Increased Circulating Myeloid- Derived Suppressor Cells and S100A8 Correlate with Clinical Stage in Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is a squamous epithelial cancer arising from the lateral wall surface of nasopharynx, shows a clear regional and racial prevalence. Developments of tumors are influenced by many factors, generally an interaction between genetic, environmental, and immune system. There is a role of myeloid derived suppressor cells in the process of immune suppression. The presence of MDSC has been described in the peripheral blood and tumors of patients with various forms of cancers. MDSC are able to strongly promote tumor progression by inhibiting anti-tumor immune responses by multiple mechanisms. S100A8 proteins are elevated in inflammation and cancer and are chemotactic; they may contribute to the recruitment and retention of MDSC. MDSC not only have receptors for S100A8/A9, but also synthesize and secrete these proteins, providing an autocrine pathway for MDSC accumulation. The aim of this study is to analyze the expression of MDSC (through CD14 and CD15 genes) and S100A8 gene in relation to clinical stage in nasopharyngeal carcinoma. Peripheral blood specimen and biopsy from primary tumor were collected from 16 nasopharyngeal carcinoma patients. The samples collected undergone RNA isolation and qRT-PCR examination. The Data were analyzed by 2-ΔΔCt method and statistical analysis. MDSC and S100A8 genes were expressed in blood higher than in tumor tissue. MDSC and S100A8 expression in nasopharyngeal carcinoma blood were significantly high correlated to clinical stage (r=-0.879, p=0.000 for MDSC; r=-0.791, p=0.0000 for S100A8). The MDSC expression also correlated with age (p=0.002), T classification (p=0.003), N classification (p=0.006), and clinical stage (p=0.001). The S100A8 expression correlated with age (p=0.041) and T classification (p=0.022). The result indicated that the high expression of MDSC was correlated with clinical stage of nasopharyngeal carcinoma especially in blood.