Comparison of immunohistochemical (IHC) staining for BerEp4 and MOC31 in Bowen Disease (BD)

Abstract Introduction/Objective Ber-EP4 and MOC31 are antibodies that target the epithelial cell adhesion molecule (Ep- CAM). In dermatopathology, BerEP4 IHC is classically used to differentiate between basal cell carcinoma (positive) and primary squamous cell carcinoma of the skin (negative). BerEP4 also stains pagetoid tumor cells in Paget Disease (PD), and can be used as part of a panel to assist in differentiating Paget Disease (positive) and Bowen Disease (presumed negative). However, a published abstract reported the unexpected finding that some cases of BD can stain variably positive for BerEP4, a potential pitfall. This finding was subsequently reported in several publications. Recently, MOC-31 has been proposed to be superior to Ber-Ep4 for use in Mohs surgery on basal cell carcinoma. We investigated whether MOC-31 might also show less positivity than Ber-Ep4 in BD, which would be helpful in the context of BD vs. PD. Methods/Case Report Biopsy samples from 20 cases of Bowen Disease were examined immunohistochemically with BerEP4 and MOC31. Results (if a Case Study enter NA) In Bowen Disease, we found significant BerEP4 positivity (14/20) compared to MOC31 (5/20). Conclusion MOC31 shows less frequent staining of BD than Ber-Ep4, which enhances its utility in a BD vs. PD panel.