Hepatocellular adenoma subtype classification using molecular markers and immunohistochemistry.
Hepatocellular adenomas (HCA) with activated beta-catenin present a high risk of malignant transformation. To permit robust routine diagnosis to allow for HCA subtype classification, we searched new useful markers. We analyzed the expression of candidate genes by quantitative reverse transcription polymerase chain reaction QRT-PCR followed by immunohistochemistry to validate their specificity and sensitivity according to hepatocyte nuclear factor 1 alpha (HNF1alpha) and beta-catenin mutations as well as inflammatory phenotype. Quantitative RT-PCR showed that FABP1 (liver fatty acid binding protein) and UGT2B7 were downregulated in HNF1alpha-inactivated HCA (P <or= 0.0002); GLUL (glutamine synthetase) and GPR49 overexpression were associated with beta-catenin-activating mutations (P <or= 0.0005), and SAA2 (serum amyloid A2) and CRP (C-reactive protein) were upregulated in inflammatory HCA (P = 0.0001). Immunohistochemistry validation confirmed that the absence of liver-fatty acid binding protein (L-FABP) expression rightly indicated HNF1alpha mutation (100% sensitivity and specificity), the combination of glutamine synthetase overexpression and nuclear beta-catenin staining were excellent predictors of beta-catenin-activating mutation (85% sensitivity, 100% specificity), and SAA hepatocytic staining was ideal to classify inflammatory HCA (91% sensitivity and specificity). Finally, a series of 93 HCA was unambiguously classified using our 4 validated immunohistochemical markers. Importantly, new associations were revealed for inflammatory HCA defined by SAA staining with frequent hemorrhages (P = 0.003), telangiectatic phenotype (P < 0.001), high body mass index, and alcohol intake (P <or= 0.04). Previously described associations were confirmed and in particular the significant association between beta-catenin-activated HCA and hepatocellular carcinomas (HCC) at diagnosis or during follow-up (P < 10(-5)).


CONCLUSIONS
We refined HCA classification and its phenotypic correlations, providing a routine test to classify hepatocellular adenomas using simple and robust immunohistochemistry.
Department of Pathology, CHU Bordeaux, France.
Paulette
P
Bioulac-Sage
Sandra
S
Rebouissou
Cristel
C
Thomas
Jean-Frédéric
JF
Blanc
Jean
J
Saric
Antonio
A
Sa Cunha
Anne
A
Rullier
Gaëlle
G
Cubel
Gabrielle
G
Couchy
Sandrine
S
Imbeaud
Charles
C
Balabaud
Jessica
J
Zucman-Rossi
D018248:Adenoma, Liver Cell / Q000145:classification* / Q000473:pathology*; D000328:Adult; D014408:Biomarkers, Tumor / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D050556:Fatty Acid-Binding Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D005260:Female; D014453:Glucuronosyltransferase / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D005974:Glutamate-Ammonia Ligase / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D051538:Hepatocyte Nuclear Factor 1-alpha / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008113:Liver Neoplasms / Q000145:classification* / Q000473:pathology*; D008297:Male; D051176:beta Catenin / Q000378:metabolism
D014408:Biomarkers, Tumor; C493319:FABP1 protein, human; D050556:Fatty Acid-Binding Proteins; C496487:HNF1A protein, human; D051538:Hepatocyte Nuclear Factor 1-alpha; D051176:beta Catenin; C491474:UGT2B7 protein, human; D014453:Glucuronosyltransferase; D005974:Glutamate-Ammonia Ligase