However, six signature genes (i.e., IL8, SHC4, COL11A1, CHP2, PPP2R2C and WNT4) were not reported previously by microarray-based melanoma studies, although two (i.e. IL8 and SHC4) have been identified in independent wet-lab studies (Zhang et al., 2011; Fagiani et al., 2007; Pasini et al., 2009). This evidence concerns the gene WNT4 and melanoma.