Histiocytes in nasopharyngeal carcinoma in relation to prognosis

Forty-nine biopsy specimens of nasopharyngeal carcinoma and 20 biopsy specimens of nasopharyngeal mucosa obtained from non-cancer patients were studied for the presence of T-zone histiocytes (Langerhans' cells and their precursors) and macrophages by immunohistochemical methods with the use of antibodies against S-100 protein and lysozyme (lys), respectively. Patients with dense infiltration of T-zone histiocytes in the primary sites survived longer than those without such infiltration (mean survival times, 8, 39, and 72 months in the patients with the density of -, +, and ++, respectively; P less than 0.005). In contrast, there was no relationship between patient prognosis and density of lys+ macrophages in the tumor tissue (P = 0.33). The distribution of T-zone histiocytes in the tumor tissue was different from that of macrophages. T-zone histiocytes may play an important role in the immune reaction against cancer, probably acting through mechanism different from that of macrophages.