MLH1 and neoplasm: Other SBS signatures were identified in single tumors with a higher TMB (Fig. 2a, b), including one tumor (MELA_0271) with a mismatch repair signature (SBS21/SBS26 and ID2) due to a somatic homozygous deletion (copy number 0) affecting MLH1, and another tumor (MELA_0015) with a > 30% contribution of signature 17a/b, a signature we have also previously identified in mucosal melanoma (MM)19.