EGFR and neoplasm: Furthermore, ectopic activation of Src, EGFR, PI3K or Yki in simple columnar imaginal discs is sufficient to induce overproliferation of cells, whereas loss of PI3K or Yki strongly impairs imaginal disc tumour formation (Doggett et al., 2011; Enomoto and Igaki, 2013; Fernandez et al., 2014; Herranz et al., 2012, 2014; Strassburger et al., 2012; Willecke et al., 2011).