RIZ, the retinoblastoma protein interacting zinc finger gene, is mutated in genetically unstable cancers of the pancreas, stomach, and colorectum

The retinoblastoma protein interacting zinc finger (RIZ) gene is a candidat e tumor suppressor gene on 1p36, a region frequently rearranged in a wide v ariety of human tumors. As the RIZ gene harbors several microsatellites wit hin its coding region, it is a candidate for an inactivating mutation in mi crosatellite instability (MSI) mediated carcinogenesis. In this study, we e xamined mutations of two poly adenine tracts, A(8) and A(9), within the cod ing region of the RIZ gene, in MSI-high (MSI-H) primary cancers occurring i n the pancreas, stomach, and colorectum. Frameshift mutations were found in one (10%) of 10 pancreatic, four (35%) of 11 gastric, and two (25%) of eig ht colorectal cancers. These results indicate that mutations of the RIZ gen e play an important role in the pathogenesis of some MSI-H cancers. (C) 200 1 Wiley-Liss, Inc.