PCLAF and skin neoplasm: Ultraviolet (UV)-mediated immunosuppression poses a major risk for skin cancer induction,1, 2 and many have reported that an essential mediator in this process is UV-induced platelet-activating factor (PAF; 1-alkyl-2-acetyl-sn-glycero-3-phosphocholine).3, 4, 5 PAF is a phospholipid, first discovered as a secreted component by activated innate immune cells,6, 7 that mediates its activity by binding to a G-protein-coupled receptor.8 It is involved in a variety of mechanisms including the release of histamine in activated leukocytes,9, 10, 11 anaphylaxis, and phagocytosis.12