Fractionation irradiation induces anti-tumor abscopal effect in BalB/C and SCID mice. The primary and secondary tumors of group Sham and group RT were marked as Sham-Pt, Sham-St, RT-Pt and RT-St, respectively. The growths of both primary and secondary tumors were delayed in radiotherapy (RT) group of BalB/C mice (A), SCID(4T1) (B), SCID(MDA-MB-231) mice (C), but not in NOD-SCID mice (D). (E) Total numbers of nodules on the surface of lung were decreased by RT in BalB/C and SCID mice at 7 dpr, 18dpr (BalB/C) and 12 dpr (SCID), respectively. (F) Representative photographs of mice lung with metastasis nodules of 4T1 cells. Black arrows point to lung nodules. Data are from 10 mice/group (n=10) and are presented as the mean ± SD. * p<0.05 and *** p<0.001 between indicated groups. n.s. not significant. Scale bar, 5mm.