Interestingly, low-dose splenic radiation may reduce CTLA-4 expression on the Treg cell surface to inhibit liver tumor development and researchers observed a significant decrease of the percentage of CD4+CD25+Treg/CD4+ cells in the blood and the expressions of Foxp3, IL-10, TGF-β, and CTLA-4 in spleen and liver tumors in this diethylnitrosamine-induced rat liver tumor model.349 Low-dose RT also sensitizes tumor cells to immune rejection by locally activated CAR T cells. This evidence concerns the gene CTLA4 and neoplasm.