YAP1 and neoplasm: As a result, we found that loss-of-function mutations in a tumor-suppressor gene rab5[10], a small GTPase essential for generating early endosomes[11], in clones of cells overexpressing a pro-growth microRNA bantam (bantam/rab5-/- cells), a target of the Hippo pathway effector Yorkie (Yki), in the eye discs resulted in drastic tumor growth and malignant invasion to adjacent organ ventral nerve cord (VNC) (Figs 1c and S1e, quantified in S1f Fig).