CDK4 and liposarcoma: The solid tumors for which the CCND-CDK4/6-INK4-Rb pathway is more frequently deregulated through direct genetic, epigenetic or transcriptional modifications are breast, head and neck, lung, pancreatic, ovarian and bladder cancer, melanoma, endometrial carcinoma, liposarcoma, neuroblastoma, and malignant rabdoid tumors (3–25).