RAD51 and neoplasm: The functional REcombination CAPacity (RECAP) test determines the capacity of proliferating tumor cells to accumulate RAD51 protein at ionizing-radiation-induced DNA double strand breaks (DSBs) by co-immunofluorescence staining (co-IF) for RAD51 and geminin (GMN), a marker for the G2/S phase, in which HR can take place [31,40,41].