FAS and Carcinoma, Lewis Lung: It has been reported that Lewis lung carcinoma cells were constitutively resistant to Fas-mediated apoptosis, but the overexpression of Fas on these cells allows Fas-mediated apoptosis after cross-linking with agonist anti-Fas antibody [30], which suggests that there is a qualitative difference in the activated signaling cells receive, which determines their fate after Fas signaling ligation.