ABSTRACT: Loss of Heterozygosity on Chromosome 9q and p53
Alterations in Human Bladder Cancer

In the U.S., approximately 60,000 new cases of bladder cancer occurred in 2004.1 Carcinoma of the urinary bladder tends to present as a super.cial, lower-stage and lower-grade tumor at the time of diagnosis.2 These noninvasive tumors can be removed by transurethral resection and tend to have a signi.cantly higher survival rate.3 Most early-stage bladder cancers remain super.cial and noninvasive for extended periods. However, after surgical removal some patients develop one or more recurrences and there is a persistent risk that these tumors could invade the muscular walls of the bladder and become life threatening.4,5 Developing molecular markers that de.ne these at-risk lesions is clinically important for prognosis and improved treatment. Alterations of the p53 gene are some of the most frequently
documented somatic alterations in human bladder cancer, as well as other tumor types, and detection of this altered gene holds prognostic signi.cance. Several studies, including our own, have clearly shown that inactivation of the p53 pathway is prevalent in this disease, and that its aberrant immunohistochemical staining correlates with the degree of invasiveness of the tumor.6,7