Immunohistochemical localization of interleukin-10 in human oral and pharyngeal carcinomas.

OBJECTIVES/HYPOTHESIS: Interleukin-10 (IL-10) is an immunosuppressive cytokine with numerous, well-described effects on the human cellular and humoral immune response. The oncogenic potential of IL-10 has been previously investigated in bronchogenic carcinoma, nasopharyngeal carcinoma, Waldeyer's ring carcinoma, and serum supernatants of patients with squamous cell carcinoma of the head and neck (SCCHN). The purpose of the study was to determine the prevalence and cellular localization of IL-10 in human SC-CHN.

STUDY

DESIGN

Immunohistochemistry of archival tissues.

METHODS

Paraffin-embedded archival tissues were retrospectively obtained from 98 patients with oral and pharyngeal squamous cell carcinoma. Using a standard immunohistochemical technique, these specimens were stained with a polyclonal antibody to IL-10.

RESULTS

Using these methods, we found specific localization of antigenic IL-10 to individual tumor cells in 65% of tumors studied. Intensity of staining was significantly, but inversely, related to tumor grade and N stage; there also existed a significant staining predisposition for oral cavity lesions when samples from this site were compared with tissues derived from elsewhere in the pharynx. Furthermore, IL-10 was not localized to normal epithelial keratinocytes or inflammatory cells at the level of sensitivity achieved by the immunohistochemical methods used in the study.

CONCLUSIONS

The findings demonstrate that IL-10 can be specifically localized to human oral and pharyngeal cancer cells. These data also suggest an inverse association for both tumor grade and N stage with specific tumor marker staining. Future studies should investigate the role of this cytokine in the pathogenesis of human SCCHN.