Isoantigens A, B, H(O) in nasopharyngeal carcinoma

Fifty cases of nasopharyngeal carcinoma (NPC) and its metastasis in ten lymph nodes were studied for specific red cell adherence (SRCA) to determine if any loss of blood group isoantigens was present to explain some of the differences such as their preponderance in local Chinese population and variable clinicopathologic behavior. While a patchy positive SRCA was noted on the surface of tumor cells in all cases of NPCs, it was not so in any of their metastasis. The findings suggest that in NPCs a few tumor cells may be capable of partially retaining isoantigens, and that this is neither influenced by their histologic type nor in any way seems to account for the variable prognosis. While the exact mechanism for negative SRCA in metastatic deposits in lymph nodes is unknown, it is possible that metastatic tumor cells may have lost isoantigens on reaching lymph nodes. The remote possibility of a 'preferential discharge' of isoantigen-free tumor cells from the primary tumor seemed unlikely in view of a mildly positive SRCA in all the NPCs.