CDKN2A and neoplasm: Proteins contributing to the enrichment of these pathways are important regulators of the cell cycle, particularly cyclin-dependent kinase 1 initiating the mitotic progression65, CDKN2A also known as p16 acting as tumor suppressor through inhibition of cell cycle66, and cell cycle marker proliferating cell nuclear antigen (PCNA) also involved in DNA replication and repair67.