These results strongly suggest that WNT3 might play a key role in some cases of human breast, rectal, lung, and gastric cancer through activation of the WNT - beta-catenin - TCF signaling pathway, similar to mouse Wnt-3.
To determine the role of beta-catenin defects in stomach cancer, we investigated beta-catenin exon 3 mutations and altered protein expression in 77 primary gastric carcinomas and 11 cell lines.
These results strongly suggest that up-regulation of WNT10A induced by TNFalpha and H. pylori might play key roles in human gastric cancer through activation of WNT--beta-catenin--TCF signaling pathway.
A beta-catenin gene mutation was identified only in one intestinal-type gastric cancer exhibiting a massive overexpression of beta-catenin mRNA in the tumour.
To clarify the clinical significance of TSG expression in gastric carcinoma, the expression of various TSG candidates (p53, E-cadherin, FHIT, smad4, rb, VHL, PTEN, MGMT, p16, and KAI1), as well as other proteins (bcl-2, MUC1, MUC2, MUC5AC, MUC6, CEA, CD44, beta-catenin, C-erbB2, and cyclin B2), was evaluated immunohistochemically in 329 consecutive gastric carcinomas using the tissue array method.
Examples of genes involved in pathogenesis of GC include p53, adenomatous polyposis coli (APC), beta-catenin, E-cadherin, transforming growth factor (TGF)-betaRII, and hMLH1.
These data suggest that inactivating mutations of the Siah-1 may contribute to the development of gastric cancer through beta-catenin stabilization and apoptosis block.
Altered distribution of beta-catenin has been found in many human malignancies including gastric cancer, but its reason(s) and biological implications have not yet been fully clarified.
These biological factors are often derived from the genetic process, which is thought to represent a crucial step to gastric cancer (DNA copy number changes, microsatellite instability, thymidilate synthase, E-cadherin, beta-catenin, mucin antigen, p53, c-erb B-2, COX-2, matrix metalloproteinases, VEGFR and EGFR).
In this study, we investigated whether gene amplification is a possible mechanism of beta-catenin activation in gastric cancer by determining its presence in 49 patients with gastric cancer and two gastric-derived cell lines (KATO III and ST2957).
Beta-catenin gene (CTNNB1) mutations have been described predominantly in intestinal-type gastric cancers and CTNNB1 gene amplification and overexpression have recently been described in a mixed-type gastric cancer.
Calcyclin-binding protein/Siah-1-interacting protein (CacyBP/SIP), a target protein of S100, has been identified as a component of a novel ubiquitinylation complex leading to beta-catenin degradation, which was found to be related to the malignant phenotypes of gastric cancer.