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p16[SUPINK4A] (p16) tumour suppressor induces growth arrest by inhibiting function of cyclin-dependent kinase (CDK)4 and CDK6. Homozygous p16 gene deletion is frequent in primary rhabdomyosarcoma (RMS) cells as well as derived cell lines. To confirm the significance ofp16 gene deletion in tumour biology of RMS, a temperature-sensitivep16 mutant (E119G) gene was retrovirally transfected into the human RMS cell line RD, which has homozygous gene deletion ofp16 gene. Decrease from 40°C (restrictive) to 34°C (permissive) culture temperature reduced CDK6-associated kinase activity and induced G1 growth arrest. Moreover, RD-p16 cells cultured under permissive condition demonstrated differentiated morphology coupled with expressions of myogenin and myosin light chain. These suggest that deletion ofp16 gene may not only facilitate growth but also inhibit the myogenic differentiation of RD RMS cells. [ABSTRACT FROM AUTHOR]