The protein p16, also called inhibitor of kinase 4, A (INK4A) or cyclin-dependent kinase inhibitor 2A (CDKN2A), is encoded by CDKN2A, the commonest known susceptibility gene for melanoma (Landi et al., 2020; Bennett, 2016; Castaneda-Garcia et al., 2022). The gene discussed is CDKN2A; the disease is melanoma.