The expression of BiP (GRP78), spliced XBP1 (sXBP1, nuclear XBP1), and IRE1α, were significantly associated with Rhabdomyosarcoma (RMS) in the four main RMS subtypes: alveolar (ARMS), embryonal (ERMS), pleomorphic (PRMS) and sclerosing/spindle cell (SRMS) RMS; (n = 192) compared to normal skeletal muscle tissues (n = 16). The gene discussed is XBP1; the disease is rhabdomyosarcoma.