Differential diagnosis of small hepatocellular nodules in cirrhosis: surrogate histological criteria of TERT promoter mutations

AIMS

The differential diagnosis of small hepatocellular nodules in cirrhosis between dysplastic nodules and hepatocellular carcinoma (HCC) remains challenging on biopsy. As TERT promoter (pTERT) mutations may indicate the nodules already engaged in the malignant process, the aim of this study was to identify histological criteria associated with pTERT mutations by detecting these mutations by ddPCR in small formalin-fixed paraffin-embedded (FFPE) hepatocellular nodules arising in cirrhosis.

METHODS AND RESULTS

We built a bicentric cohort data set of 339 hepatocellular nodules < 2 cm from cirrhotic samples, divided into a test cohort of 299 resected samples and a validation cohort of 40 biopsies. Pathological review, based on the evaluation of 14 histological criteria, classified all nodules. pTERT mutations were identified by ddPCR in FFPE samples. Among the 339 nodules, ddPCR revealed pTERT mutations in 105 cases (31%), including 90 and 15 cases in the test and validation cohorts, respectively. On multivariate analysis, three histological criteria were associated with pTERT mutations in the test cohort: increased cell density (P = 0.003), stromal invasion (P = 0.036) and plate-thickening anomalies (P < 0.001). With the combination of at least two of these major criteria, the AUC for predicting pTERT mutations was 0.84 in the test cohort (sensitivity: 86%, specificity: 83%) and 0.81 in the validation cohort (sensitivity: 87%, specificity: 76%).

CONCLUSIONS

We identified three histological criteria as surrogate markers of pTERT mutations that may be used in routine biopsy to more clearly classify small hepatocellular nodules arising in cirrhosis.

Hepatocellular Carcinomas: Towards a pathomolecular approach

Molecular analysis of primary liver malignancies has provided a refinement of the pathological diagnosis of this entity and the identification of an increasing number of tumor subtypes of hepatocellular proliferation, either malignant (hepatocellular carcinomas) or benign (hepatocellular adenomas). Besides the diagnosis, a combined pathomolecular approach can also provide further insights into patient prognosis, and help select patients who can benefit from targeted therapies. Hepatocellular carcinomas define a heterogeneous group of malignant hepatocellular proliferation at various levels: macroscopic, histological and molecular. While most carcinomas occur in patients with chronic liver diseases and advanced fibrosis in the background liver, some arise from the malignant transformation of a pre-existing hepatocellular adenoma. TERT promoter mutations are the most frequent genomic alterations observed in the process of malignancy, and they occur early in the process of liver carcinogenesis. Overall, a more active biopsy strategy should be considered a key step in the management of patients with HCC.

Diagnostic Value of Glypican3, Heat Shock Protein 70 and Glutamine Synthetase in Hepatocellular Carcinoma Arising in Cirrhotic and Non-Cirrhotic Livers

BACKGROUND AND OBJECTIVES

Histopathological distinction of various nodular lesions in liver with sufficient sensitivity and specificity is a challenge even in an expert set up. The panel of immunohistochemical markers composed of glutamine synthetase (GS), Glypican3 (GPC3) and heat shock protein 70 (HSP70) was recommended by the International Consensus Group for Hepatocellular Neoplasia group for the differentiation of high grade dysplastic nodule and early hepatocellular carcinoma (HCC). The panel has been extensively validated in the western population. This study aims to test this panel on Indian population on resected, explanted and autopsy cirrhotic and non-cirrhotic liver specimens of HCC.

METHODOLOGY

This study was conducted on 39 such liver specimens (12 cirrhotic, 12 pre-cirrhotic and 11 non-cirrhotic, non-fibrotic livers), including 35 cases of HCC over a period of 12 years. Immunohistochemistry was performed with antibodies against GS, GPC3 and HSP70 on the sections containing both malignant and dysplastic nodules.

RESULTS

The diagnostic yield depended upon the nature of background liver pathology and was found to be high for only those HCCs arising in cirrhotic background, when positivity of any two markers was taken to be in favor of HCC (sensitivity-58.33%; specificity-100%). GS had a sensitivity and Negative predictive value of 100% for HCCs arising in cirrhotic livers.

CONCLUSIONS

Strong positivity for GS is a highly sensitive marker for HCC in a cirrhotic background regardless of the differentiation of the tumor in Indian population. This may be due to preferential activation of Wnt pathway in Indian patients with cirrhosis. The sensitivity of the panel was too low for detecting HCCs arising in non-cirrhotic livers, even in the pre-cirrhotic chronically inflamed livers, even though the specificity was high. GPC3 and HSP70 appear to be useful as individual markers for HCCs arising in non-cirrhotic livers.

Nonlinear tumor evolution from dysplastic nodules to hepatocellular carcinoma

Dysplastic nodules are premalignant neoplastic nodules found in explanted livers with cirrhosis. Genetic signatures of premalignant dysplastic nodules (DNs) with concurrent hepatocellular carcinoma (HCC) may provide an insight in the molecular evolution of hepatocellular carcinogenesis. We analyzed four patients with multifocal nodular lesions and cirrhotic background by whole-exome sequencing (WES). The genomic profiles of somatic single nucleotide variations (SNV) and copy number variations (CNV) in DNs were compared to those of HCCs. The number and variant allele frequency of somatic SNVs of DNs and HCCs in each patient was identical along the progression of pathological grade. The somatic SNVs in DNs showed little conservation in HCC. Additionally, CNVs showed no conservation. Phylogenetic analysis based on SNVs and copy number profiles indicated a nonlinear segregation pattern, implying independent development of DNs and HCC in each patient. Thus, somatic mutations in DNs may be developed separately from other malignant nodules in the same liver, suggesting a nonlinear model for hepatocarcinogenesis from DNs to HCC.

SUOX is a promising diagnostic and prognostic biomarker for hepatocellular carcinoma

BACKGROUND & AIMS

To investigate diagnostic and prognostic values of sulfite oxidase (SUOX) in patients with hepatocellular carcinoma (HCC) who underwent curative resection.

METHODS

We investigated immunohistochemically the expression dynamics of SUOX, aldo-ketoreductase family 1 member B10 (AKR1B10) and CD34 at different stages of HCC. The differential diagnostic performance of three markers or their combinations in high-grade dysplastic nodules (HGDNs) and well-differentiated small HCC (WD-sHCC) were investigated by logistic regression models and validated in an independent testing set. Overall survival (OS) and time to recurrence (TTR) were evaluated in 300 patients with HCC as the testing cohort, and validated in 198 patients with HCC.

RESULTS

SUOX was decreased and AKR1B10 and CD34 were increased with the stepwise progression of hepatocarcinogenesis. For differential diagnosis of WD-sHCC from HGDNs, the sensitivity and specificity of the SUOX+AKR1B10+CD34 combination for WD-sHCC detection were 93.8% and 95.2%, respectively, and overall accuracy was much higher than any of the three individual markers and two marker combinations. In addition, SUOX, but not AKR1B10 and CD34, was an independent prognostic factor for OS and TTR, and showed better correlation with OS and TTR if combined with serum α-fetoprotein (AFP) for both the testing and validation cohorts.

CONCLUSIONS

SUOX+AKR1B10+CD34 combination could make a substantial contribution to hepatic immunopathological diagnosis to distinguish WD-sHCC from HGDNs. Meanwhile, SUOX combined with serum AFP may predict postoperative outcome and tumor recurrence risk.