Liver stem/progenitor cells in the canals of Hering: cellular origin of hepatocellular carcinoma with bile duct tumor thrombi? Stem Cell Rev Rep. 2010;6:579-584. [PMID: 20809255 DOI: 10.1007/s12015-010-9188-4]

Micro-hepatocellular carcinoma with bile duct tumor thrombus mimicking intrahepatic intraductal papillary neoplasm of the bile duct: a case report

BACKGROUND

Microhepatocellular carcinoma with a gross bile duct tumor thrombus is extremely rare, making the correct preoperative diagnosis difficult.

CASE PRESENTATION

A 78-year-old man was referred to our department for close examination of a liver tumor that was incidentally detected using ultrasonography. Blood tests revealed normal levels of tumor markers. Abdominal ultrasonography showed a 2-cm-sized hyperechoic mass with indistinct borders and hypoechoic margins at the origin of the right hepatic duct. Dynamic computed tomography showed a tumor with arterial phase predominance, a heterogeneous contrast effect, and prolonged enhancement. Cystic structures were observed in the tumors. In addition, localized dilatation of the caudate lobe bile duct was observed near the tumor. Cholangiography showed that the common bile duct, right and left hepatic ducts, and secondary branches did not have dilatation or stenosis. Biopsies of the bile duct revealed no malignancy. Under suspicion of intrahepatic intraductal papillary neoplasm of the bile duct, right hemi-hepatectomy was performed. The extrahepatic bile duct was preserved, because no tumor was found at the margin of the right hepatic duct during intraoperative frozen diagnosis. Macroscopically, the lesion was an 18 × 15 mm tumor occupying a dilated intrahepatic bile duct near the right hepatic duct, with a soft, fine papillary tumor. Based on morphology and immunostaining, tumor matched with moderately differentiated hepatocellular carcinoma. In addition, a 2 mm-sized hepatocellular carcinoma was observed in the liver parenchyma near the bile duct, where the tumor was located.

CONCLUSIONS

Based on these findings, the patient was diagnosed with small hepatocellular carcinoma with a gross bile duct tumor thrombus. The cystic part seen on the preoperative images was considered as a gap between the bile duct and the tumor thrombus. The patient recovered well with no signs of recurrence 20 months after surgery.

To be or not to be: The double-edged sword roles of liver progenitor cells

Given the liver's remarkable and unique regenerative capacity, researchers have long focused on liver progenitor cells (LPCs) and liver cancer stem cells (LCSCs). LPCs can differentiate into both hepatocytes and cholangiocytes. However, the mechanism underlying cell conversion and its distinct contribution to liver homeostasis and tumorigenesis remain unclear. In this review, we discuss the complicated conversions involving LPCs and LCSCs. As the critical intermediate state in malignant transformation, LPCs play double-edged sword roles. LPCs are not only involved in hepatic wound-healing responses by supplementing liver cells and bile duct cells in the damaged liver but may transform into LCSCs under dysregulation of key signaling pathways, resulting in refractory malignant liver tumors. Because LPC lineages are temporally and spatially dynamic, we discuss crucial LPC subgroups and summarize regulatory factors correlating with the trajectories of LPCs and LCSCs in the liver tumor microenvironment. This review elaborates on the double-edged sword roles of LPCs to help understand the liver's regenerative potential and tumor heterogeneity. Understanding the sources and transformations of LPCs is essential in determining how to exploit their regenerative capacity in the future.

Liver Cancer Cell of Origin, Molecular Class, and Effects on Patient Prognosis

Primary liver cancer is the second leading cause of cancer-related death worldwide and therefore a major public health challenge. We review hypotheses of the cell of origin of liver tumorigenesis and clarify the classes of liver cancer based on molecular features and how they affect patient prognosis. Primary liver cancer comprises hepatocellular carcinoma (HCC), intrahepatic cholangiocarcinoma (iCCA), and other rare tumors, notably fibrolamellar carcinoma and hepatoblastoma. The molecular and clinical features of HCC versus iCCA are distinct, but these conditions have overlapping risk factors and pathways of oncogenesis. A better understanding of the cell types originating liver cancer can aid in exploring molecular mechanisms of carcinogenesis and therapeutic options. Molecular studies have identified adult hepatocytes as the cell of origin. These cells have been proposed to transform directly into HCC cells (via a sequence of genetic alterations), to dedifferentiate into hepatocyte precursor cells (which then become HCC cells that express progenitor cell markers), or to transdifferentiate into biliary-like cells (which give rise to iCCA). Alternatively, progenitor cells also give rise to HCCs and iCCAs with markers of progenitor cells. Advances in genome profiling and next-generation sequencing have led to the classification of HCCs based on molecular features and assigned them to categories such as proliferation-progenitor, proliferation-transforming growth factor β, and Wnt-catenin β1. iCCAs have been assigned to categories of proliferation and inflammation. Overall, proliferation subclasses are associated with a more aggressive phenotype and poor outcome of patients, although more specific signatures have refined our prognostic abilities. Analyses of genetic alterations have identified those that might be targeted therapeutically, such as fusions in the FGFR2 gene and mutations in genes encoding isocitrate dehydrogenases (in approximately 60% of iCCAs) or amplifications at 11q13 and 6p21 (in approximately 15% of HCCs). Further studies of these alterations are needed before they can be used as biomarkers in clinical decision making.

Cancer stem cells in hepatocellular carcinoma--an immunohistochemical study with histopathological association

Background & objectives:

Cancer stem cells (CSCs) may be responsible for tumour recurrence and resistance to chemotherapy in hepatocellular carcinoma (HCC). This study was carried out to evaluate the association between histological parameters and liver CSCs (LCSC) in HCC, and to compare distribution of liver CSCs in HCC associated with and without hepatitis B virus (HBV) infection.

Methods:

Seventy nine tumours (49 surgical resections from 46 patients, and 30 from autopsy) were reviewed. Immunohistochemical staining for the LCSC marker EpCAM (epithelial cell adhesion molecule), liver progenitor cell (LPC) markers CK19 (cytokeratin 19) and neural cell adhesion molecule (NCAM) were performed and were associated with histological features of tumour behaviour.

Results:

Thirty three tumours (41.8%) showed positive staining for EpCAM. CK19 and NCAM expression were seen in 26 (32.9%) and four (5.1%) tumours, respectively. The expression of EpCAM and CK19 was significantly associated with each other (P<0.001). EpCAM expression was significantly associated with clinical and histological features indicating aggressive tumour behaviour, including younger age of onset, higher serum alpha foetoprotein (AFP) levels, tumour cell dedifferentiation, increased mitotic activity, and vascular invasiveness. There was no significant difference in expression of EpCAM, CK19 and NCAM between HBV positive and negative HCC.

Interpretation & conclusions:

The LCSC marker EpCAM was expressed in less than half of HCC, was independent of HBV aetiology, and was strongly associated with clinical and histological features of aggressive tumour behaviour. Positive staining for CK19 suggests a possible LPC origin of the EpCAM positive HCCs.

Clinicopathological characteristics and liver stem cell marker expression in hepatocellular carcinoma involving bile duct tumor thrombi

The aim of this study was to analyze the clinicopathological characteristics and expression of liver stem cell markers of hepatocellular carcinoma (HCC) involving bile duct tumor thrombi (BDTT). A total of 35 patients with HCC and BDTT in a consecutive series of HCC patients who underwent surgical treatment were studied retrospectively and compared with 916 patients without BDTT from the same series. Clinicopathological characteristics, overall survival (OS), and tumor expression of liver stem cell markers CD133, CD90, EpCAM, CK19, VEGF, and C-kit were compared between the two patient groups. Analysis was performed for the entire patient groups as well as for 35 pairs of patients with or without BDTT matched by propensity score. HCC patients with BDTT tended to have smaller tumors than those without BDTT, as well as a higher probability of having poorly differentiated tumor, Child-Pugh class B, liver cirrhosis, and microvascular invasion. Tumor tissue in patients with BDTT showed significantly higher expression rates of all liver stem cell markers examined. OS was significantly lower for patients with BDTT at 1 year (69 vs 84 %), 3 years (37 vs 64 %), and 5 years (20 vs 55 %) (P < 0.001). Patients with HCC and BDTT show lower OS than patients without BDTT. The higher frequency of liver stem cell marker expression in the presence of BDTT suggests that such stem cells may play a role in the pathogenesis of this form of HCC.

Caution for diagnosis and surgical treatment of recurrent cholangitis: lessons from 5 cases of bile duct tumor thrombus without a detectable intrahepatic tumor

The hepatocellular carcinoma (HCC) patients with bile duct tumor thrombus (BDTT) usually have no specific clinical symptoms at early stages. HCC with BDTT was usually misdiagnosed when the intrahepatic tumor was small, even undetectable. In this study, 5 cases of HCC with BDTT misdiagnosed as choledocholithiasis and cholangitis in the local hospital are described. We analyzed retrospectively and summarized our experiences of these 5 HCC patients with BDTT misdiagnosed in the local hospital during the past 5 years. The diagnosis, treatment, and outcome of the patients are discussed. Three patients underwent hepatectomy with thrombectomy and T-tube drainage. One patient underwent hepatectomy with the resection of the common bile duct and hepatojejunostomy, and palliative surgery was performed in 1 patient with portal vein tumor thrombus and intrahepatic metastasis. The patients were followed for 6-22 months; 4 patients died of tumor recurrence and metastasis or hepatic failure, despite 3 of these patients having received transhepatic arterial chemotherapy and embolization or radiofrequency ablation therapy. Early and accurate diagnosis of HCC with BDTT is very important. When patients have a history of abnormal recurrent cholangitis, HCC with BDTT should be highly suspected. Intraductal ultrasonography (US), intraoperative US, and histopathological examination are very valuable for the diagnosis. The prognosis of HCC patients with BDTT is dismal. Identification of this type of patient is clinically important, because surgical treatment may be beneficial.

Stages based molecular mechanisms for generating cholangiocytes from liver stem/progenitor cells

Except for the most organized mature hepatocytes, liver stem/progenitor cells (LSPCs) can differentiate into many other types of cells in the liver including cholangiocytes. In addition, LSPCs are demonstrated to be able to give birth to other kinds of extra-hepatic cell types such as insulin-producing cells. Even more, under some bad conditions, these LSPCs could generate liver cancer stem like cells (LCSCs) through malignant transformation. In this review, we mainly concentrate on the molecular mechanisms for controlling cell fates of LSPCs, especially differentiation of cholangiocytes, insulin-producing cells and LCSCs. First of all, to certificate the cell fates of LSPCs, the following three features need to be taken into account to perform accurate phenotyping: (1) morphological properties; (2) specific markers; and (3) functional assessment including in vivo transplantation. Secondly, to promote LSPCs differentiation, systematical attention should be paid to inductive materials (such as growth factors and chemical stimulators), progressive materials including intracellular and extracellular signaling pathways, and implementary materials (such as liver enriched transcriptive factors). Accordingly, some recommendations were proposed to standardize, optimize, and enrich the effective production of cholangiocyte-like cells out of LSPCs. At the end, the potential regulating mechanisms for generation of cholangiocytes by LSPCs were carefully analyzed. The differentiation of LSPCs is a gradually progressing process, which consists of three main steps: initiation, progression and accomplishment. It's the unbalanced distribution of affecting materials in each step decides the cell fates of LSPCs.

Tg737 inhibition results in malignant transformation in fetal liver stem/progenitor cells by promoting cell-cycle progression and differentiation arrest

Cancer stem/progenitor cells (CSPCs) may originate from the malignant transformation of normal stem cells. However, the mechanism by which normal stem cells undergo such transformation is not understood. Our previous studies provided evidence that Tg737 may play an important role in carcinogenesis of liver stem cells. In this study, we investigated the role of Tg737 in the malignant transformation of fetal liver stem/progenitor cells (FLSPCs). We inhibited Tg737 in FLSPCs using short hairpin RNA (shRNA). The microscopic observations of freshly purified Tg737 normal FLSPCs (nFLSPCs) and Tg737-silent FLSPCs (sFLSPCs), which showed high expression levels of stem cell markers, revealed no significant morphological changes in sFLSPCs. Following RNAi of Tg737, the mRNA and protein levels of sFLSPCs decreased by 81.81% and 80.10% as shown by PCR, Western blot and immunocytochemistry analyses. Excluding apoptosis-related effects, we found that silencing of Tg737 resulted in enhanced cell proliferation through promoting cell-cycle progression via upregulation of cyclin D1 and cyclin B expression (P < 0.05). Silencing of Tg737 also resulted in significant arrest of cell differentiation (P < 0.05), stable expression of both albumin (ALB) and alpha fetoprotein (AFP) (P > 0.05) and quiescent ultrastructure. Assessment of cell malignant traits by transwell migration assays and by growth of xenograft tumors in athymic mice showed that reduced expression of Tg737 greatly promoted cell invasion and hepatocarcinogenesis of FLSPCs (P < 0.05). This work shows that inactivation of Tg737 may play an important role in malignant transformation of FLSPCs.

A complex oncosurgical approach to increasing the resectability of colorectal cancer metastases - a case report

AIM

In this case report, the authors aim to demonstrate the success of recent methods in the radical treatment of a patient with primary inoperable liver and subsequent colorectal cancer pulmonary metastases.

METHODS

A 75 year old patient with inoperable bulky metastasis in the right hepatic lobe and insufficient future remnant liver volume was indicated for a stage procedure in the liver parenchyma. Embolization of the right branch of the portal vein was first performed with subsequent administration of stem cells into the contralateral liver lobe. Following compensatory growth of the left liver lobe, right-sided hepatectomy was performed with subsequent adjuvant oncological treatment. Six months after the surgery, a metastasis developed in the right pulmonary lobe which was solved by metastasectomy.

RESULTS

The patient, one year after the diagnosis of inoperable liver metastasis, is completely healthy and free of signs of disease recurrence.

CONCLUSION

A comprehensive oncosurgical approach using up-to-date diagnostic and treatment options may offer patients with metastatic colorectal cancer, radical treatment with the hope of long-term quality survival.

Tumors with macroscopic bile duct thrombi in non-HCC patients: Dynamic multi-phase MSCT findings

Non-hepatocellular carcinoma (non-HCC) with macroscopic bile duct tumor thrombus (BDTT) formation is rare, few radiological studies have been reported. In this case report, we retrospectively analyzed the imaging findings of three cases of non-HCC with macroscopic BDTT on dynamic enhanced multislice computed tomography (MSCT) scan. One case of primary hepatic carcinosarcoma was presented as a solitary, large well-defined tumor with significant necrotic changes. One case of liver metastasis from colon cancer was presented as a lobulated, large ill-defined tumor. One case of intraductal oncocytic papillary neoplasm involved the entire pancreas, presented as a cystic and solid mass with multilocular changes (the individual loculi were less than 5.0 mm in diameter). The bile duct was dilated due to expansible growth of the BDTT in all three patients. The BDTT was contiguous with hepatic or pancreatic tumor, and both of them showed the same enhancement patterns on dynamic contrast-enhanced computed tomography scan: early enhancement in the hepatic arterial phase and a quick wash-out of contrast agent in the portal and equilibrium phases. Macroscopic BDTT in non-HCC patient is rare, dynamic enhanced MSCT scan may be valuable in the diagnosis of non-HCC with BDTT.