IGFBP2 and melanoma: To evaluate whether SIRT6 and IGFBP2 levels anti-correlate in human melanoma tissues, we performed SIRT6 IHC on 21 BRAFV600E/K melanomas stained for IGFBP2, and observed a statistically significant inverse correlation (Spearman’s r = −0.462; P = 0.035; Fig. 5d, e).