IMMUNOLOCALIZATION OF INTERLEUKIN-6 IN SALIVARY-GLAND TUMORS

Interleukin-6 (IL-6) is a multifunctional cytokine that regulates immu ne responses and acute phase reactions. It has demonstrated a growth f actor function in several tumors, including those of salivary, plasma cell, and renal origin. We performed immunohistochemical staining for IL-6 localization on 57 salivary tumors. Reactivity was scored by inte nsity (0 to 4+) and percentage of cells staining and the tumors were c lassified into three groups representing low (0 to 1+, 0% to 30%), mod erate (2 to 3+, 31% to 75%), or high (>3 to 4+, 76% to 100%) reactors. High reactivity was found in all primary pleomorphic adenomas (N = 10 ), five of eight recurrent pleomorphic adenomas, and all polymorphous low grade adenocarcinomas (N = 4). Moderate reactivity was observed in four of seven basal cell adenomas and three of five myoepitheliomas. Low reactivity characterized all acinic cell carcinomas (N = 3) and mu coepidermoid carcinomas (N = 3) as well as six of nine primary adenoid cystic carcinomas and all metastatic adenoid cystic carcinomas (N = 3 ). Carcinoma ex pleomorphic adenoma (N = 5) had three low and two mode rate reactors. A pattern emerged in which the benign and low grade mal ignant tumors showed stronger reactivity than the metastatic or high g rade malignant tumors. This suggests an inverse relationship between t he presence of IL-6 and the biological aggressiveness of salivary glan d tumors. The function of IL-6 in salivary gland neoplasia awaits furt her study and elucidation. Copyright (C) 1995 by W.B. Saunders Company