Osada and Takahashi raise the intriguing notion that the ASH1 transcription factor might function as a lineage survival oncogene in pulmonary neuroendocrine cells (PNEC). Indeed, ASH1 seems to have a crucial role in the development of PNECs, has persistent expression in tumours from the PNEC lineage (lung tumours with neuroendocrine features) and might also be required for the survival of such tumours. Therefore, ASH1 fulfills four of the five criteria we proposed for lineage survival oncogenes in our recent review. As such, we would agree that ASH1 is a 'predicted' lineage survival oncogene. The demonstration that ASH1 is targeted by genetic alterations in PNEC tumours (or subsets therein) would provide a formal confirmation of its lineage-survival oncogenic function in vivo.