We note that a small subset of samples showed higher mutation burdens, with 11 acral and 2 mucosal melanomas having over 10 mutations per megabase, attributable to UV radiation (SBS7; n = 8), chemotherapy with temozolomide (SBS11) and/or platinum (SBS31) (n = 4), or DNA mismatch repair defects (SBS 21 and 26) due to homozygous deletion of MLH1 in A_MELA_0271 (MSI score = 20.59) (Additional file 2: Figs. S4 and S5). Here, MLH1 is linked to melanoma.