PIK3CA and breast carcinoma: In breast cancer, high expression of the hsa-miR-26a miRNA downregulates EZH2 and is therefore related to a favorable outcome on tamoxifen in metastatic breast cancer [41], and also interacts with CDK4 and CENTG1 oncogenes and forms an integrated oncomir/oncogene DNA cluster, which promotes glioblastoma tumor growth via RB1, PI3K/AKT, and JNK pathways [39].