Furthermore, analysis of primary breast tumors (BRCA) in The Cancer Genome Atlas (TCGA) revealed that deletion of hsa-mir-23a correlates with increased copy number of 1q12-21 in primary tumors and associates with copy gain and increased expression of the drug- resistant oncogene CKS1B. Consistent with these observations, miRNA inhibitors reduced breast cancer cell response to cisplatin. This evidence concerns the gene CKS1B and breast cancer.