Fibroblasts of neurofibromatosis type 1 showed no abnormality in p21ras-mediated response to serum in culture.

In order to disclose the possible disturbance in regulation of p21ras function in neurofibromatosis type 1, we investigated the recovery from the quiescent to cycling states of the cell cycle in the skin fibroblasts of the patients. When cells cultured in serum-dependent medium are deprived of the serum, these go into the quiescent state (G0). On being returned to the serum-containing medium, the cells re-enter S phase. The skin fibroblasts from neurofibromatosis type 1 patients, and normal subjects were brought into the quiescent state by serum-starvation, and after the re-addition of the serum, the recovery to cycling states were analysed by flow cytometry. There was no apparent difference between these fibroblasts in the progression from G0 to S phase.