Fig. 6: Immunohistochemical staining and FOXO1-FISH of rhabdomyosarcoma tumor sections.

Tissue sections from the four depicted tumors were stained with Hematoxylin and Eosin (upper left picture), with the mAb PFM.2 (upper right picture), an antibody directed against AP2β (lower right picture) and by FISH using a FOXO1 break-apart probe (bap) (lower left picture). The depicted tumors are positive for PAX3-FOXO1 (upper left case), PAX7-FOXO1 (upper right case), or negative for known fusion proteins in poorly differentiated ERMS (lower left case) and translocation negative ARMS (lower right case).