In addition, deletion in the gene for CDKN2A (Cyclin-Dependent Kinase Inhibitor 2A), capable of inducing cell cycle arrest in the G2 phase and apoptosis by preventing the activation of cyclin B1/CDC2 complexes, and acting as a tumor suppressor in breast cancer [60], is common in HBCX-17 and T174 cells. This evidence concerns the gene CDKN2A and breast cancer.