FAS and neoplasm: Tumour necrosis factor-related apoptosis-inducing ligand has been shown to exert enhanced apoptotic activity on tumour cells, while non-tumour cells have been reported to be resistant to TRAIL-induced death in many systems (Walczak et al, 1999), whereas FASL kills only sensitive FAS-bearing cells by inducing apoptosis (O'Connell et al, 1999; Grosch et al, 2001).