The Wnt/beta-catenin signalling pathway is activated in many human hepatocellular carcinomas (HCC). Identification of beta-catenin mutation relies mostly on sequence analysis and/or immunohistochemistry. beta-catenin mutation may also be detected by analysing the expression of its target genes. The GLUL gene encoding glutamine synthetase (GS), for example, appears to be a pertinent marker. The aim of this study was to correlate GS immunostaining and beta-catenin mutations with clinicopathological features in HCC. We found that GS immunostaining had a sensitivity of 90% for the detection of beta-catenin mutations, with 98% specificity, whereas beta-catenin immunostaining had a sensitivity of 63% with 98% specificity. We used the sensitive GS marker to characterize 190 HCC cases. Sixty-eight (36%) cases displayed Wnt/beta-catenin activation. In addition to their well-differentiated pattern, these tumours exhibited significant features such as a homogeneous microtrabeculo-acinar pattern, low-grade cellular atypia, and cholestasis. As these tumours exhibited cholestasis, we hypothesized that beta-catenin acts on specific bile synthesis and/or transport pathways. In conclusion, we propose that GS immunostaining and a cholestatic pattern are relevant criteria for the identification of HCC with beta-catenin mutations.

Purpose: Activation of the Wnt/b-catenin signaling pathway is frequent in adrenocortical carcinoma (ACC) and might be associated with a more aggressive phenotype. The objective of this study was to assess the prognostic value of b-catenin immunohistochemistry and CTNNB1 (b-catenin gene)/APC (adenomatous polyposis coli gene) mutations in patients with resected primary ACC.Experimental design: In 79 patients with resected primary ACC from a French cohort (Cochin-COMETE), b-catenin expression was assessed on tumor specimens by immunohistochemistry. For patients with available DNA (n ¼ 49), CTNNB1, and APC hotspot (mutation cluster region), were sequenced. Association between these results and the clinicopathologic characteristics of the ACC and overall and disease-free survival were studied. Results were confirmed on a tissue microarray from an independent multicentric cohort of 92 ACC from Germany (German-ENSAT cohort).Results: In the Cochin-COMETE cohort, the presence of a b-catenin nuclear staining was significantly associated with a higher ENSAT tumor stage (i.e., stages III and IV), higher Weiss score, more frequent necrosis, mitoses, and CTNNB1/APC mutations. b-Catenin nuclear staining and the presence of CTNNB1/ APC mutations were both associated with decreased overall and disease-free survival, and were independent predictive factors of survival in multivariate analysis. The same results were observed in the German-ENSAT cohort.Conclusions: Wnt/b-catenin activation, confirmed by the presence of b-catenin nuclear staining, is an independent prognostic factor of overall and disease-free survival in patients with resected primary ACC.