The fact that the difference in Fas membrane expression does not correlate with the Fas expression in total cell lysates may be due to a different distribution of Fas, cytoplasmic and on the cell membrane, as was described in prostate carcinoma cell lines and neuroblastoma cell lines (Fulda et al, 1997; Usla et al, 1997; Bennett et al, 1998; Sodeman et al, 2000). Here, FAS is linked to prostate carcinoma.