NF1 and neoplasm: We are also grateful to R. Hiesinger, H. Kramer, D. van Meyel, R. Palmer and M. Therrien for additional fly stocks, to Spyros Artavanis-Tsakonas and Doug Dimlich for Exelixis deficiency stocks, and to Eline Beert and Eric Legius for NF1 tumor cell RNAs.