Detection of C-erb B2 gene amplification in bilharzial associated bladder cancer using fluorescence in situ hybridization

BACKGROUND: Gene amplifications are common events in different tumor types and may confer diagnostic, prognostic, or therapeutic information for patient management. Fluorescence in situ hybridization (FISH) represents a standard methodologic approach for testing for this genetic alteration, as it is rapid, reproducible and extremely reliable in detecting presence of C-erb-B2 gene amplification for clinical utility. PATIENTS AND METHODS: In this study, FISH is used in a series of archival human bilharzial bladder cancer specimens to evaluate for the presence of cerbB-2 gene alterations in the most common malignant tumor in bilharzial endemic areas, e.g., Egypt and some other countries. The study included 40 cases, 30 males and 10 females. Their ages ranged between 30 years and 76 years (median: 51 years). Twenty-one cases had squamous cell carcinoma, 16 had transitional cell carcinoma, two had adenocarcinoma, and one case had undifferentiated carcinoma. RESULTS: Thirteen out of 40 tumor samples (32.5%) show evidence of true C-erb-B2 gene amplification. Of the remaining samples, 24 (60%) show no gene amplification and three (7.5%) fall into the borderline category with a ratio between one and two C-erb-B2 genes/cell relative to chromosome 17 centromeres. No evidence of chromosome 17 polysomy was found in any cases scored as single copy with the C-erb-B2 probe. CONCLUSION: No significant association was found between gene amplification and any of the tested clinicopathologic parameters or tumor recurrence except for tumor grade where higher tumor grades tended to be associated with more C-erb-B2 gene amplification (P = 0.01) thus reflecting more tumor aggressiveness. So, the amplification of C-erb-B2 in bilharzial associated bladder cancer is probably not independently related to clinical outcome of patients.