TNF-α and CD95L play a crucial role in the activation induced cell death (AICD) of mature T cells (Dhein et al, 1995; Zheng et al, 1995) whereas TRAIL has been shown to induce apoptosis mainly in tumour cells (Wiley et al, 1995; Walczak et al, 1999) but also in normal human hepatocytes, astrocytes and keratinocytes (Jo et al, 2000). This evidence concerns the gene TNF and neoplasm.