Fas downregulation is recognised as one of the mechanisms for evading the Fas–FasL system in other types of tumours, and a similar loss of Fas was shown to be a negative prognostic factor in acute lymphoblast leukaemia (Suminoe et al, 2004), lung cancer (Koomagi and Volm, 1999) and pancreatic cancer (Bernstorff et al, 2002). This evidence concerns the gene FAS and lung cancer.