PTGS2 and gastric cancer: Interestingly, simultaneous detection of COX2 and β-catenin immunoreactivity in these GC tumors is observed in 8 out of 12 identical individuals (Figure S6 and Table S2), arguing in favor of a positive relationship between COX2 expression and the intracellular levels of the β-catenin protein, and thus the activity of the canonical Wnt signaling pathway in the transcriptional regulation of the COX2 gene.