FASLG and neoplasm: Specifically, NK cells play an important role in tumor immune surveillance (Ljunggren and Karre, 1985; Terme et al., 2008; Vivier et al., 2008), as they control progression of MHC-I-deficient tumors using perforin/granzyme- and FasL-mediated cytotoxicity (Van den Broek et al., 1995; Screpanti et al., 2001; Pardo et al., 2002).