pRb expression in human RMS. (A) Western blotting of human aRMS (Rh30,Rh41) and eRMS (Rh18, RD) cell lines. (B) Clinical RMS samples. alv, aRMS; emb, eRMS; ana, with anaplasia; pleo, pleomorphic RMS. (C) to (H) Immunohistochemistry of a human rhabdomyosarcoma tissue microarray using an anti-phospho pRb antibody that detects phosphorylation at Ser807/811. Staining was nuclear, cytoplasmic or both in any given cell, but the percentage of cells stained variably between 0 and 80%.