Data from our current study indicated that Wnt3A, FZD6, and CTNNB1 were up-regulated, while GSK-3β was down-regulated in MKN45/R and NCI N87/R cells when compared to their parental cells, suggesting the acquirement of trastuzumab resistance through activation of canonical Wnt/β-catenin pathway in gastric cancer. This evidence concerns the gene WNT3A and gastric cancer.