ERCC1 and xeroderma pigmentosum: This analysis revealed that the XP-C tumor mutational profiles and their NMF-derived mutational Signature “C” had the highest similarity to the COSMIC Signature 8 (cosine similarity of 0.87−0.92, and 0.86 respectively) and formed a cluster together with XPC and Ercc1 organoid knockouts (Fig. 2c and Supplementary Fig. 2e).