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 heterotransplantion 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.