Loss of heterozygosity at chromosome segments 8p22 and 8p11.2-21.1 in transitional-cell carcinoma of the urinary bladder

To identify the putative tumor-suppressor gene (TSG) involved in transitional-cell carcinoma (TCC) of the urinary bladder, we undertook an allelotyping analysis in 48 cases of TCC. Relatively high percentages of allelic loss were found in 2p (5 of 23, 21.7%), 8p (9 of 21, 42.9%), 9p (4 of 20, 20.0%), 12q (6 of 28, 21.4%), 15q (1 of 5, 20%; 4 of 20, 20%), 17p (7 of 26, 26.9%) and 22q (6 of 23, 26.1%). On the basis of these results, fine-deletion mapping was performed on chromosome 8 in 52 cases by PCR of 15 microsatellite markers. Two distinct regions of common deletion were found. A 10 cM telomeric region was located to 8p22, defined by D8S511 and D8S258. A 17 cM centromeric region was located to 8p11.2-21.1, flanked by D8S298 and D8S535. The distance between the telomeric and the centromeric regions of common deletion was 3 cM. Loss of heterozygosity of 8p22 was frequently observed in tumors of high grade or advanced stage.