Serum level of soluble interleukin-2 receptor α (sIL-2Rα) has been shown to correlate with disease progression and prognosis of cancer patients. However, the available information about the source and the pathophysiological regulation of IL-2Rα in cancer cells is limited. This study addressed the questions of prognostic value and the source of sIL-2Rα in patients with nasopharyngeal carcinoma (NPC). Biological regulation of IL-2Rα was characterized in NPC cell lines. Serum sIL-2Rα levels of 113 NPC patients were measured by enzyme-linked immunosorbent assay (ELISA). Levels of sIL-2Rα in NPC patients were significantly higher than that in the healthy controls, and sIL-2Rα levels were correlated with disease progression and patient survival. IL-2Rα was identified in cancer cells by immunocytochemistry. In vitro, IL-2Rα expression was markedly increased following treatment with platelet activating factor and/or n-sodium butyrate. Increased secretion of IL-2Rα was also detected in the culture media. The secreted IL-2Rα could functionally bind IL-2. These results indicate that elevated sIL-2Rα was often detected in patients with advanced NPC. The elevated sIL-2Rα could be shed from NPC cells by a yet to be determined mechanism and IL-2Rα expression in NPC cells could be upregulated by platelet activating factor and butyrate.

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