Role of interleukin-1alpha and type I interleukin-1 receptor in the growth activity and invasion of gastric carcinoma cells.

To clarify the role of the interleukin (IL)-1/IL-1 receptor system in the progression of gastric carcinoma cells in patients with advanced gastric cancer, we measured the tissue concentrations of IL-1alpha, the expression of IL-1-receptor type I (IL-1RtI) on tumor cells, and the cell-growth activity through an analysis of DNA content. The concentrations of IL-1alpha were significantly higher in differentiated than in undifferentiated tumors (P = 0.038). The expression of IL-1RtI was upregulated in the tumor cells associated with INFgamma [corrected], scirrhous type tumors, and T3 and T4 tumors. There was a clear linear correlation between the tissue concentrations of IL-1alpha and S-phase fractions in differentiated tumors (r = 0.664, P = 0.003). Tumor cells with high IL-1alpha concentrations and low IL-1RtI expression had significantly greater S-phase fractions than those with low IL-1alpha concentrations, independent of IL-IRtI expression (P = 0.024 in low IL-1RtI, P = 0.019 in high IL-IRtI). These findings indicate that IL-1alpha stimulates the growth of differentiated gastric carcinoma cells and that IL-IRtI expression is involved in tumor invasive activity. High S-phase levels were not necessarily associated with a high expression of IL-1RtI, which may be due to the downregulatory effects of high IL-1alpha concentrations.