adjacent tissues in breast cancer (Supplementary Figure S1). Here, ABCC1 is linked to cancer.