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Background and Aims: Hepatobiliary phase (HBP) Gd‐EOB‐DTPA‐enhanced magnetic resonance imaging (MRI) has increased the accuracy in differentiating focal nodular hyperplasia (FNH) and hepatocellular adenoma (HCA). However, the ability of this technique to distinguish HCA subtypes remains controversial. The aim of this study was to investigate the expression of hepatocyte transporters (OATPB1/B3, MRP2, MRP3) in HCA subtypes, hence to understand their MRI signal intensity on HBP Gd‐EOB‐DTPA‐enhanced MRI. Methods: By means of immunohistochemistry (IHC), we scored the expression of OATPB1/B3, MRP2 and MRP3, in resected specimens of FNH (n = 40), subtyped HCA (n = 58) and HCA with focal malignant transformation (HCA‐HCC, n = 4). Results were validated on a supplementary set of FNH (n = 6), subtyped HCA (n = 17) and HCA‐HCC (n = 1) with Gd‐EOB‐DTPA MR images. Results: All FNH showed a preserved expression of hepatocytes transporters. Beta‐catenin‐activated HCA (at highest risk of malignant transformation) and HCA‐HCC were characterized by preserved/increased OATPB1/B3 expression (predictor of hyperintensity on HBP), as opposed to other HCA subtypes (P < 0.01) that mostly showed OATPB1/B3 absence (predictor of hypointensity on HBP). HCA‐HCC showed an additional MRP3 overexpressed profile (P < 0.01). On HBP Gd‐EOB‐DTPA‐enhanced MRI, FNH and HCA signal intensity reflected the profile predicted by their specific OATPB1/B3 tissue expression. The hyperintense vs hypointense HBP signal criterion was able to distinguish all higher risk HCA and HCA‐HCC (100% accuracy). Conclusions: OATPB1/B3 and MRP3 IHC and signal intensity on HBP Gd‐EOB‐DTPA‐enhanced MRI can help to stratify HCA according to their risk of malignant transformation. [ABSTRACT FROM AUTHOR]

Background & Aims Although potentially very useful in optimizing patient selection and follow-up, the individual response to transarterial chemoembolization (TACE) in hepatocellular carcinoma (HCC) is generally unpredictable. The aim of this study was to identify tissue predictors of tumour resistance to TACE for use in clinical practice on pretreatment biopsies. Methods We investigated the association of residual tumour in post-TACE-resected HCC with pathological and immunophenotypical features, mainly related to hypoxia and angiogenesis. Comparison of tumour phenotype between post-TACE HCC and both paired pre-TACE biopsies and control TACE-untreated HCC was performed. Cases showing >50% residual tumour (RT) were defined as TACE-resistant. Results A consecutive series of 108 HCC from 41 patients was studied. Overall, 45/108 (44%) HCC were classified as TACE-resistant. Among these, 32 (71%) and 40 (89%) showed diffuse CD34 vascular staining and negative VEGF staining respectively (p<0.05). The association of these two parameters in a weighted score (TRIP) was able to predict TACE resistance with 81% accuracy, 89% sensitivity and 59% specificity. The effectiveness of TRIP was validated in an independent series of 28 HCC biopsies from patients subsequently treated with TACE and for whom radiological follow-up was available. Conclusions This study demonstrates the potential value of pretreatment tumour biopsy as predictors of TACE resistance in HCC. [ABSTRACT FROM AUTHOR]