MUTATIONS OF THE PATCHED GENE IN SEVERAL TYPES OF SPORADIC EXTRACUTANEOUS TUMORS

Patients with basal cell nevus syndrome have a high incidence of multi ple basal cell carcinomas, medulloblastomas, and meningiomas. Because somatic PATCHED (PTCH) mutations have been found in sporadic basal cel l carcinomas, we have screened for PTCH mutations in several types of sporadic extracutaneous tumors. We found that 2 of 14 sporadic medullo blastomas bear somatic nonsense mutations in one copy of the gene and also deletion of the other copy. In addition, me identified missense m utations in PTCH in two of seven breast carcinomas, one of nine mening iomas, and one colon cancer cell line. No PTCH gene mutations were det ected in 10 primary colon carcinomas and eighteen bladder carcinomas.