Eight (22%) tumors were associated with underlying NF-1 disorder and 5 (14%) tumors (initial diagnosis: nasopharyngeal squamous cell carcinoma, n = 1; seminoma, n = 2; leukemia [total body irradiation], n = 1; and medulloblastoma [craniospinal irradiation], n = 1) were believed to be radiation induced because of the close proximity of the tumor with the previous radiation fields. This evidence concerns the gene NF1 and medulloblastoma.