In agreement with our results with melanoma cell lines, the level of pSer33/37-Thr41 β-catenin, targeted for proteasomal degradation, is largely unaltered in NRAS-ΔPTEN compared with NRAS. Conversely, the amount of total and pSer675 β-catenin, corresponding to the transcriptionally active form of β-catenin, is significantly higher in NRAS-ΔPTEN compared with NRAS. Consequently, we reproducibly observed a reduction of p16INK4A protein in NRAS-ΔPTEN as compared with NRAS. This evidence concerns the gene CDKN2A and melanoma.