Thus, knockdown of Atg8a or Atg9 cooperates with RasV12 to result in neoplastic tumours and blocks metamorphosis at the larval–pupal stage, a characteristic observed previously with other Ras-cooperating mutations, for example, in the apicobasal polarity genes, scrib, dlg, lgl and baz,12, 13, 35 or upon overexpression of actin cytoskeletal genes, RhoGEF2, pbl (RhoGEF), Rac1 and bsk (Jun kinase).36, 37. This evidence concerns the gene RAC1 and neoplasm.