Specificity of MOC-31 and HBME-1 immunohistochemistry in the differential diagnosis of adenocarcinoma and malignant mesothelioma: a study on environmental malignant mesothelioma cases from Turkish villages.

Histological diagnosis of malignant mesothelioma (MM) and differentiation from adenocarcinoma is often difficult. A number of clinical, radiologic, histologic and histochemical criteria have been used as diagnostic aids, but most cases cannot be readily classified on the basis of these characteristics. In recent years, a panel of immunohistochemical anti-bodies have been increasingly applied for the differential diagnosis of these two tumors. MOC-31 has been recently used as specific for adenocarcinomas while reacting with a minimal number of benign and malignant mesothelial proliferations, and HBME-1 has also been presented as a mesothelial cell marker. In this study, we aimed to show the importance of these two antibodies among the environmental MM cases from Southeastern Turkey. Fifty five cases of MM and twenty adenocarcinomas were included in this study. Histochemical (PAS, PAS-D, mucicarmine) and immunohistochemical (Keratin, EMA,CEA, MOC-31, HBME-1) stains have been performed on each case. Keratin was positive in all cases. EMA stained 50 of 55 MM and all the adenocarcinoma cases. According to our results, dPAS, mucicarmen, CEA and MOC-31 positivity was statistically significant in the diagnosis of adenocarcinoma whereas HBME-1 was demonstrable in most MM cases (52/55) and 11 adenocarcinoma cases. This study confirmed that in the diagnostic distinction between MM and adenocarcinoma, immuno-histochemistry is an important diagnostic tool, however, a panel of antibodies must be used rather than any single antibody. HBME-1 should be included in this panel; MOC-31 can be used where CEA is not available or to doublecheck the reactivity of this antibody.