Immunochemical differentiation of rhabdomyosarcomas.

Abstract

When six rhabdomyosarcomas were stained with antisera by the fluorescein label technic, three (classified as embryonal and usually difficult to diagnose as rhabdomyosarcoma) appeared to contain myosin, since they reacted with antimyosin antibody, whereas the remaining three, which were easier to classify as typical rhabdomyosarcoma histologically, appeared to contain no myosin. Anticonnective tissue serum gave different results in that the embryonal cells did not contain connective tissue antigenic components, whereas the typical rhabdomyosarcoma cells did (except for one of the adult rhabdomyosarcomas where only partial staining was seen). The question arises whether the adult muscle tumors are of muscle origin or of stromal origin. If these tumors come from skeletal muscle cells, they must have lost the ability to synthesize myosin in amounts detectable by the fluorescent antibody technic.