Analysis Of The Correlation Between Treg Cell Infilitration And SUV_max And Its Role In Prognosis Of Non-small Cell Lung Cancer

Objective:Foxp3+ positive regulatory T-cells(Tregs)are negative regulators in T cell subsets.Tregs can induce the immune escape and thus the prompted growth and metastasis of tumors by producing inhibitory cytokines(IL-6,IL-10,TNF-β)and expressing co-inhibitory molecules(CTLA-4、PD-1、LAG-3).The metabolism of cancer cells is distinct to that of normal tissue,and due to their active proliferation,malignant cells usually have greater glucose uptake than normal cells,according to which,through application of the radiolabeled tracer [18F] fluoro-D-glucose(FDG)for 18F-FDG positron emission tomography(PET)/computed tomography(CT),we could quantify tumor metabolic activity by the maximum standardized uptake value(SUVmax).It combines anatomy and metabolism activity,and is widely used in the diagnosis,staging,treatment and prognosis of lung cancer.The aim of this study is to investigate the correlation between Treg cell infiltration and SUVmax on PET-CT and its role in prognosis of non-small cell lung carcinoma(NSCLC),in order to find non-invasive methods to detect the infiltration of Treg cells in patients to evaluate the prognosis and guide clinical medication.Methods:One hundred and twenty two samples of NSCLC patients who underwent PET/CT imaging and were diagnosed in Cancer Institute and Hospital,Tianjin Medical University from March 2008 to October 2014 were enrolled.All the enrolled patients had undergone resection without preoperative chemotherapy or radiotherapy.Immunohistochemistry was used to detect the Tregs infiltration in carcinoma tissues.Survival outcomes were analyzed using the Kaplan-Meier method 、 Log-rank test method,and multivariate Cox proportional hazards model.Correlation between Treg cells infiltration and clinicopathological factors were analyzed using Pearson correlation analysis and Spearman rank correlation analysis.Results:1.Treg cells were divided into two groups at the level of cutoff value(75.3).Univariate analysis showed that Treg cell infiltration was risk factor of the prognosisof patients.2.The correlation between Treg cells infiltration and clinic pathological feature:The infiltration of Treg cells were positively correlated with tumor size,lymph node metastasis and tumor stage(r=0.289,0.186,0.340),and the difference was statistically significant(P=0.001,P=0.04,P<0.001).3.Patients were divided into two groups according to the level of SUVmax cutoff value(10.6),and patients of low SUVmax had longer median overall survival than patients of high SUVmax in univariate analysis(80 vs.52 months,P=0.012).4.There was a positive correlation between Treg cells and SUVmax(r=0.291,P=0.001).5.Multivariate Cox analysis demonstrated that tumor TNM stage(HR=7.537,95%CI: 1.191-2.855,P=0.006)was independent predictors for survival.ConclusionThere was a positive correlation between Treg cells and SUVmax,they were all the risk factors for survival.SUVmax may indicate Treg cells infiltration in the tumor microenvironment of NSCLC patients,and it may play an important role in predicting clinical prognosis and guiding treatment in patents with no-small lung cell cancer.