Molecular Genetic Alteration and Loss of Genes on the Short Arm of the Chromosome 11 in Bladder Tumor

Kim, Bup Wan; Kim, Heung Ki; Chung, Woon Bok; Kim, Jung Wan

Abstract

Although bladder transitional cell carcinoma (TCC) is common, the underlying molecular events remain ill-defined. So we attempted to define the role of tumor suppressor genes in the pathogenesis of bladder tumor through a molecular genetic study. For 15 bladder TCC (6 gradeII, 1 gradeIII, and 8 grade IV), we performed the restriction fragment length polymorphism (RFLP) analysis for 6 loci of suspected or established tumor suppressor regions (3p21, 3p24-25, llp15, 13q14, and 17p13). Our data confirm that allelic losses are highly common in bladder tumors. We found that alleles from each of the four chromosomal arms tested were lost in most of the tumors. Reduction of allele occured at 3p21 (13%), 3p24~25 (50%), and 13q14 (38%). However, the greatest frequency of allelic loss was seen for 17p 13 (100% of informative cases) and llp15.5 (87% informative cases). Severe allelic losses of chromosome 17p and pADJ762 on lip were seen only in grade IV, not in grade II. Amplification of 3p21 was seen six out of eight. Amplification of 3p21 has not been previously observed on the other study. Addition to this, we observe the loss of H-ras allele on 11p in one case which was associated with duplication of the retained allele as was demonstrated in Wilms'tumors. The results of out study suggest that deletions of pADJ762 on chromosome 11p and 17p13 occur in high grade bladder tumor and may contribute to the progression of this disease. But, there was no apparent correlation between tumor grade and the loss of 3p or 13q14 alleles although they had some deletions. The role of these genetic alterations in the prognosis of bladder transitional cell carcinoma will require additional follow-up and further studies.