BMP-4 reduces the amount of VACV needed to achieve growth inhibition in GBM CSCs and has no role in VACV oncolytic activity in glioma serum-grown cell lines. A) representative growth inhibition curves of GBM CSC line 040622 upon infection with the pair of VACVs, GLV-1h189 and GLV-1h285. The EC50 value for each virus is indicated by a black arrow intercepting the X-axis and the difference between the EC50 values is shown by the broad double headed arrow. B) EC50 values for GLV-1h189 and GLV-1h285 upon infection of 9 GBM CSC lines. The fold difference between the EC50 values of GLV-1h189 and GLV-1h285 viruses are in the column on the far right. C) EC50 values to indicate growth inhibition kinetics by GLV-1h189 and GLV-1h285 in two serum-grown glioma cell lines, U373 and U251 adapted to grow under stem cell conditions.