Transforming growth factor-beta (TGFB; MIM.190180) inhibits cell proliferation by inducing a G1-phase cell cycle arrest.
Normal progression through G1 is promoted by the activity of the cyclin-dependent protein kinases CDK4 (MIM.123829) and CDK6, which are inhibited by the protein p16(INK4) (CDKN2A; MIM.600160).
Pathology
Cytogenetic abnormalities at 9p21 are common in many types of human tumors.
CDKN2B is frequently and differentially methylated in ependymal tumours. (14636164)