KRAS and skin squamous cell carcinoma: Next, we examined a further cohort of 30 primary cSCC samples with matched normal tissue (Supplementary Table 4) employing next-generation WES (see Methods) and interrogated in detail NOTCH1, NOTCH2, TP53, CDKN2A, HRAS, KRAS, NRAS, TGFBR1 and TGFBR2 genes for mutational and copy number changes (Fig. 2a and Supplementary Data 7).