GFAP and glioma: To further verify the correlation between the level of noise in the cyclin D1 protein concentration and the differentiation rate of glioma cells, we will utilize time-lapse microscopy and a customized cell tracking system to monitor the degradation of cyclin D1 and the levels of the differentiation marker GFAP in thousands of individual cells under exposure to cholera toxin at a series of effective doses (5 to 10 ng/ml) [2].