Larval brains were dissected, fixed, and stained similarly to previously described (Zhu et al. 2012 (link)). Primary antibodies: guinea pig anti-Ase (1:1000), rabbit anti-Dpn (1:500) rat anti-cd8 GFP (1:400 from invitrogen 13-0081-82), rat anti-tdtom (Kerafast EST203), chicken anti-GFP (1:400 from Aves laboratory GFP-1020) chicken anti-mcherry (1:400 from Novus biologics NBP2-25158). Cleaved Caspase staining (rabbit anticleaved DCP-1) (1:200; Asp216, Cell Signaling Technology 9578S). Secondary antibodies: Alexa Fluor 488 (Invitrogen A-11006), Alexa Fluor 555 (A-21428), or 633(A-21105) (Invitrogen) were used at 1:400 and DAPI staining at 1:1000. Before imaging, brains were mounted onto slides with vectashield and coverslipped. Imaging was preformed using either Leica SP5 or Leica SP8. Brain tumor images were acquired with 1-µm stacks. MARCM clones and type II lineages were acquired with 0.5-µm stacks. Imaris 5.5 software was used for volume measurement and cell counting.