FANCD2 and Fanconi anemia: Based on the functional understanding of the pathway, we developed an immunofluorescence-based method, FancD2/DAPI/Ki67 (Fanconi Anemia Triple Stain Immunofluorescence - FATSI), which permits the observation of FancD2 foci formation (or lack thereof) in the nucleus of proliferating cells in paraffin embedded tumor tissues (Fig. 1) [19].