Notably, we observed that RT had a direct effect on HO-1, resulting in increased HO-1 expression and cleavage in all 5 tumor cell lines (Figure 4A and Supplemental Figure 4A); and the induction of HO-1 expression by RT was dose dependent below 10 Gy (Supplemental Figure 4B). The gene discussed is HMOX1; the disease is neoplasm.