To evaluate whether abnormal expression of CLDN6 enhanced tumorigenicity of gastric cancer in vivo, gastric cancer cells transfected with sh-CLDN6 and empty vector constructs, were injected subcutaneously and into the spleen of nude mice, respectively, to generate xenograft subcutaneous tumor model and liver metastasis model (Fig. 4a, e). Here, CLDN6 is linked to neoplasm.