Combination therapy with anti‐T‐cell immunoglobulin and mucin‐domain containing molecule 3 and radiation improves antitumor efficacy in murine hepatocellular carcinoma

Background and Aim T‐cell immunoglobulin and mucin‐domain containing molecule 3 (TIM3) has emerged as a promising immune checkpoint inhibitor target; however, immune checkpoint inhibitor monotherapy does not benefit a substantial percentage of patients. Therefore, this study investigated the antitumor effect of anti‐TIM3 therapy combined with radiation in a murine hepatocellular carcinoma (HCC) model. Methods The effect of radiation on TIM3 expression was determined in murine and human HCC cells using western blotting, immunohistochemistry, and flow cytometry. Tumor growth and survival rate were measured to evaluate the antitumor effect of this combination therapy. Tumor immunological parameters were assessed using flow cytometry and histology. Results TIM3 was upregulated in tumor‐infiltrating CD8+ and CD4+ T cells in radiation‐treated HCa‐1‐implanted mice. Combination treatment significantly delayed tumor growth compared with monotherapy (P