Immunohistochemical expression of HER2 in urothelial bladder carcinoma and its correlation with p53 and p63 expression

This study assessed the human epidermal growth factor receptor-2 (HER2) protein expression in urothelial bladder carcinoma and its relationship with p53 and p63 expression. In 151 patients, paraffin-embedded tissues of transurethral resection or cystectomy were evaluated by immunohistochemistry (IHC), using antibodies against HER2, p53 and p63. HER2 overexpression (score 3+), p53 overexpression and decreased expression of p63 were detected in 14 (9.3%), 48 (31.8%) and 58 (38.4%) tumors, respectively. HER2 overexpression, p53 overexpression and decreased expression of p63 were associated with high tumor grade (p = 0.0002, p = 0.0002 and p = 0.046, respectively) and advanced TNM stage (p = 0.017, p = 0.012 and p = 0.001, respectively) of urothelial bladder carcinoma. In univariate analysis HER2 overexpression was significantly associated with decreased expression of p63 (p = 0.037). In multivariate analysis, only tumor grade was correlated with HER2 overexpression (p = 0.006). In this study, HER2 is overexpressed in 9.3% of urothelial bladder carcinomas. HER2 overexpression was strongly correlated with tumor grade but not with TNM stage, p53 and p63. The development of target therapies using anti-HER2 and the identification of patients which who benefit from those therapies need further studies.