CCND1 and glioblastoma: D’Onofrio et al (2003) examined the immunocontent of cyclin D1 and D2 and the activation of MAPK pathway in primary GBM cell cultures in serum-deprived conditions and in proliferative conditions (cells incubated with EGF for 8 h, for assessment of cyclin D1/D2, or for 10 min, for assessment of MAPK pathway) [68].