PTEN and neoplasm: Similarly to BEAS-Akt1-E17K cells, BEAS cells expressing mutant PIK3CA or silenced for PTEN showed a pronounced increase in the number and size of LCSs generated, expressed consistently higher mRNA levels of Oct-4, Nanog and Sox2, and were able to efficiently sustain tumor growth in vivo as LCSs at low number (Supplemental Figure S2A–S2E).