Backgroud Transforming growth factor-β (TGF-β) can inhibit the growth of most epithelial and endothelial cells. The growth regulative role of TGF-β on soft tissue sarcoma was seldom reported. Here we examined TGF-β1 effects on the growth of human rhabdomyosarcoma cell RD and searched the relative molecular mechanism. Methods The viability of RD was examined by [ 3H]-thymidine incorporation and [3-(4,5-dimethylthiazol-z-yl)-2,5-diphenyltetraz olium bromide] (MTT) assay. RD cell cycle was analysed by flow cytometry. The protein and mRNA of cell cycle regulative factors in RD were detected by Western blot and reverse transcription-polymerase chain reation (RT-PCR), respectively. The kinase activity of cdk2 or cdk4 was examined by immunoprecipitation and kinase assay. Immunofluorescent staining was used to detect the location of cell cycle regulative factors in RD by laser scanning confocal microscope.Results TGF-β1 inhibits RD proliferation by G1-arrest in cell cycle progression. TGF-β1 can prominently up-regulate P27 of RD, then augment P27 to bind cyclinE-cdk2 complexes, which effectively suppress cdk2 kinase activity. P21 increased and c-myc decreased in RD due to TGF-β1. Both P15 and cdk4 have not been involved in the growth inhibitory event. TGF-β1 treatment induced P27 to congregate around nucleus. P21 pervaded from nucleus to both nucleus and cytoplasm by TGF-β1 treatment.Conclusion TGF-β1 inhibits the proliferation of human rhabdomyosarcoma cell line RD and induces RD G1-arrest. This course is accomplished by TGF-β1 up-regulating P27 to suppress cdk2 kinase activity. The induction of P21 and down-regulation of C-myc might participate in the growth-arrest event. The growth regulative role of TGF-β on soft tissue sarcoma was seldom reported. Backgroud Transforming growth factor-β (TGF-β) can inhibit the growth of most epithelial and endothelial cells. The growth regulatory role of the growth of human rhabdomyosarcoma cell RD and searched the relative molecular mechanism. Methods The viability of RD was was examined by [3H] -thymidine incorporation and [3- (4,5-dimethylthiazol-z- yl) -2,5-diphenyltetrazolium bromide] The protein and mRNA of cell cycle regulative factors in RD were detected by Western blot and reverse transcription-polymerase chain reation (RT-PCR), respectively. The kinase activity of cdk2 or cdk4 was examined by immunoprecipitation and kinase assay. Immunofluorescent staining was used to detect the location of cell cycle regulative factors in RD by laser scanning confocal microscope. Results TGF-β1 inhibits RD proliferation by G1-arrest in cell cycle progression. TGF-β1 can prominently up-regulate P27 of RD, then augment P27 to bind cyclin E-cdk2 complexes, which effectively suppress cdk2 kinase activity. P21 increased and c-myc decreased in RD due to TGF- β1. Both P15 and cdk4 have not was involved in the growth inhibitory event. TGF-β1 treatment induced P27 to congregate around nucleus. P21 pervaded from nucleus to both nucleus and cytoplasm by TGF-β1 treatment. Conflux TGF-β1 inhibits the proliferation of human rhabdomyosarcoma cell line RD and induces RD G1-arrest. This course is accomplished by TGF-β1 up-regulating P27 to suppress cdk2 kinase activity. The induction of P21 and down-regulation of C-myc might participate in the growth-arrest event.