[32]. However, since some Eomes+ CD49a+ ILC1s were S1PR5FM+ and S1PR5 is only expressed by mature NK cells, but not by CD27+ CD11b- immature NK cells, the question of whether cytotoxic ILC1ls can also be derived from NK cells remains open for debate [32]. This question is especially relevant since, as mentioned in Section 4, McFarland et al. showed in their study that tumor-specific clusters generated from the PyMT tumor model expressed Irf8, a marker of conventional NK cells, together with Gzmc[12]. This evidence concerns the gene S1PR5 and neoplasm.