CDKN2A and melanoma: In addition to Ras, a GTPase, first established to induce OIS by Serrano et al. [60], and later became the most frequently utilized oncogene to induce senescence experimentally, others have demonstrated that B-Raf, a serine/threonine-protein kinase, can induce a p16INK4a-driven senescent growth arrest in cells found in Spitz nevi (benign melanocytic precursors for melanoma) [10,127].