SMAD4 and central nervous system cancer: From the results of real-time PCR, we further clarified that, at the mRNA level, Smad4, N-cadherin, and VPA have an impact on the EMT process in both glioma cell lines after treatment with different VPA doses (control, 1.2, 2.4, and 5 mmol/1) and for different times (0, 12, 24, and 48 hours).