A, Histology (Hematoxylin and eosin, H&E) of rhabdomyosarcoma tumors for Myf6ICNm/WT Pax3P3Fm/P3Fm Trp53F2-10/F2-10 Rosa26Lusapm/WT mice harboring wildtype Hr alleles (Control, left) or homozygous SKH1 mutation (SKH1, right). B, Tumors were positive for myogenin (arrows) in both cohorts. C to D, Tumors in both cohorts also harbored infiltrating CD56+ NK cells and CD163+ macrophages, respectively (arrows). All panels represent 400×.