Perturbations to the Wnt signaling pathway have been implicated in a large proportion of human hepatocellular carcinomas (HCCs). Activating b-catenin mutations and loss of function mutations in Axin1 are thought to be functionally equivalent. We examined the Wnt pathway in HCC by comparing the expression of b-catenin target genes and the level of b-catenin-dependent transcriptional activation, in 45 HCC tumors and four cell lines. Among these samples, b-catenin and AXIN1 were mutated in 20 and seven cases, respectively. We found a significant correlation between activated b-catenin mutations and overexpression of mRNA for the target genes glutamine synthetase (GS), G-protein-coupled receptor (GPR)49 and glutamate transporter (GLT)-1 (P ¼ 0.0001), but not for the genes ornithine aminotransferase, LECT2, c-myc and cyclin D1. We also showed that GS is a good immunohistochemical marker of b-catenin activation in HCC. However, we observed no induction of GS, GPR49 or GLT-1 in the five inactivated Axin1 tumors. b-Catenin-dependent transcriptional activation in two Axin1-mutated HCC cell lines was much weaker than in b-catenin-mutated cell lines. Our results strongly suggest that in HCC, contrary to expectation, the loss of function of Axin1 is not equivalent to the gain of function of b-catenin. Our results also suggest that the tumor suppressor function of Axin1 in HCC may be related to another, non-Wnt pathway.

IMPORTANCE The benefit of adjuvant chemotherapy after resection of pancreatic cancer following neoadjuvant combination treatment with folinic acid, fluorouracil, irinotecan, and oxaliplatin (FOLFIRINOX) is unclear.OBJECTIVE To assess the association of adjuvant chemotherapy with overall survival (OS) in patients after pancreatic cancer resection and neoadjuvant FOLFIRINOX treatment.