CDX2 and gastric cancer: However, in a recent study, Rotkrua et al. indicated that miR-9 might be involved in gastric carcinogenesis through down-regulating CDX2, and knockdown of miR-9 decreased the in vitro proliferation of gastric cancer MKN-45 cells [19], while their findings need be further strengthened with miR-9 over-expression, target gene rescue, and in vivo studies.