B-cell antigen marker expression in nasopharyngeal carcinoma

Immunohistochemical analysis was carried out to examine the characteristics of nasopharyngeal carcinoma (NPC) using 38 biopsy cases obtained from southern China. These cases were divided into 3 groups according to their predominant pattern associated with cell and tissue differentiation which is based on World Health Organization (WHO) classification as follows: 6 cases of squamous cell carcinoma (16%), 25 cases of differentiated non-keratinizing carcinoma (66%), 7 cases of undifferentiated carcinoma (18%). All tumor tissues reacted with MB-1, but they did not react with L26 (CD20), 4KB5 (CD45R), MT-1, and leukocyte common antigen (LCA). Keratin and epithelial membrane antigen (EMA) as epithelial markers focally stained NPC tissues in all cases. Carcinoembryonic antigen (CEA)-positive staining was detected in 7 (28%) of the 25 cases of differentiated non-keratinizing carcinoma and in 3 (43%) of the 7 cases of undifferentiated carcinoma; thus, of 38 cases, 10 (26%) were CEA-positive. On the other hand, squamous cell carcinoma cases did not react with CEA. These NPC tissues did not react with S-100 protein, alpha-1-antichymotrypsin (ACT), lysozyme, vimentin, and desmin. Therefore, it is concluded that some cases of NPC are difficult to distinguish from malignant lymphoma. In certain cases, NPC may be distinguished from malignant lymphoma, using immunohistochemical methods for the detection of MB-1, keratin, EMA, and LCA. Specifically, this evidence suggests that MB-1 may be useful as a tumor marker of NPC. Moreover, the CEA reaction to NPC may be related to the cell differentiation.