IL2 and breast cancer: A large body of preclinical data has been published on the use of RT with immunostimulatory molecules such as interleukin-2 (IL-2), FMS-like tyrosine kinase 3 ligand (Flt3-L), and Toll-like receptor (TLR) ligands to generate the abscopal effect in mouse models of renal cell carcinoma, breast cancer, and colon cancer.