HER-2/neu expression in Paget disease of the vulva and the female breast

Abstract

Objectives. Paget disease of the vulva is a rare lesion that accounts for <1% of vulva neoplasms. A 12% prevalence of invasive Paget carcinoma and a 4% prevalence of associated adenocarcinomas are described. Furthermore, a high recurrence rate of 30% after surgical therapy is observed. This study aims to search for therapeutic strategies for recurrent Paget disease, which are less mutilating and less aggressive than reexcision, x-ray therapy, or chemotherapy. Trastuzumab (Herceptin™) is a recombinant monoclonal antibody against HER-2/neu, approved by the U.S. FDA for the treatment of patients with HER-2/neu-positive metastatic breast carcinomas. The results of recent studies indicate that HER-2/neu oncoprotein may play a role in the pathogenesis of extramammary Paget disease. Methods. Using HercepTest™, we analyzed HER-2/neu overexpression in seven noninvasive Paget lesions, two invasive lesions, and one Paget disease of the vulva with underlying adenocarcinoma. In addition, we investigated five mammary Paget diseases. Results. Overexpression of HER-2/neu oncoprotein labeling exclusively the membranes of Paget cells was demonstrated in 8 out of 10 cases. One noninvasive and one with underlying adenocarcinoma stained negatively. Overexpression of HER-2/neu was demonstrated in all five cases of mammary Paget disease. Conclusion. Using HercepTest™ as a standardized detection system, overexpression of HER-2/neu can be demonstrated in a majority of both noninvasive and invasive Paget disease of the vulva. The use of Trastuzumab should be considered for the treatment of patients with recurrent Paget disease of the vulva with overexpression of HER-2/neu.