CDK4 and osteosarcoma: The signal transduction pathway involved 14 genes namely CCND1, CDK4, VEGFA, CDKN2A, SRC, CHEK2, ERBB2, CD44, CCNE1, PLK1, CDC6, AURKA, CCNB2, and TNFSF11. It has been reported that patients suffering from Osteosarcoma cells develop resistance toward the kinase inhibitor drug, Sorafenib due to the mTOR signaling pathway.