Abstract LB-219: Interleukin-8 promotes generation of M2 macrophages and arginase-producing granulocytes: Prognostic significance of interleukin-8 and infiltration of immune cells positive for CD163 and CD66b in tumor tissues in patients with oral squamous cell carcinoma

Biomarkers are essential for improving the effectiveness of treatments for patients with cancer. The immunological status in a tumor microenvironment is closely associated with the prognosis of cancer patients. Here we investigated whether serum interleukin (IL)-8 reflects the tumor microenvironment and has prognostic value in 50 patients with resectable oral squamous cell carcinoma (OSCC). We found that the relapse-free survival (RFS) was significantly longer in the Stage I/II OSCC patients with low serum IL-8 levels compared to those with high levels (p = 0.001). The tumor expression of IL-8, the infiltration of CD163-positive cells, and of CD66b-positive cells in the tumor tissues were correlated with the serum IL-8 level (p = 0.033, p = 0.038 and p = 0.044, respectively), and they were associated with poor clinical outcome (p = 0.007, p = 0.002 and p = 0.001 respectively, in DFS) in all patients. A multivariate analysis revealed that N status, tumor IL-8 expression, CD163 and CD66b infiltration significantly affected the DFS of the patients. A further analysis suggested that the combination of N status with serum IL-8, tumor IL-8, CD163 and CD66b infiltration in the tumor tissues may be a new criterion for discriminating between OSCC patients at high and low risk for tumor relapse. Finally, the in vitro experiments clearly demonstrated that IL-8 enhanced the generation of CD163-positive M2 macrophages from peripheral blood monocytes, and that the cells produced IL-10 which suppress anti-tumor immunity. Furthermore, IL-8 increased the generation of arginase-producing, CD66b-overexpressing cells from peripheral blood polymorphonuclear cells. These findings indicate that IL-8 may be involved in poor clinical outcomes via the generation of CD163-positive M2 macrophages and CD66b-overexpressing, arginase-producing granulocytes, and that these factors may have prognostic value as well as may be new targets for treatment in patients with resectable OSCC. Citation Format: Masato Okamoto, Yohei Fujita, Hiroyuki Goda, Koh-ichi Nakashiro, Hiroyuki Hamakawa. Interleukin-8 promotes generation of M2 macrophages and arginase-producing granulocytes: Prognostic significance of interleukin-8 and infiltration of immune cells positive for CD163 and CD66b in tumor tissues in patients with oral squamous cell carcinoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-219. doi:10.1158/1538-7445.AM2015-LB-219