Characterization of a New Human Embryonal Rhabdomyosarcoma Cell Line, RMS‐GR

A human tumor cell line designated RMS‐GR was established from an embryonal rhabdomyosarcoma. The monolayer cells were polygonal, round or spindle‐shaped. The RMS‐GR cell line became stable with a doubling time of 42 h. Tumorigenicity of the cells was confirmed by hetero‐transplantion into nude mice. Electron microscopic images showed typical cytoplasmic inclusion of aggregated intermediate filaments and myofibril‐like thin filaments. The expression of desmin, vimentin, actin and human myoglobin was recognized by cytofluorometric analyses, and a large fraction of CK‐MM and small fractions of CK‐BB and MCK‐1 isoenzymes were found. Chromosomal analysis showed that the modal chromosome number was consistently near triploid with structural abnormalities mostly involving chromosomes 1, 3 and 8, and additional unidentified markers. No alteration of chromosome 2 was observed. The RMS‐GR cell line may provide a system to identify genes which are involved in the pathogenic mechanism of rhabdomyosarcomas, and to investigate the modulation of myogenic differentiation.