CCNA2 and cancer: But CDK2 hyperactivation in human cancers is most often associated with amplification and/or overexpression of its partner cyclins A and E in a wide variety of human cancers, but in particular in breast cancer, ovarian and endometrial carcinomas, lung and thyroid carcinoma, melanoma and osteosarcoma [129,131,143,147,148,149,150,151,152,153,154,155,156,157,158].