ERBB2 and extramammary Paget disease: In addition, Tanaka et al. demonstrated that around 90% of patients with EMPD showed no difference in HER2 overexpression and ERBB2 gene amplification between primary lesions and lymph node (LN) metastasis, indicating that targeting therapies for HER2 may be effective for the treatment of both primary and metastatic lesions [58].