To confirm that FoxM1/RAD51–BRCA2 pathway activity is FoxO3a-dependent in irradiated fibroblasts, we next examined the effect of radiation on the protein expression of γH2AX, RAD51, BRCA2, and the viability of IPF fibroblasts co-overexpressing FoxO3a and FoxM1. Here, BRCA2 is linked to idiopathic pulmonary fibrosis.