CORRELATION OF SNAIL AND LYMPHOCYTE ACTIVATION GENE-3 WITH CLINICOPATHOLOGICAL PARAMETERS AND PROGNOSIS IN NON–SMALL CELL LUNG CANCER

Ling Su*, Hua Tang**, Hong Bao*, #

*Department of Respiratory Medicine, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai, PR China - **Department of Thoracic Surgery, Shanghai Changzheng Hospital, Shanghai, PR China

Objective: To investigate the correlation of the zinc finger protein SNAI1 (snail) and lymphocyte activation gene-3 (LAG-3) with clinicopathological parameters and prognosis in non–small cell lung cancer (NSCLC). 

Methods: A total of 108 cases of NSCLC and adjacent tissues were randomly selected from June 2017 to May 2018. The positive expression rates of snail and LAG-3 in NSCLC and adjacent tissues were detected by immunohistochemistry. The relationship between snail, LAG-3, and clinicopathological features was analyzed. The patients were followed up and the relationship between snail and LAG-3 and the survival time of NSCLC patients was analyzed. Cox proportional risk regression model was used to explore the independent risk factors affecting NSCLC patients. 

Results: Snail protein was mainly expressed in cytoplasm. The positive expression rate of snail protein in NSCLC tissues was 61.21%, which was significantly higher than that in adjacent tissues (5.01%, P<0.05). LAG-3 protein was mainly expressed in cytoplasm or cell membrane. The positive expression rate of LAG-3 protein in NSCLC tissues was 45.41%, which was significantly higher than that in adjacent tissues (5.11%, P<0.05). The positive expression of snail protein in NSCLC tissues was correlated with lymph node metastasis, TNM stage, nerve infiltration, and angioma thrombus (P<0.05), but not with age, sex, and degree of tissue differentiation (P>0.05). The positive expression of LAG-3 protein in NSCLC was correlated with TNM stage, lymph node metastasis, neural invasion, and angioma thrombus (P<0.05), but not with age, sex, smoking, pathological type, and differentiation (P>0.05). The 3-year survival rate of patients with snail protein–positive expression was 12/66 (18.48%), significantly shorter than that of patients with LAG-3 protein–negative expression, which was 24/42 (57.43%). The 3-year survival rate of patients with positive expression of LAG-3 protein was 8/50 (16%), significantly shorter than that of patients with negative expression of LAG-3 protein, which was 28/58 (48.27%). TNM stage, snail expression, and LAG-3 expression are independent risk factors affecting the prognosis of NSCLC patients. 

Conclusion: Both snail and LAG-3 are highly expressed. The positive expression of snail protein is related to lymph-node metastasis, TNM stage, neural invasion, and vascular thrombus. The positive expression of LAG-3 protein is related to TNM stage, lymph node metastasis, nerve infiltration, and vascular thrombus. Both of them are closely related to the occurrence and development of tumors, which may be a potentially significant biological target in NSCLC therapy.