To investigate the role of ICAM-1 in the systemic antitumor effect of RT, we used a highly immunogenic MC38 tumor model 26 by subcutaneously implanting tumor cells into the right hind flank (primary; irradiated tumor) and left hind flank (distant; non-irradiated tumor) of wild-type (WT) or ICAM-1 knockout (ICAM-1 KO) C57BL/6 mice (Figure 1A). The gene discussed is ICAM1; the disease is neoplasm.