FAS and neoplasm: The sensitivity of T CD8+ T cells to apoptosis was linked to high levels of Fas expression in the majority of these cells present in the peripheral circulation, and both the frequency of Fas+CD8+ T cells and expression levels of Fas on these cells were significantly increased in patients with advanced disease, a large tumor burden, and those with the metastatic lymph node involvement (Hoffmann et al., 2002; Tsukishiro et al., 2003).