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Keywords:

  • β-catenin;
  • hepatocellular carcinoma;
  • glutamine synthetase;
  • cholestasis;
  • ABCG2/BCRP;
  • claudin2;
  • bile acids

Abstract

The Wnt/β-catenin signalling pathway is activated in many human hepatocellular carcinomas (HCC). Identification of β-catenin mutation relies mostly on sequence analysis and/or immunohistochemistry. β-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 β-catenin mutations with clinicopathological features in HCC. We found that GS immunostaining had a sensitivity of 90% for the detection of β-catenin mutations, with 98% specificity, whereas β-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/β-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 β-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 β-catenin mutations. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.