Epidermal growth factor receptor (ErbB1) expression in prostate cancer progression: Correlation with androgen independence

Abstract

BACKGROUND The role of the epidermal growth factor receptor (ErbB1) in the progression of prostate cancer is incompletely understood. METHODS Tissue microarrays from hormone-naive and advanced androgen-independent tumors were used to investigate the role of ErbB1 in prostate cancer progression. RESULTS ErbB1 expression in tumor tissues was strongly associated with hormone-refractory status (odds ratio = 6.67, 95% CI = (2.6, 17.4), P = 0.0001). However, ErbB1 overexpression was not a statistically significant covariate in a multivariate proportional hazards model for biochemical failure of hormone-naÏve prostate cancer. Moreover, ErbB1 overexpression was not associated with tumor differentiation ( P = 0.44), positive margins ( P = 0.53), seminal vesicle invasion ( P = 0.69), extraprostatic extension ( P = 0.10), or preoperative PSA ( P = 0.18) in the hormone-naÏve group. CONCLUSIONS These findings are consistent with a model in which ErbB1 expression increases during the development of the androgen-independent state, and suggest that drugs targeted toward ErbB signaling could be of therapeutic relevance in the management of advanced prostatic carcinoma. Prostate 66: 1437–1444, 2006. © 2006 Wiley-Liss, Inc.