Immunoreactive myelin basic protein in tumor cells associated with carcinomatous neuropathy.

Tumors from two patients with carcinomatous neuropathy were studied with an immunohistochemical method using anti-myelin basic protein (anti-MBP) sera. In both cases, immunoreactive MBP was clearly demonstrated in some of the tumor cells, which were widely distributed either singly or, more often, in clusters. The staining intensity varied from cell to cell. An autoimmune mechanism to nervous elements has been suggested in the pathogenesis of carcinomatous neuropathy. MBP is known to be a highly specific and potent antigen that can induce allergic neuritis in animals. In one patient the progressively worsening neurologic condition rapidly improved after gastrectomy removed the carcinoma. It is possible that immunoreactive MBP in tumor cells may function as an "antigen" in the development of carcinomatous neuropathy.