p16 involvement in primary bladder tumors: Analysis of deletions and mutations

Different studies have proposed that genetic alterations leading to inactiv ation of a tumor suppressor gene on chromosome 9 is an important early even t in bladder tumorigenesis. Recent reports have described the p16 gene as t he main target. In order to better define its role, we studied 9p21 deletio ns by microsatellite analysis and its coding sequence. Forty-eight percent of the 44 samples we studied showed LOH surrounding p16. Three of these 44 samples displayed point mutations in p16 and three others were suspected of homozygous deletion. These results suggest that simultaneous loss of both p16 alleles, by point mutation or homozygous deletion, seems to be infreque nt in bladder tumors.