When ALDH1A2 and ALDH2 were overexpressed in Beas-2b immortalised lung epithelial cells that did not contain an ALDEFLUOR+ cell subpopulation, the resulting Beas-2BALDH1A2 or Beas-2BALDH2 cells were mixed with K562 leukaemia cells or H1299 lung cancer cells at percentages of 20–25%, and the mixed cell populations were analysed using the ALDEFLUOR system.17 The gene discussed is ALDH1A2; the disease is lung carcinoma.