Increased circulating GrMyeloid-derived suppressor cells correlated with tumor burden and survival in locally advanced cervical cancer patient

Background: Myeloid-derived suppressor cells (MDSCs) may lead to immune evasion and disease progression in some cancers, but their roles remain to be investigated in cervical cancer. This study aimed to characterize the specific subsets of MDSCs that might be potential indicators for disease progression in cervical cancer patients. Methods: Different subsets of MDSCs were characterized using flow cytometry in blood samples from healthy subjects and cervical cancer patients. T-cell proliferation assay was performed in vitro. Tumor infiltrating CD8+ and FOXP3+ cells were also evaluated by immunostaining on the tumor tissues from patients with early and locally advanced cervical cancer. We further analyzed the relevance of circulating MDSCs to clinicopathological characteristics, patient survival as well as tumor infiltrating lymphocytes. Results: The frequency of circulating GrMDSCs increased correlated with FIGO stage while the percentage of MoMDSCs only elevated in patients with advanced cervical cancers. For patients with early and locally advanced cervical cancer, the frequency of circulating GrMDSCs but not MoMDSCs correlated with clinicopathologic parameters including metastatic lymph nodes, deep stromal invasion and tumor recurrence. The levels of circulating GrMDSCs also negatively correlated with the densities of CD8+ cells in tumor tissues. In vitro assay showed that Gr-MDSCs suppressed the proliferation of autologous T cells. Conclusion: Our study demonstrates that the increased frequency of circulating GrMDSCs is associated with tumor burden and recurrence in early and locally advanced cervical cancer patients, that the GrMDSCs may be potential biomarkers for disease progression cervical cancers.