THE LEVEL OF IMMUNE CHECKPOINT CO-INHIBITORS IN TUMOR TISSUE IN PATIENTS WITH COLON TUMOR

Introduction. A high level of checkpoint co-inhibitors in the tumor microenvironment plays an important role in inhibiting the local immune response, which contributes to the growth and progression of cancer. The aim of the study. We aimed to determine immune checkpoint co-inhibitors level (CTLA-4, TIM-3, LAG-3, PD-1) and their ligands (B7-2, Galectin-9, PD-L1) in tumor tissue in patients with benign tumor of the colon and cancer. Methods: the study enrolled 94 patients divided into 3 groups: 44 patients with colorectal cancer, 25 with a benign colon tumor, 25 – a control group (patients who underwent plastic surgery of a colostomy formed earlier due to a colon injury). The level of immune checkpoint co-inhibitors and their ligands was studied in tumor tissue by flow cytofluometry on a CytoFlex LX analyzer (Beckman Coulter, USA) using the LEGENDplex ™ HU multiplex analysis kit (Immune Checkpoint, USA) Results: we found that in patients with colon cancer the level of immune checkpoint co-inhibitors (TIM-3, CTLA-4, LAG-3) in the homogenate supernatant of the tumor tissue was higher than in the control group. The level of TIM-3 protein increased by 43.6 times (p 0.001), CTLA-4 – by 2.3 times (p=0.007), LAG-3 – by 5.1 times (p 0.001). Patients with colorectal cancer also showed the elevation of the concentration of TIM-3 protein by 11.4 times (p <0.001), LAG-3 by 1.8 times (p=0.008), CTLA-4 protein by 1.5 times (p=0.02) compared to patients with benign colon tumor. In patients with colorectal cancer, the level of the TIM-3 ligand (Galectin-9) exceeded the indicator of the control group by 56.7 times (p <0.001), and the CTLA-4 ligand (B7-2) – by 1.7 times (p=0.004). In addition, the concentration of Galectin-9 in patients with CRC was 3.4 times higher (p<0.001), the B7-2 ligand was 1.5 times higher (p=0.04). compared to patients with benign colon tumor. Conclusion: an increase in the level of CTLA-4, TIM-3, LAG-3 and their ligands – B7-2 and Galectin-9 in tumor tissue indicates the involvement of these molecules in the cancer genesis of colorectal cancer.