Elevated chronic inflammatory factors and myeloid-derived suppressor cells indicate poor prognosis in advanced melanoma patients.

Chronic inflammation is considered to be one of the hallmarks for tumor initiation and progression. Moreover, a long-term production and accumulation of inflammatory factors lead to a local and systemic immunosuppression associated with cancer progression. However, the correlation between inflammatory mediators, immunosuppressive cells and the clinical outcome of malignant melanoma patients was poorly investigated. In this study, we performed a complex analysis of various inflammatory factors, myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs) in the peripheral blood of patients suffering from malignant melanoma of different stages. We demonstrated that levels of serum IL-1ß, IFN-γ and CXCL10 were significantly increased in advanced melanoma patients. In addition, these factors were found to be associated with an increased frequency of MDSCs and Tregs as compared to age- and gender-matched healthy donors. Importantly, advanced melanoma patients with signs of progression displayed markedly elevated concentrations of IL-1ß and CXCL10 as compared to patients with stable disease. Moreover, an enrichment of circulating monocytic (Mo)-MDSCs significantly correlated with a decreased progression free survival of these patients. Our data highlight a complex association between circulating inflammatory mediators, Mo-MDSCs and the clinical outcome as well as suggest that their levels in patients with advanced melanoma are of important prognostic value allowing the identification of those with high risk of disease progression.

Serum inflammatory factors and circulating immunosuppressive cells are predictive markers for efficacy of radiofrequency ablation in non-small-cell lung cancer.

In recent years, percutaneous radiofrequency ablation (RFA) has been developed as a new tool in the treatment of non-small-cell lung cancer (NSCLC) in non-surgical patients. There is growing evidence that RFA-mediated necrosis can modulate host immune responses. Here we analysed serum inflammatory factors as well as immunosuppressive cells in the peripheral blood to discover possible prognostic indicators. Peripheral blood and serum samples were collected before RFA and within 3 months after the treatment in a total of 12 patients. Inflammatory cytokines and growth factors were measured in serum by the Bio-Plex assay. Myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs ) were evaluated in the peripheral blood via flow cytometry. In patients developing local or lymphogenic tumour relapse (n=4), we found an early significant increase in the concentration of tumour necrosis factor (TNF)-α as well as chemokine (C-C motif) ligand (CCL)-2 and CCL-4 compared to patients without relapse (n=4) and healthy donors (n=5). These changes were associated with an elevated activity of circulating MDSC indicated by an increased nitric oxide (NO) production in these cells. Elevated serum levels of TNF-α, CCL-2 and CCL-4 associated with an increased NO production in circulating MDSCs might be an early indicator of the incomplete RFA and subsequently a potential tumour relapse in NSCLC.

Myeloid-derived suppressor cells and tumor escape from immune surveillance.

Tumor progression is known to be supported by chronic inflammatory conditions developed in the tumor microenvironment. It is characterized by the long-term secretion of various inflammatory soluble factors (including cytokines, chemokines, growth factors, reactive oxygen and nitrogen species, prostaglandins, etc.) and strong leukocyte infiltration. Among leukocytes infiltrating tumors, myeloid-derived suppressor cells (MDSCs) represent one of the most important players mediating immunosuppression and supporting tumor escape. These cells can strongly inhibit antitumor immune reactions mediated by T cells and NK cells. Moreover, MDSCs are generated, recruited to the tumor site, and activated not only under the influence of soluble inflammatory mediators but also due to extracellular vesicles (EVs) secreted by tumor cells. EVs play a key role in the formation of MDSCs via the conversion of normal myeloid cells and altering the normal myelopoiesis. In addition, EVs help create a suitable microenvironment for the metastatic process.