These genes were subsequently subjected to a COX risk model analysis, which identified 26 risk genes significantly associated with melanoma progression: PPP1R13L, S100A9, S100A8, PERP, TP53AIP1, PLD2, WNT3A, EFNA3, SFN, PLA2G4D, PLA2G4F, PLA2G4E, PLA2G2F, WNT3, S100A7A, CALML5, WWC1, CALML3, PAK6, DEFB4A, DEFB4B, and TEAD3. This evidence concerns the gene PLD2 and melanoma.