KLRK1 and gastric cancer: In addition, we acknowledge that other NKG2D ligands, such as ULBP2‐6, MICA, and MICB, and other markers of EMT, such as E‐cadherin, Twist, and Snail, might also be involved in the interaction of NK cells with tumor cells.76, 77 To further confirm the role of EMT, as well as the relationship between ULBP1 expression and EMT in the immune evasion of CTCs, functional studies introducing NK cells into a culture system of gastric cancer cell lines, and studies expanding the range of molecules detected on gastric CTCs, are now warranted.