Previous studies have shown a lack of cutaneous squamous 17-DMAG FDA cell carcinoma immune-histochemical staining by Ber-EP4 (11�C15). Our study found that 8/9 (89%) cases of squamous cell carcinoma did not stain for the epithelial antigen Ber-EP4. However, one case demonstrated focally positive basal layer staining. Epithelial specific antigen clone VU-1D9 did not stain 7/9 cases (78%), but stained one case focally positive and one case diffusely positive. Other authors have reported negative staining of squamous cell carcinoma in situ with epithelial antigen clone Ber-Ep4. Tope et al showed 8/8 cases of squamous intraepithelial neoplasia to be negative for Ber-EP4 staining; this was recapitulated by Ansai et al in 10/10 cases.
16,17 Consistent with these reports, the present study found that 7/7 cases of Bowen��s disease did not stain immune-histochemically for epithelial antigen clone Ber-EP4. However, 3/7 cases stained for epithelial specific antigen clone VU-1D9, with focal positive staining in the lower half of the epidermis. Thus, this anti EpCAM antibody, derived from a small cell lung carcinoma cell line (HG9) may be less specific for basal cell carcinoma. This focal positive staining pattern using antibodies to Epithelial specific antigen (VU-1D9) may represent a potential diagnostic pitfall. Consistent with our findings, previous investigators have described positive epithelial antigen immune-histochemical staining of basal cell carcinomas in all (100%) samples studied.
11�C14,16,18�C22 Most recently, Ansai et al reported two studies with slightly lower Ber-EP4 positivity seen in basal cell carcinoma, the first with 8/10 (80%) positive, and the second with 30/31 (97%) positive.15,17 All trichoepitheliomas stained diffusely positive for both epithelial antigens studied. This finding is consistent with previous reports of Ber-EP4 positivity in follicular neoplasms such as trichoepithelioma.12,13,17�C19,22 and trichoblastoma.17,23 Thus, these lesions are not reliably differentiated using the monoclonal antibodies studied and their diagnosis relies heavily on microscopic features. Our study also confirmed the previously reported staining of merkel cell carcinomas.12 Our study confirmed findings by Ansai et al,17 which showed no immune-histochemical staining of these epithelial antigens within seborrheic keratoses.
Actinic keratoses included in our study failed to stain for EpCAM with both antibodies studied, which is consistent with previous reports.16,17 Our study found that immune-histochemical staining for monoclonal antibodies to Epithelial Antigen clone Ber-EP4 may be more specific for basal cell carcinoma than that of Epithelial-specific antigen clone VU-1D9. Out of 112 cases, Drug_discovery the former stained 100% of basal cell carcinomas, merkel cell carcinomas, and trichoepitheliomas, and did not stain 97% (74/76) of other skin lesions.