Correlation Of Gene And Immune Microenvironment With Lymph Node Metastasis In T1 Lung Adenocarcinoma

Objective: To study the correlation between gene and immune microenvironment characteristics and lymph node metastasis of T1 lung adenocarcinoma,and to explore the risk factors of lymph node metastasis of T1 lung adenocarcinoma.Further analyze the relationship between each other and establish a risk prediction model to provide translational research evidence for lymph node dissection and perioperative treatment of T1 lung adenocarcinoma.Materials and methods:(1)Patients with stage T1 lung adenocarcinoma who underwent lobotomy and systematic lymph node dissection in the department of thoracic surgery,second xiangya hospital,central south university from March 2016 to October 2020 were enrolled,and clinicopathological data were collected.(2)Whole exon sequencing was performed on postoperative tissue samples of patients to analyze the relationship between gene mutation spectrum and TMB and lymph node metastasis of stage T1 lung adenocarcinoma.(3)LASSO regression was used to screen gene mutations associated with lymph node metastasis in stage T1 lung adenocarcinoma.Tumor mutation score(TMS)was established according to the gene mutation status and coefficient,and the relationship between TMS and lymph node metastasis was analyzed.(4)Immunohistochemistry was used to detect PD-L1,CD3+TILs,CD8+TILs,CD68+TAMs and CD163+TAMs,and to calculate positive tumor proportion score(TPS)of PD-L1.Combined with combined positive score(CPS),the number of immune cells in central tumor(CT)and invasive margin(IM),the effect of immune microenvironment on lymph node metastasis of T1 lung adenocarcinoma was analyzed.(5)The relationship between lymph node metastasis,genotyping and immune typing was further analyzed by integrating gene and immune indexes.Results:(1)A total of 212 patients with stage T1 lung adenocarcinoma were included in this study,including 104 patients with lymph node metastasis and 108 patients without lymph node metastasis,male(p=0.017),poorly differentiated(p < 0.001),smoking history(p <0.001),and larger tumor(p < 0.001)were more likely to have lymph node metastasis.There was no significant correlation between age and tumor location and lymph node metastasis of T1 lung adenocarcinoma.(2)A total of 174 patients underwent genetic testing,including 87 patients with lymph node metastasis and 87 patients without lymph node metastasis.In the lymph node metastasis group,high frequency mutations were TTN,MUC17,SYNE1,MUC16,OBSCN,etc.The high frequency mutation of the non-metastatic group were EGFR,MUC16,TP53,HNRNPH1,etc.High TMB was a risk factor for lymph node metastasis of stage T1 lung adenocarcinoma(p < 0.001).(3)31 genes were found to be significantly correlated with metastasis risk by LASSO regression,namely DPCR1,OBSCN,PRKDC,TTN,MDN1,HECTD4,IVL,KIR2DS4,KRTAP10-8,SLC9B1,RAMP2,HNRNPH1,FLG2,etc.High TMS was associated with lymph node metastasis of stage T1 lung adenocarcinoma(p < 0.001).(4)Higher levels of TAMs and lower levels of TILs were found in patients with metastasis compared with those without lymph node metastasis(p < 0.05).(5)In patients with lymph node metastasis,the mutation frequency of TTN and FLG2 is higher,and the immune typing tends to be mixed;in patients without lymph node metastasis,the mutation frequency of TTN and FLG2 is lower,and the immune typing tends to be inflammatory.Conclusions:(1)DPCR1,OBSCN,PRKDC and other gene mutations may drive lymph node metastasis of T1 lung adenocarcinoma;(2)Tumor-infiltrating lymphocytes are negatively correlated with lymph node metastasis of T1 lung adenocarcinoma,and tumor-associated macrophages are positively correlated with lymph node metastasis of T1 lung adenocarcinoma;(3)Tumor mutation score correlates with immune microenvironment characteristics and has a good predictive value for lymph node metastasis in T1 lung adenocarcinoma.