Effect of interleukin-2 and selenium on the growth of squamous cell carcinoma cells

OBJECTIVES: The objectives of this study were to determine whether the expr ession of the interleukin-2 (IL-2) receptors on squamous cell carcinoma cel ls can be enhanced in the presence of selenium (Se) and contribute to a gre ater retardation of tumor growth after lacoregional therapy with IL-2. STUDY DESIGN: The growth of the cells was studied after in vitro or dietary supplementation with Se in a murine model. RESULTS: Treatment of established tumors in hosts supplemented with Se with peritumoral injections of IL-2 resulted in 50% reduction of tumor size, wh ereas treatment of early tumors resulted in 72.4% reduction. The effect was most likely related to a combination of enhanced immune responsiveness and : enhanced IL-2 receptor expression on the tumor cells. CONCLUSIONS AND SIGNIFICANCE: The data suggested that local immunotherapy w ith IL-2 in hosts supplemented with Se may represent an effective modality of treatment for the prevention of recurrences at the site of conventionall y treated primary tumors, including tumors that do not express IL-2 recepto rs.