Clinicopathological and Targeted Exome Gene Features of a Patient with Metastatic Acinic Cell Carcinoma of the Parotid Gland Harboring an ARID2 Nonsense Mutation and CDKN2A/B Deletion

Figure 3

The CDKN2A-CDKN2B locus regulates the cell cycle. Genomic organization of the 9p21 locus containing CDKN2B encoding and CDKN2A encoding and . is coded by exons E1β, E2, and E3 and is coded by exons E1α, E2, and E3. E2 and E3 are shared by and , but they use alternate reading frames to produce unique protein sequences. and induce cell cycle arrest by complexing to CDK4 and CDK6 and preventing their complex formation with cyclin D. Rb remains active (dephosphorylated) and prevents E2F-mediated transcription of target genes necessary for cell cycle progression from G1 to S phase. inhibits cell cycle progression and activates apoptosis by inhibiting MDM2, which leads to activation of p53.