Evaluation of HER2 protein overexpression in non-muscle invasive bladder cancer with emphasis on tumour grade and recurrence

Abstract

ObjectiveTo evaluate the prognostic value of HER2 expression in non-muscle invasive transitional cell carcinoma (TCC) of the bladder with special emphasis on the high-grade population. Materials and methods (patients)We performed tissue microarrays (TMA) with representative TUR-B specimens from 84 patients with non-muscle invasive transitional cell carcinoma (TCC) of the bladder (40 pT1GII and 44 pT1GIII) treated at our institution. The same pathologist who performed blind immunohistochemical analysis with Hercep test uniformly assigned depth of invasion and grade: 3+ was considered strong positive HER2 overexpression. We also assessed other clinico-pathological variables. ResultsWe detected HER2 protein overexpression in 30/44 (68.2%) pT1GIII lesions and predicted recurrence in this subgroup of bladder TCC (p<0.01). We detected negative HER2 expression in 26/40 (65%) cases with pT1GII TCC, and this condition was more frequent in unifocal tumours, without angiogenesis, with a low recurrence rate and without progression. Recurrence-free survival can also be anticipated by HER 2 expression within pT1GII tumours (p<0.01). ConclusionHER2 expression using Hercep Test™ may be useful to predict recurrence in non-muscle invasive bladder TCC. The potential application of this study, especially regarding prediction of response to BCG, should be prospectively confirmed in multiinstitutional trials.