Identification of portal vein tumor thrombus with an independent clonal origin in hepatocellular carcinoma via multi-omics data analysis

Malignant Portal Vein Thrombosis with No Obvious Liver Parenchymal Mass on Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography

The presence of portal vein thrombosis (PVTT) in hepatocellular carcinoma (HCC) is associated with adverse prognosis with dismal survival. Malignant portal vein thrombosis usually develops as a contiguous extension of the liver tumour into portal vein or its branches. Here we present an interesting FDG PET-CT image of a patient with chronic hepatitis B infection having isolated malignant portal vein thrombosis without any obvious liver mass.

Progress on the molecular mechanism of portal vein tumor thrombosis formation in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors, with poor prognosis and high mortality. Early-stage HCC has no obvious clinical symptoms, and most patients are already at an advanced stage when they are diagnosed. Portal vein tumor thrombus (PVTT) is the most common complication and a poor prognostic factor for HCC, which frequently leads to portal vein hypertension, ascites, gastrointestinal bleeding, and tumor metastasis. The formation of PVTT is related to the complex structure and hemodynamic changes of the portal vein and is closely related to changes at the cellular and molecular levels. The differentially-expressed genes (DEGs) between PVTT and primary tumor (PT) suggest that the two tissues may have different clonal origins. Epigenetic and proteomic analyses also suggest complex and diverse mechanisms for the formation of PVTT. In addition, the tumor microenvironment and energy metabolism pathways are interrelated in regulating the invasion and progression of PVTT. Aerobic glycolysis and the tumor immune microenvironment have been the focus of recent studies on PVTT. In this review, we summarize the mechanism of PVTT formation at the cellular and molecular levels to provide information to guide better prevention and treatment of PVTT in the clinic.

Elevated serum CA19-9 indicates severe liver inflammation and worse survival after curative resection in hepatitis B-related hepatocellular carcinoma

We explored the prognostic value of preoperative CA19-9 in α-fetoprotein (AFP)-positive and -negative HCC with hepatitis B virus (HBV) background (HBV-HCC), and explored the underlying mechanism. Recurrence-free survival (RFS) and overall survival (OS) were assessed in HBV-HCC patients who underwent curative resection (Cohort 1). Immunohistochemical staining of CA19-9 in HCC and liver parenchyma were quantified in another cohort of 216 patients with resected HCC (Cohort 2). Immunohistochemical staining of CA19-9 and serum CA19-9 level was also compared between patients with HCC and intrahepatic cholangiocarcinoma (ICC) (Cohort 3). In Cohort 1, CA19-9 ≥ 39 U/mL was an independent risk factor for RFS (HR = 1.507, 95% CI = 1.087-2.091, p = 0.014) and OS (HR = 1.646, 95% CI = 1.146-2.366, p = 0.007). CA19-9 ≥ 39 U/mL was also associated with significantly higher incidence of macrovascular invasion (MaVI) compared with CA19-9 < 39 U/mL (23.0% vs. 7.2%, p = 0.002), and elevated aminotransferase and aspartate aminotransferase to platelet ratio index (APRI), and lower albumin. Immunohistochemical staining of CA19-9 revealed that CA19-9 expression was found exclusively in the background liver but not in HCC tumor cells. In contrast, tumor tissue was the main source of CA19-9 in ICC patients. CA19-9 ≥ 39 U/mL was associated with worse OS and RFS in both AFP-positive and negative HCC patients. CA19-9 indicated more severe inflammation and cirrhosis in the liver of HCC patients.

circular RNA cia-MAF drives self-renewal and metastasis of liver tumor-initiating cells via transcription factor MAFF

Liver tumor-initiating cells (TICs) are involved in liver tumorigenesis, metastasis, drug resistance and relapse, but the regulatory mechanisms of liver TICs are largely unknown. Here, we have identified a functional circular RNA, termed circRNA activating MAFF (cia-MAF), that is robustly expressed in liver cancer and liver TICs. cia-MAF knockout primary cells and cia-maf knockout liver tumors harbor decreased ratios of TICs, and display impaired liver tumorigenesis, self-renewal and metastatic capacities. In contrast, cia-MAF overexpression drives liver TIC propagation, self-renewal and metastasis. Mechanistically, cia-MAF binds to the MAFF promoter, recruits the TIP60 complex to the MAFF promoter, and finally promotes MAFF expression. Loss of cia-MAF function attenuates the combination between the TIP60 complex and the MAFF promoter. MAFF is highly expressed in liver tumors and liver TICs, and its antisense oligo (ASO) has therapeutic potential in treating liver cancer without MAFA/MAFG gene copy number alterations (CNAs). This study reveal an additional layer for liver TIC regulation as well as circRNA function, and also provide an additional target for eliminating liver TICs, especially for liver tumor without MAFA/MAFG gene CNAs.

Identification of prognostic biomarkers associated with the occurrence of portal vein tumor thrombus in hepatocellular carcinoma

The occurrence of portal vein tumor thrombus (PVTT) is strongly correlated to the staging and poor prognosis of hepatocellular carcinoma (HCC) patients. However, the mechanisms of PVTT formation remain unclear. This study aimed to investigate differentially expressed genes (DEGs) between primary tumor (PT) and PVTT tissues and comprehensively explored the underlying mechanisms of PVTT formation. The DEGs between PT and paired PVTT tissues were analyzed using transcriptional data from the Gene Expression Omnibus (GEO) database. The expression, clinical relevance, prognostic significance, genetic alternations, DNA methylation, correlations with immune infiltration, co-expression correlations, and functional enrichment analysis of the DEGs were explored using multiple databases. As result, 12 DEGs were commonly down-expressed in PVTT compared with PT tissues among three datasets. The expression of DCN, CCL21, IGJ, CXCL14, FCN3, LAMA2, and NPY1R was progressively decreased from normal liver, PT, to PVTT tissues, whose up-expression associated with favorable survivals of HCC patients. The genetic alternations and DNA methylation of the DEGs frequently occurred, and several methylated CpG sites of the DEGs significantly correlated with outcomes of HCC patients. The immune infiltration in the tumor microenvironment of HCC was correlated with the expression level of the DEGs. Besides, the DEGs and their co-expressive genes participated in the biological processes of extracellular matrix (ECM) organization and focal adhesion. In summary, this study indicated the dysregulation of ECM and focal adhesion might contribute to the formation of PVTT. And the above seven genes might serve as potential biomarkers of PVTT occurrence and prognosis of HCC patients.