The tumour-promoting effect of cathepsins is in contrast to the observation that cathepsins such as Cath-B can mediate proapoptotic signals triggered by TNF (Foghsgaard et al, 2001; Guicciardi et al, 2001; Mathiasen et al, 2001), bile salts (Roberts et al, 1999), sphingosine (Kagedal et al, 2001), activation of the B-cell receptor (Katz et al, 2001), and L-2,5-dihydrophenylalanine (Kiso et al, 2001). Here, TNF is linked to neoplasm.