Mutations in the DNA mismatch repair genes, such as MLH1 (human mutL homolog 1) [24,25] and MSH6 (human mutS homolog 6), have been reported in NF1 cases with malignant lymphoma (as shown in Table 1), early-onset CNS tumors, and colorectal cancer [31]. This evidence concerns the gene MLH1 and neurofibromatosis type 1.