Expression And Clinical Significance Of CD33~+HLA-DR~-Myeloid-derived Suppressor Cells In The Peripheral Blood Of Renal Carcinoma

Background:Renal cell carcinoma (RCC) is one of the most common cancer threaten to humans health, which is steadily increasing at a rate of about2.5%per year across population groups. RCC accounts for3%of all adult malignancies and is the most lethal of the urologic cancers. More than40%of patients with RCC will die from their cancer compared to the approximately20%mortality rates associated with prostate and bladder cancers. Approximately20～30%of patients present with metastatic disease, and20～40%undergoing nephrectomy for clinically localized RCC will develop metastases. The accidental diagnosis of RCC has increased due to the extensive use of ultra sonography, leading to an earlier diagnosis and probably better prognosis. The rate of occurence of RCC increased continuously over the last50years, and the annual mortality raised to36.5%. Significant advances in the diagnosis, staging, and treatment of patients with RCC during the last two decades have resulted in improved survival of a select group of patients and an overall change in the natural history of the disease. Recent advances in the understanding of the pathogenesis, behavior, and molecular biology of RCC have paved the way for developments that may enhance early diagnosis, better predict tumor prognosis, and improve survival for RCC patients, despite advances in biological and immune-based therapies, response rates for patients with metastatic RCC remain at about15-25%.numerous genetic, cytogenetic, immune histochemical analysis and/or proteomic approaches, biomarkers that allow clinicians to detect RCC at an early stage and deliver prognostic information about the patients overall disease outcome, allowing specific and effective intervention in RCC therapy, are still missing.RCC is rarely detected in earlier stages; its diagnosis is delayed because of the lack of visible symptoms.In contrast to other urological cancers, RCCs are associated with high potential of metastases, Metastatic RCC (mRCC) presents a particular therapeutic challenge for clinicians because of the resistance of kidney cancer to chemotherapy or radiotherapy and the limited response to immunotherapy. Recently, the multitargeted tyrosine kinase inhibitors sunitinib and sorafenib have been assessed for patients with metastatic mRCC. Satisfactory results have been achieved, and one of the mechanism of anti-tumor is associated with MDSCs. It can decrease the level of MDSCs in patient blood.Recent studies describe a heterogeneous population of cells of the myeloid lineage, termed myeloid derived suppressor cells (MDSC). Their frequency is increased in the peripheral blood, lymph nodes, and bone marrow, as well as at the tumor sites in animal tumor models and in human cancers. In mice, MDSCs are classified as either monocytic by expression of CDllb+Ly6G-Ly6Chigh(Gr-llow) or granulocytic by expression of CD11b+Ly6G+Ly6Clow(Gr-1high). Human MDSCs are similarly classified into CD14+monocytic MDSCs or CD15+granulocytic MDSCs. Human MDSCs also express common myeloid markers CDl1b and CD33but lack HLADR and other surface markers for lymphoid cells (CD3/CD19/CD56). CDllb+CD14-CD15+HLADR-cells with a granulocytic morphology were reported in patients with non-small cell lung carcinoma.CD14+CD11b+HLADR-/low MDSCs exhibiting monocytic morphology were reported in melanoma, hepatocellular carcinoma, and ovarian carcinoma, suggesting that different human tumors induce different subtypes of MDSCs.Since their discovery these cells have been called among others,"natural suppressors","immature myeloid cells"(IMC) or "myeloid suppressor cells"(MSC). Although these names reflected the biology of the cells, this allowed confusion with mesenchymal stem cells (also MSC). Therefore, a uniform name was suggested as MDSC reflecting their origin and function.MDSC are now recognized as a key immunosuppressive cell type in the development and progression of malignancy the prevalence of these cells and their immunosuppressive capacity has been reported including in multiple diverent malignancies including head and neck, prostate, and breast. Accumulation of MDSC in the peripheral circulation has been related to extent of disease, and correlates with stage. MDSC have primarily been implicated in promoting tumor growth by suppressing antitumor immunity. There is also compelling evidence MDSC are also involved in angiogenesis and metastatic spread. Moreover, MDSCs also play a role in other pathological conditions, such as inflammation, acute and chronic infection, trauma, and some autoimmune diseases.MDSCs were statistically significantly elevated in pancreatic, esophageal and gastric cancer compared with controls and associated with clinic stages. Increasing MDSC percentage was associated with increased risk of death, and in a multivariate analysis, MDSC level was an independent prognostic factor for survival. A unit increase in MDSC percentage was associated with a22%increased risk of death (hazard ratio1.22,95%confidence interval1.06-1.41.Objectiove: Although several studies have analyzed the phenotype and function of MDSC in murine systems, much less is known regarding the relevance and immunosuppressive action of MDSC in cancer patients. the aim of this study was To investigate the expression of CD33+HLA-DR-myeloid-derived suppressor cells (MDSCs) in peripheral blood of renal carcinoma patients and its correlation with clinicopathologic features of renal cancer. This will help clinicians to refine their follow-up and to individualize treatment strategies. As markers for RCC, if validated, have the potential to detect tumor progression at an earlier stage and to diagnosis and treatment early and To assist in prognosis and to protect patients from psychological pressure and unnecessary therapies through exposure to radiological treatment.Methods and materials:Forty-four renal cell carcinoma patients were selected from Department of Urology, Zhujiang Hospital, Southern Medical University (June.2011to Oct.2012), confirmed by Computed Tomography and pathology, without preoperative chemotherapy radiotherahy and without immunotherapy, without other system tumors and trauma, without Infectious Diseases and autoimmune diseases(AID). Age from23to78years, median age was51years,27cases of males and17females.18healthy volunteers were used as control. Age from25to72years, median age was49years. According to the American Joint Committee on Cancer (AJCC) Cancer Staging Manual, sixth edition (2002),20cases of stages Ⅰ+Ⅱ,11cases of stage Ⅲ,13cases of stage Ⅳ. According to the pathological diagnosis of postoperative specimens,20cases of renal clear cell carcinoma,8cases of renal papillary adenocarcinoma,9case of chromophobe renal carcinoma. Blood collected from patients with stages Ⅰ-Ⅳ renal cell carcinoma patients and Two milliliters of venous blood was collected in K2EDTA-lavender top tubes in preoperative and postoperative peripheral blood thirty days. Placed nitrogen tank immediately for postoperative specimens, then transfer it into the refrigerator of laboratory. The Protocol Review Committee of the Southern Medical University approved this study. Written consent was obtained from subjects. Peripheral blood was drawn from patients with RCC and healthy donors in K2EDTA-lavender top tubes and processed within2hours. Blood was diluted with an equal volume of plain RPMI and then layered over Ficoll. The solution was centrifuged at2000×g for20min by density centrifugation. Peripheral blood mononuclear cells (PBMCs) were isolated from the interface and washed in RPMI. Cell surface staining was performed on PBMC isolated by Ficoll-density centrifugation using monoclonal antibodies for CD33, and HLA-DRCD33according to the manufacturer’s instructions. Flow Cytometry analysis was used to detect the CD33+HLA-DR-MDSCs expression in peripheral blood, and its correlation with cliniccpathologic features of renal cancer was analyzed.Results:(1) The MDSCs with the phenotype of CD33+HLA-DR-exist in patients’ peripheral blood, as well as in the tumor primary location, and the positive rate of CD33+HLA-DR-MDSCs expression was significantly popular in the peripheral blood mononuclear cell of renal carcinoma than express in peripheral blood mononuclear cell of healthy controls [(1.91±0.66)%vs (0.62±0.22)%, P<0.001].(2) The CD33+HLA-DR-MDSCs expression in renal carcinoma patients was positively correlated with tumor stage[stage Ⅰ+Ⅱ vs stage Ⅲ(1.46±0.44)%vs (2.04±0.35)%, P<0.01; stage Ⅲ vs stageIV(2.04±0.35)%vs (2.50±0.64)%, P<0.05], correlated with the Lymph node and distant metastasis[(2.48±0.39)%vs (1.59±0.46)%, P<0.001]. pathological type indicates CCRCC is significant increase correlated with PRCC and CRCC. PRCC no significant difference with CRCC.(3) The CD33+HLA-DR-MDSCs expression in renal carcinoma patients not correlated with the age, gender. No significant correlation was identified between the proportion of CD33+HLA-DR-MDSCs and other clinicopathological features, including, tumor diameter, histological grade.Conclusions:(1) CD33+HLA-DR-MDSCs expression in peripheral blood is associated with tumor stage and the lymph node and distant metastasis in renal carcinoma and may play an important role in prediction in prognosis and tumor immunology of renal carcinoma.(2) MDSCs in renal cell carcinoma suggest the clinical significance of circulating and tumor infiltrating MDSCs and may provide new insights into the renal cell carcinoma immunotherapy targeting MDSCs, that pharmacologic blockade of MDSCs should be considered in future clinical trials.