TWIST1 and glioblastoma: Similarly, average tumor sizes in control mice were two- to fourfold higher than that in Twist1-deficient mice at days 22 to 25 in the GL261 model (Fig. 3F) and at days 17, 19, and 21 in the RCAS model (Fig. 3G), collectively suggesting an important role of endothelial Twist1 in GBM growth.