Variable YAP1 expression in embryonal tumors. (A) A classical medulloblastoma shows no staining for YAP1. (B) A classical medulloblastoma shows high level YAP1 staining. (C) A nodular desmoplastic medulloblastoma shows high level staining in internodular areas but weak or negative staining in the nodule (*). High YAP1 expression is also shown in a medulloepithelioma (D), an atypical teratoid rhabdoid tumor (E), and a central primitive neuroectodermal tumor (F). Original magnifications: A, B, D-F, 100×; C, 64×.