NKX6-3 and neoplasm: Recently, Yoon et al. 2015, showed that NKX6.3, considered a possible tumor suppressor for GC, is a transcriptional factor for GKN1. They showed that NKX6.3 is strongly down-regulated in GC cells; however, its over-expression in AGS and MKN1 GC cells induced the re-expression of GKN1 protein [41].