In recent years, blood and tumor ILC-1s have been defined in the literature based on transcript expression of CD3D, CD3G, CD3E, CCL5, GMK, GZMM, GZMA, BCL11B, PRDM1, IKZF3, EOMES, and TBET (41), along with protein expression consisting of IL-7Rpos, c-KITneg, and CRTH2neg subsets (42). This evidence concerns the gene TBX21 and neoplasm.