The Expression Pattern of Immune Checkpoint Genes Related to Immune Regulatory Cells (GITR and LAG-3) in Colorectal Cancer Patients.

[BACKGROUND] Immune cells that predominantly contribute to the homeostasis and regulation of the immune system are regulatory T (T reg) cells. The specific markers of these cells, which are considered as immune control points, play a role in the function and regulation of the immune activity of these cells, and their expression can be related to clinicopathological features of colorectal cancer (CRC). The aim of the present study was to evaluate the expression changes of immune checkpoint genes of T reg cells (glucocorticoid-induced tumor necrosis factor receptor [GITR] and lymphocyte-activation gene 3 [LAG-3]) in patients with CRC.

[MATERIALS AND METHODS] 30 peripheral blood mononuclear cell (PBMC) samples from patients with CRC and 30 samples from healthy individuals were studied. A quantitative polymerase chain reaction (qPCR) was completed for analyzing the relative expression of immune checkpoint genes of T reg cells (GITR and LAG-3). The relationship with clinicopathological features and diagnostic values of the genes was examined. REST and SPSS software were used for statistical analyses.

[RESULTS] The results showed that the expression of LAG-3 (but not GITR) gene in the population of PBMCs of patients with CRC has a significant decrease in expression compared to healthy individuals. Further analyses showed that these expression changes were not related to the clinicopathological characteristics of the CRC patients.

[CONCLUSION] The expression pattern of immune checkpoint genes of T reg cells in CRC patients may have a clinical value. Hence, investigation of a larger population of patients can be useful in order to evaluate their diagnostic power in differentiating between healthy and tumor patients.