FSTL1 and neoplasm: Furthermore, the FASL-FAS pair was inferred between three NK subclusters and FSTL1+ tumor cells, and between three NK subclusters and NEAT1+ tumor cells, while GZMAhigh NK cells presented the highest interacting value (Fig. 5H), indicating that GZMAhigh NK cells may induce apoptosis in tumor cells through death receptor systems [54].