Cannabinoid Receptor 2 Tumor Tissue Gene Expression Positively Affects Lung Cancer Survival Following Radical Surgery.

Abstract Background: Non-small cell lung cancer (NSCLC) is a leading cause of cancer-related death with a 5-year survival rate of 21%. New treatment options are thus required, and the endogenous cannabinoid system is a potential new therapeutic target. We therefore analysed the expression of cannabinoid 1 and 2 receptor (CB1 and CB2) genes in NSCLC tissue and its influence on survival following radical surgery. Method: CB1 and CB2 gene expression in tumor tissue samples collected from 100 NSCLC patients was analysed using the quantitative real-time polymerase chain reaction. Since gene expression may not correlate with protein production, the presence of the CB2 protein was validated by immunohistochemistry. CB2 gene expression was correlated with disease stage, the presence of lymph node and distant metastases, tumor size, tumor grade, and survival. Result: Patients with tumors expressing CB2 gene had significantly longer overall survival (OS) (p<0.001), cancer-specific survival (CSS) (p=0.002), and disease-free survival (DFS) (p<0.001). They also had less advanced disease stage (p=0.047) and fewer lymph node metastases (p=0.011) at the time of surgery. A multivariate analysis showed that CB2 tumor tissue gene expression was a positive prognostic factor for OS (Hazard ratio (HR) = 0.402, p=0.013), CSS (HR=0.344, p=0.025), and DFS (HR=0.274, p=0.003). CB1 gene expression had no effect on survival. CB1 and CB2 gene expression was detected in 50% and 79.6% of the tumor tissue samples, respectively, and immunohistochemistry confirmed a correlation between CB2 gene expression and the presence of the CB2 protein in tumor tissues. Conclusion: In NSCLC patients undergoing radical surgery, CB2 gene expression in tumor tissue is associated with less advanced disease stage, fewer lymph node metastases, and longer survival (OS, CSS, DFS). Acknowledgement: This study was supported by Ministry of Health of the Czech Republic (NV18-03-00470), Ministry of Education, Youth and Sport of the Czech Republic (LM2018132), Palacky University Olomouc (LF 2020_007), Technological Agency of the Czech Republic (TN01000013), European Regional Development Fund (ENOCH CZ.02.1.01/0.0/0.0/16_019/0000868) and Cancer Research Czech Republic. Citation Format: Josef Srovnal, Monika Vidlarova, Emil Berta, Petr Prasil, Pavla Kourilova, Josef Chudacek, Marian Hajduch. Cannabinoid receptor 2 tumor tissue gene expression positively affects lung cancer survival following radical surgery [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 665.