GDH cells retain their strategic position even in advanced GBM-xenografts (Figure S6 N–U) and, interestingly, shed Cdc42+-particles in the lumen of dilated vessels in 7-day grafts, which are also found in sinusoidal vessels in 1-month-tumours (Figure S6 X, Y). The gene discussed is CDC42; the disease is glioblastoma.