FN1 and neoplasm: Interestingly, NK cells interacting with tumor cells exhibited completely different behaviors depending on microwell coating proteins [Figure 5A and Movies S1, S2 in supplementary information (SI)]: NK cells in BSA-coated microwells formed stable cell-cell contacts with round tumor cells (Figure 5A top panel and Movie S1), whereas NK cells in FN-coated microwells continuously migrated on flat tumor cells (Figure 5A bottom panel and Movies S2).