Enhanced CD34 expression of sinusoid-like vascular endothelial cells in hepatocellular carcinoma

Single-cell RNA sequencing of cystic fibrosis liver disease explants reveals endothelial complement activation

BACKGROUND & AIMS

Cystic fibrosis (CF) is considered a multisystemic disorder in which CF-associated liver disease (CFLD) is the third most common cause of mortality. Currently, no effective treatment is available for CFLD because its pathophysiology is still unclear. Interestingly, CFLD exhibits identical vascular characteristics as non-cirrhotic portal hypertension, recently classified as porto-sinusoidal vascular disorders (PSVD).

METHODS

Since endothelial cells (ECs) are an important component in PSVD, we performed single-cell RNA sequencing (scRNA-seq) on four explant livers from CFLD patients to identify differential endothelial characteristics which could contribute to the disease. We comprehensively characterized the endothelial compartment and compared it with publicly available scRNA-seq datasets from cirrhotic and healthy livers. Key gene signatures were validated ex vivo on patient tissues.

RESULTS

We found that ECs from CF liver explants are more closely related to healthy than cirrhotic patients. In CF patients we also discovered a distinct population of liver sinusoidal ECs-coined CF LSECs-upregulating genes involved in the complement cascade and coagulation. Finally, our immunostainings further validated the predominant periportal location of CF LSECs.

CONCLUSIONS

Our work showed novel aspects of human liver ECs at the single-cell level thereby supporting endothelial involvement in CFLD, and reinforcing the hypothesis that ECs could be a driver of PSVD. Therefore, considering the vascular compartment in CF and CFLD may help developing new therapeutic approaches for these diseases.

Endothelial CD34 expression and regulation of immune cell response in-vitro

Endothelial cells cover the lining of different blood vessels and lymph nodes, and have major functions including the transport of blood, vessel homeostasis, inflammatory responses, control of transendothelial migration of circulating cells into the tissues, and formation of new blood vessels. Therefore, understanding these cells is of major interest. The morphological features, phenotype and function of endothelial cells varies according to the vascular bed examined. The sialomucin, CD34, is widely used as an endothelial marker. However, CD34 is differentially expressed on endothelial cells in different organs and in pathological conditions. Little is known about regulation of endothelial CD34 expression or function. Expression of CD34 is also strongly regulated in-vitro in endothelial cell models, including human umbilical vein endothelial cells (HUVEC) and endothelial colony forming cells (ECFC). We have therefore analysed the expression and function of CD34 by comparing CD34high and CD34low endothelial cell subpopulations. Transcriptomic analysis showed that CD34 gene and protein expressions are highly correlated, that CD34high cells proliferate less but express higher levels of IL-33 and Angiopoietin 2, compared with CD34low cells. Higher secretion levels of IL-33 and Angiopoietin 2 by CD34high HUVECs was confirmed by ELISA. Finally, when endothelial cells were allowed to interact with peripheral blood mononuclear cells, CD34high endothelial cells activated stronger proliferation of regulatory T lymphocytes (Tregs) compared to CD34low cells whereas expansion of other CD4+-T cell subsets was equivalent. These results suggest that CD34 expression by endothelial cells in-vitro associates with their ability to proliferate and with an immunogenic ability that favours the tolerogenic response.

Ectopic clotting factor VIII expression and misfolding in hepatocytes as a cause for hepatocellular carcinoma

Hemophilia A gene therapy targets hepatocytes to express B domain deleted (BDD) clotting factor VIII (FVIII) to permit viral encapsidation. Since BDD is prone to misfolding in the endoplasmic reticulum (ER) and ER protein misfolding in hepatocytes followed by high-fat diet (HFD) can cause hepatocellular carcinoma (HCC), we studied how FVIII misfolding impacts HCC development using hepatocyte DNA delivery to express three proteins from the same parental vector: (1) well-folded cytosolic dihydrofolate reductase (DHFR); (2) BDD-FVIII, which is prone to misfolding in the ER; and (3) N6-FVIII, which folds more efficiently than BDD-FVIII. One week after DNA delivery, when FVIII expression was undetectable, mice were fed HFD for 65 weeks. Remarkably, all mice that received BDD-FVIII vector developed liver tumors, whereas only 58% of mice that received N6 and no mice that received DHFR vector developed liver tumors, suggesting that the degree of protein misfolding in the ER increases predisposition to HCC in the context of an HFD and in the absence of viral transduction. Our findings raise concerns of ectopic BDD-FVIII expression in hepatocytes in the clinic, which poses risks independent of viral vector integration. Limited expression per hepatocyte and/or use of proteins that avoid misfolding may enhance safety.

Hepatocyte paraffin-1, CD10, and CD34 immunostaining as a diagnostic aid in cytologic diagnosis of hepatic cancer

Background

Cytomorphological distinction between hepatocellular carcinoma and metastatic tumors to the liver may be difficult, especially when these have poor differentiation. The present study was done to assess the diagnostic utility of hepatocyte paraffin-1 (HepPar-1), CD10, and CD34 in differentiating hepatocellular carcinoma from metastatic carcinoma.

Materials and Methods

Ultrasound-guided fine-needle aspiration was performed on 50 patients with space-occupying lesions of liver suspicious for malignancy on clinical/radiologic findings. The cytological assessment was done on smears stained with May-Grünwald-Giemsa and hematoxylin and eosin. Cell blocks were prepared, and immunostaining for HepPar-1, CD10, and CD34 was done.

Results

In these 50 patients, hepatocellular carcinoma was diagnosed in 7 and metastatic tumors in 43 cases. The sensitivity of smears in diagnosing hepatocellular carcinoma was 100% and the specificity was 95.3%, while the sensitivity and specificity of cell block were 100%. A canalicular pattern of CD10 immunoreactivity had a 100% positive predictive value for diagnosing hepatocellular carcinoma. CD10 had a sensitivity of 57.1% and 41.9% in identification of HCC and metastatic tumors, respectively. For the diagnosis of hepatocellular carcinoma, the sensitivity of CD34 was 85.7% and the specificity of sinusoidal pattern of immunoreactivity was 100%. The sensitivity and specificity of granular cytoplasmic staining pattern of HepPar-1 were 100% in hepatocellular carcinoma.

Conclusions

The staining patterns of HepPar-1, CD10, and CD34 are highly specific in distinguishing hepatocellular carcinoma from metastasis. These three immunomarkers should be included in the immunocytochemical panel for differentiating hepatocellular carcinoma from metastatic carcinoma to the liver.

Mechanism of paracrine communications between hepatic progenitor cells and endothelial cells

Hepatic progenitor cells (HPCs) are facultative tissue-specific stem cells lining reactive ductules, which are ubiquitously observed in chronic liver diseases and cancer. Although previous research mainly focused on their contribution to liver regeneration, it turned out that in vivo differentiation of HPCs into hepatocytes only occurs after extreme injury. While recent correlative evidence implies the association of HPCs with disease progression, their exact role in pathogenesis remains largely unknown. Our previous research demonstrated that HPCs expressing angiogenic paracrine factors accumulate in the peritumoral area and are positively correlated with the extent of intratumoral cell proliferation and angiogenesis in the livers of patients with liver cancer. Given the crucial roles of angiogenesis in liver disease progression and carcinogenesis, we aimed to test the hypothesis that HPCs secrete paracrine factors to communicate with endothelial cells, to determine molecular mechanisms mediating HPCs-endothelial interactions, and to understand how the paracrine function of HPCs is regulated. HPCs promoted viability and tubulogenesis of human umbilical vein endothelial cells (HUVECs) and upregulated genes known to be involved in angiogenesis, endothelial cell function, and disease progression in a paracrine manner. The paracrine function of HPCs as well as expression of colony stimulating factor 1 (CSF1) were inhibited upon differentiation of HPCs toward hepatocytes. Inhibition of CSF1 receptor partly suppressed the paracrine effects of HPCs on HUVECs. Taken together, our study indicates that inhibition of the paracrine function of HPCs through modulation of their differentiation status and inhibition of CSF1 signaling is a promising strategy for inhibition of angiogenesis during pathological progression.

Enabling perfusion through multicellular tumor spheroids promoting lumenization in a vascularized cancer model

A tumor is composed of heterogeneous cell population, which is known as tumor stroma. In particular, blood vessels have an indispensable role in the tumor microenvironment acting as a key player in anti-cancer drug delivery. Recently, efforts have been made to accurately recapitulate the microenvironment by employing distinct cell types, however, the proper formation of perfusable tumor tissue is challenging. Here, perfusable tumor tissue is engineered by implanting multicellular tumor spheroids inside the microfluidic devices. Blood perfusion, spheroid growth, and vascular dynamics were monitored according to the spheroid composition and the contribution of internal and external vascular cells to spheroid perfusion was analyzed. Most notably, the increased penetration depth of fluorescence conjugated anti-cancer drug was observed in tri-culture spheroids. The implementation of tumor microenvironment reconstruction developed in this study not only creates a perfusable tumor vascular model but can also be utilized as a novel drug screening platform with patient-derived samples.

Features of fibrosis regression abound in “non-cirrhotic” patients with resected hepatocellular carcinoma

Cirrhosis is a major risk factor for developing hepatocellular carcinoma (HCC). However, many surgically resected HCCs are presumably non-cirrhotic. The dynamic nature of chronic liver disease leads to periods of hepatic repair and fibrosis regression. We hypothesize that most resected HCCs, including those from non-cirrhotic patients, exhibit features of fibrosis regression in their background liver, suggesting previously more advanced liver disease. We reviewed the histology of 37 HCC resections performed between 2005–2020, including 30 from non-cirrhotic patients. The non-neoplastic liver was evaluated for features of liver disease and of the hepatic repair complex (HRC). CD34 immunohistochemistry was performed as a marker of sinusoidal capillarization. CD34 staining was evaluated manually and also by a digital image classifier algorithm. Overall, 28 cases (76%) had a high number of fibrosis regression and hepatic repair features (≥4 out of 8 features). Amongst the 30 non-cirrhotic patients, 21 (70%) showed a high number of repair features. Relative CD34 expression was increased in cases with a high number (≥4) of HRC features versus a low number (≤3) of features (p = 0.019). High HRC cases were more likely to exhibit nodular circumferential CD34 staining (p = 0.019). Our findings suggest that most resected HCC from non-cirrhotic patients display features of fibrosis regression in their background liver. Thus many, if not most, HCC patients who are “non-cirrhotic” may in fact have regressed cirrhosis. This finding reinforces that patients with regressed cirrhosis continue to be at high risk for HCC.

Tumor-associated macrophages in lung carcinoma: From mechanism to therapy

Tumor-associated macrophages (TAMs), which could be classified into the classical (M1-like) and alternatively activated (M2-like) phenotype, were considered to be important tumor-promoting components in lung cancer microenvironment. Several studies reported that TAMs in lung tumor islet or stroma are usually correlated with poor prognosis. Further studies showed that TAMs could promote the initiation of tumor cells, inhibit antitumor immune responses, and stimulate tumor angiogenesis and subsequently tumor metastasis of lung carcinoma. Currently, TAMs have been considered as penitential targets of lung cancer. This review summarizes from the fundamental information of TAMs to the its role in metastasis and present evidence for TAMs as a potential target of cancer therapy.

Role of liver sinusoidal endothelial cells in liver diseases

Liver sinusoidal endothelial cells (LSECs) form the wall of the hepatic sinusoids. Unlike other capillaries, they lack an organized basement membrane and have cytoplasm that is penetrated by open fenestrae, making the hepatic microvascular endothelium discontinuous. LSECs have essential roles in the maintenance of hepatic homeostasis, including regulation of the vascular tone, inflammation and thrombosis, and they are essential for control of the hepatic immune response. On a background of acute or chronic liver injury, LSECs modify their phenotype and negatively affect neighbouring cells and liver disease pathophysiology. This Review describes the main functions and phenotypic dysregulations of LSECs in liver diseases, specifically in the context of acute injury (ischaemia-reperfusion injury, drug-induced liver injury and bacterial and viral infection), chronic liver disease (metabolism-associated liver disease, alcoholic steatohepatitis and chronic hepatotoxic injury) and hepatocellular carcinoma, and provides a comprehensive update of the role of LSECs as therapeutic targets for liver disease. Finally, we discuss the open questions in the field of LSEC pathobiology and future avenues of research.

The Role of Immunocytochemical Markers to Differentiate Primary from Secondary Neoplastic Hepatic Masses: A Diagnostic Challenge on Cytology

OBJECTIVE

It is challenging and difficult to differentiate primary from metastatic hepatic masses solely on cytology. The present study aimed to correlate cytomorphological spectrum of hepatic masses with immunocytochemical markers to differentiate primary from metastases in liver.

MATERIAL AND METHOD

The present study comprised of 30 clinico-radiologically suspicious cases of neoplastic hepatic masses. Ultrasound-guided fine needle aspiration smears and cell blocks were prepared as per standard technique; two of the smears were air-dried and Giemsa stained to study cytomorphological features. A panel of markers (HepPar-1, CD 10, CK7, CK19, CD34, and MOC-31) were studied both in smears and cell blocks.

RESULTS

Cytomorphological features on smears were evaluated and correlated with immunocytochemistry in all cases; the final diagnosis was: Hepatocellular carcinoma (n=7), cholangiocarcinoma (n=2), hepatoblastoma (n=1) and metastatic carcinoma (n=20). HepPar-1, CD10 and CD34 demonstrated 86%, 72%, 86% sensitivity and 100% specificity respectively for hepatocellular carcinoma; CK7&CK19 showed 100% sensitivity for cholangiocarcinoma, MOC 31 showed 90% sensitivity and 100% specificity for metastatic carcinoma.

CONCLUSION

The present study recommends a panel of minimum three markers (HepPar-1, CD10, and MOC-31) which were helpful to differentiate hepatocellular carcinoma from metastatic carcinoma that was a major diagnostic challenge solely on cytomorphology. Correlating cytomorphology with these three markers, 100% of the cases could be diagnosed as primary malignancy and distinguished accurately from metastatic carcinoma.

A functional interaction between the CCR5 and CD34 molecules expressed in hematopoietic cells can support (or even promote) the development of cancer

Inflammation and angiogenesis are linked to the development of cancer since both can support the establishment of a tumor-prone microenvironment. The CCR5 is a major regulatory molecule involved in inflammation. The CD34 molecule is commonly described as a hematopoietic stem cell marker, and CD34⁺ cells are involved in the regulation of distinct physiological processes, including angiogenesis. CCR5 participates in the development of various types of cancer, and recently, a reduced CCR5 expression was associated with low CD34⁺ cell counts in human cord blood. A naturally occurring genetic variant of the CCR5 gene, the so-called CCR5Δ32 polymorphism, consists of a 32 base-pair deletion in the DNA, interfering in the CCR5 protein levels on the cell surface. When in homozygosis, this variant leads to a total absence of CCR5 expression on the cell surface. In heterozygous individuals, CCR5 surface levels are reduced. Based on these key findings, we hypothesize that a functional interaction can connect CCR5 and CD34 molecules (giving rise to a “CCR5-CD34 axis”). According to this, a CCR5-CD34 interaction can potentially support the development of different types of cancer. Consequently, the lack of CCR5 in association with reduced CD34⁺ cell counts could indicate a protective factor against the development of cancer. It is required to characterize in detail the functional relationship between CCR5 and CD34 proteins, as well as the real influence of both molecules on the susceptibility and development of cancer at population level. If our hypothesis is confirmed, the CCR5-CD34 axis may be a potential target in the development of anti-cancer therapies.

Microvessel Density and Clinicopathologic Characteristics in Hepatocellular Carcinoma with and without Cirrhosis

Angiogenesis is essential to the survival, growth, invasion, and metastasis of various human solid tumors. We compared the microvessel density (MVD) and clinicopathologic features of two different groups of hepatocellular carcinoma (HCC), namely HCC with cirrhosis (HCC-C) and without cirrhosis (HCC-NC). A tissue microarray composed of 20 normal livers, 20 cirrhotic livers, tumor and adjacent background non-neoplastic liver tissues from 20 HCC-C and 20 HCC-NC were constructed and stained immunohistochemically with antibodies against the antigen CD34. The MVD was determined by the measurement of the area and density of CD34 positive sinusoidal endothelial cells using the Image Pro Plus software. There was a trend of increased MVD in cirrhotic liver compared to normal liver and in cirrhotic background non-neoplastic liver adjacent to the tumor compared to the non-cirrhotic background non-neoplastic liver. Tumor tissue of HCC-C and HCC-NC both showed significantly higher MVD than their adjacent background non-neoplastic liver tissue. There was no statistical difference in MVD between HCC-C and HCC-NC. A higher value of MVD was seen in tumors of intermediate size (5–10 cm), high histologic grade, the presence of lymphvascular space invasion, and the underlying etiology of hepatitis C and alcoholic steatohepatitis. This data indicates that MVD may play an important role in liver carcinogenesis and neoplastic progression. The difference in clinical behavior between HCC-C and HCC-NC does not seem to be associated with differences in tumor MVD. Objective measurement of MVD using standardized computer software could potentially be used as a clinical marker to predict patients’ prognosis.

Mutually Supportive Mechanisms of Inflammation and Vascular Remodeling

Chronic inflammation is often accompanied by angiogenesis, the development of new blood vessels from existing ones. This vascular response is a response to chronic hypoxia and/or ischemia, but is also contributory to the progression of disorders including atherosclerosis, arthritis, and tumor growth. Proinflammatory and proangiogenic mediators and signaling pathways form a complex and interrelated network in these conditions, and many factors exert multiple effects. Inflammation drives angiogenesis by direct and indirect mechanisms, promoting endothelial proliferation, migration, and vessel sprouting, but also by mediating extracellular matrix remodeling and release of sequestered growth factors, and recruitment of proangiogenic leukocyte subsets. The role of inflammation in promoting angiogenesis is well documented, but by facilitating greater infiltration of leukocytes and plasma proteins into inflamed tissues, angiogenesis can also propagate chronic inflammation. This review examines the mutually supportive relationship between angiogenesis and inflammation, and considers how these interactions might be exploited to promote resolution of chronic inflammatory or angiogenic disorders.

Multidisciplinary perspective of hepatocellular carcinoma: A Pacific Northwest experience

Hepatocellular carcinoma (HCC) is the most rapidly increasing type of cancer in the United States. HCC is a highly malignant cancer, accounting for at least 14000 deaths in the United States annually, and it ranks third as a cause of cancer mortality in men. One major difficulty is that most patients with HCC are diagnosed when the disease is already at an advanced stage, and the cancer cannot be surgically removed. Furthermore, because almost all patients have cirrhosis, neither chemotherapy nor major resections are well tolerated. Clearly there is need of a multidisciplinary approach for the management of HCC. For example, there is a need for better understanding of the fundamental etiologic mechanisms that are involved in hepatocarcinogenesis, which could lead to the development of successful preventive and therapeutic modalities. It is also essential to define the cellular and molecular bases for malignant transformation of hepatocytes. Such knowledge would: (1) greatly facilitate the identification of patients at risk; (2) prompt efforts to decrease risk factors; and (3) improve surveillance and early diagnosis through diagnostic imaging modalities. Possible benefits extend also to the clinical management of this disease. Because there are many factors involved in pathogenesis of HCC, this paper reviews a multidisciplinary perspective of recent advances in basic and clinical understanding of HCC that include: molecular hepatocarcinogenesis, non-invasive diagnostics modalities, diagnostic pathology, surgical modality, transplantation, local therapy and oncological/target therapeutics.

Mobilization of endogenous bone marrow-derived stem cells in a thioacetamide-induced mouse model of liver fibrosis

The clinical significance of enhancing endogenous circulating haematopoietic stem cells is becoming increasingly recognized, and the augmentation of circulating stem cells using granulocyte-colony stimulating factor (G-CSF) has led to promising preclinical and clinical results for several liver fibrotic conditions. However, this approach is largely limited by cost and the infeasibility of maintaining long-term administration. Preclinical studies have reported that StemEnhance, a mild haematopoietic stem cell mobilizer, promotes cardiac muscle regeneration and remedies the manifestation of diabetes. However, the effectiveness of StemEnhance in ameliorating liver cirrhosis has not been studied. This study is the first to evaluate the beneficial effect of StemEnhance administration in a thioacetamide-induced mouse model of liver fibrosis. StemEnhance augmented the number of peripheral CD34-positive cells, reduced hepatic fibrosis, improved histopathological changes, and induced endogenous liver proliferation. In addition, VEGF expression was up-regulated, while TNF-α expression was down-regulated in thioacetamide-induced fibrotic livers after StemEnhance intake. These data suggest that StemEnhance may be useful as a potential therapeutic candidate for liver fibrosis by inducing reparative effects via mobilization of haematopoietic stem cells.

Aberrant centrizonal features in chronic hepatic venous outflow obstruction: centrilobular mimicry of portal-based disease

Chronic hepatic venous outflow obstruction is characterized by centrizonal scarring but may also display features that can lead to portal tract mimicry and misdiagnosis as biliary disease, especially given elevated cholestatic liver profiles in these patients. However, these histopathologic features have not been systematically described. We graded the numbers of centrizonal arterioles, ductules, keratin 7+ hepatocytes, CD34+ microvessels, and capillarized sinusoids in 61 cases of chronic venous outflow obstruction and assessed changes in metabolic zonation by glutamine synthetase staining. Centrizonal arterioles and ductules were present in 82.0% and 72.1% of cases, respectively, and correlated with fibrosis. Centrizonal CD34+ microvessels and sinusoidal capillarization were closely associated and present in 25 (92.6%) and 26 (96.3%) of 27 cases, respectively. Centrizonal capillarized sinusoids and microvessels, which were present in all cases with advanced fibrosis, were demonstrated in 90% and 80% of the cases without significant fibrosis, respectively. The results suggest that capillarization and/or microvessel formation precede and may contribute to centrizonal scarring, whereas arterialization likely reflects vascular remodeling associated with progressive fibrosis. Centrizonal ductules were often immature, being either keratin 7+/keratin 19- (36.4%) or keratin 7-/keratin 19- (10.0%). Centrizonal keratin 7+ intermediate-phenotype hepatocytes were present in 25 (92.5%) of 27 cases. Lastly, 22 (91.7%) of 24 cases showed loss of metabolic zonation, with reversed zonation in 2 (8.3%) cases. Together, the findings indicate that vascular and lobular reorganization in chronic venous outflow obstruction may result in mimicry of central zones as portal tracts. Recognition of these changes is essential to prevent misdiagnosis of this condition as biliary tract disease.

CD34 expression in noncancerous liver tissue predicts multicentric recurrence of hepatocellular carcinoma

BACKGROUND

Metachronous multicentric recurrence of hepatocellular carcinoma (HCC) is a common cause of morbidity and mortality following curative surgical resection. Clinical and laboratory predictors of these processes can markedly aid in managing these patients. Capillarization of hepatic sinusoids is also a well-known phenomenon in many liver diseases, especially in neoplastic liver diseases. Here, we investigated the clinical features, fibrosis scores and distribution of CD34 in noncancerous hepatic tissues of postresection patients with and without multicentric recurrence.

METHODS

Eighteen patients with multicentric recurrence of HCC diagnosed by histological examination of repeated hepatectomy specimens and 72 HCC patients with more than 5-year disease-free survival postresection participated in the study. We compared the clinicopathological features of these two groups. We examined noncancerous hepatic tissues for iron deposition by Prussian blue staining and computed the CD34-labeling index (LI) through immunohistochemistry using anti-CD34 antibody.

RESULTS

CD34-LI was significantly higher in the multicentric recurrence group (p < 0.001) and staging scores of fibrosis were also significantly higher in the recurrence group (p = 0.035). A high histological activity grade (p = 0.057) and a high alanine aminotransferase level (p = 0.060) were also associated with recurrence. There were no significant differences between the two groups in age, sex, hepatitis B virus surface antigen and anti-hepatitis C virus antibody levels, or grade of iron deposition. On multivariate analysis, high CD34-LI was the only independent risk factor (p = 0.001) for metachronous multicentric recurrence.

CONCLUSION

CD34 expression in the capillaries and sinusoids of noncancerous hepatic tissue is a risk factor for multicentric recurrence of HCC. Histologic assessment of hepatic tissue with CD34 immunohistochemistry might be useful for the prognostic evaluation of HCC patients after surgery.

Endothelial cells do not arise from tumor-initiating cells in human hepatocellular carcinoma

Background

Conventional models of carcinogenesis suggest that tumors recruit blood vessel formation from normal host tissues. This concept has recently been challenged by prominent studies of glioblastoma, which suggest that intratumoral endothelial cells (ECs) may arise from cancer stem cells/tumor-initiating cells (TICs). Hepatocellular carcinoma (HCC) is a common, highly vascularized tumor with few effective therapies, against which anti-angiogenic strategies are being actively explored. TICs are felt to play a role in HCC pathobiology, but their contributions to tumor vasculature have not been studied.

Methods

We examined human HCCs in settings that selected for tumor formation from functionally defined TICs, and in which the origin of intratumoral ECs from TICs as opposed to host tissues could be clearly distinguished. We generated HCC nodules in the livers of immunodeficient mice by intrasplenic injection of HCC cells from cell lines and patient specimens and studied the tumor ECs by immunohistochemistry for mouse and human markers. We then used immunohistochemistry for EC markers in combination with fluorescence in situ hybridization (FISH) for X and Y chromosomes to study the endothelium of recurrent HCC specimens resected from sex-mismatched liver allografts of patients who had undergone liver transplantation for HCC.

Results

We observed that all ECs in intrahepatic human HCC xenografts expressed mouse rather than human CD31. FISH analysis of recurrent HCCs resected from patients with sex-mismatched liver allografts revealed that all CD31⁺ and CD34⁺ intratumoral ECs originated from the donor allograft rather than the tumor.

Conclusions

These observations suggest that the vasculature of human HCC arises from normal host tissues rather than from TICs, supporting ongoing efforts to target angiogenesis in HCC as it is currently understood, and suggesting that the contribution of TICs to the vasculature of other cancers is disease-specific.

Autologous bone marrow mononuclear cell transplantation in patients with decompensated alcoholic liver disease: a randomized controlled trial

Objective

Impaired liver regeneration is associated with a poor outcome in patients with decompensated alcoholic liver disease (ALD). We assessed whether autologous bone marrow mononuclear cell transplantation (BMMCT) improved liver function in decompensated ALD.

Design

58 patients (mean age 54 yrs; mean MELD score 19, all with cirrhosis, 81% with alcoholic steatohepatitis at baseline liver biopsy) were randomized early after hospital admission to standard medical therapy (SMT) alone (n = 30), including steroids in patients with a Maddrey’s score ≥32, or combined with G-CSF injections and autologous BMMCT into the hepatic artery (n = 28). Bone marrow cells were harvested, isolated and reinfused the same day. The primary endpoint was a ≥3 points decrease in the MELD score at 3 months, corresponding to a clinically relevant improvement in liver function. Liver biopsy was repeated at week 4 to assess changes in Ki67+/CK7+ hepatic progenitor cells (HPC) compartment.

Results

Both study groups were comparable at baseline. After 3 months, 2 and 4 patients died in the BMMCT and SMT groups, respectively. Adverse events were equally distributed between groups. Moderate alcohol relapse occurred in 31% of patients. The MELD score improved in parallel in both groups during follow-up with 18 patients (64%) from the BMMCT group and 18 patients (53%) from the SMT group reaching the primary endpoint (p = 0.43 (OR 1.6, CI 0.49–5.4) in an intention to treat analysis. Comparing liver biopsy at 4 weeks to baseline, steatosis improved (p<0.001), and proliferating HPC tended to decrease in both groups (−35 and −33%, respectively).

Conclusion

Autologous BMMCT, compared to SMT is a safe procedure but did not result in an expanded HPC compartment or improved liver function. These data suggest either insufficient regenerative stimulation after BMMCT or resistance to liver regenerative drive in patients with decompensated alcoholic cirrhosis.

Trial Registration

Controlled-Trials.com ISRCTN83972743.

Recruitment of monocytes/macrophages in different tumor microenvironments

After emigration from the bone marrow into the peripheral blood, monocytes enter tissues and differentiate into macrophages. Monocytes/macrophages have many roles in immune regulation, angiogenesis, and tumor metastasis and invasion. In addition, studies have revealed that these cells are essential to tumor progression. Recently, an accumulation of evidence has indicated that macrophages in distinct regions of tumor masses have distinct origins. For instance, classical monocytes appear to be a major source of macrophages in tumor epithelial, perivascular, and hypoxic regions. In contrast, non-classical monocytes are an important source of macrophages in the tumor perivascular region. During the past century, it has been demonstrated that several chemoattractants can regulate the recruitment of monocytes/macrophages to tumor sites. Despite the importance of monocytes/macrophages in tumor progression, there had been, until recently, no efforts to summarize receptor-ligand pairs between tumor-derived chemokines and corresponding receptors in monocytes in different microenvironments. In this review, we present a cohesive view of the distinct expression patterns of chemokine receptors in two different monocyte subsets (classical and non-classical monocytes) and describe their roles in monocyte/macrophage recruitment into distinct tumor microenvironments. This review provides insight into the behavior of monocytes/macrophages in different tumor microenvironments.

Adipose derived mesenchymal stem cells transplantation via portal vein improves microcirculation and ameliorates liver fibrosis induced by CCl4 in rats

Introduction

Adipose derived mesenchymal stem cells (ADMSCs), carrying the similar characteristics to bone marrow mesenchymal stem cells, only much more abundant and easier to obtain, may be a promising treatment for liver fibrosis. We aim to investigate the therapeutic potential of ADMSCs transplantation in liver fibrosis caused by carbon tetrachloride (CCl₄) in rats as well as its underlying mechanism, and to further explore the appropriate infusion pathway.

Methods

ADMSCs were isolated, cultured and identified. Placebo and ADMSCs were transplanted via portal vein and tail vein respectively into carbon tetrachloride (CCl₄)-induced liver fibrosis rats. Computed tomography (CT) perfusion scan and microvessel counts were performed to measure the alteration of liver microcirculation after therapy. Liver function tests and histological findings were estimated.

Results

CT perfusion scan shown significant decrease of hepatic arterial perfusion index, significant increased portal vein perfusion, total liver perfusion in rats receiving ADMSCs from portal vein, and Factor VIII (FVIII) immunohistochemical staining shown significant decrease of microvessels in rats receiving ADMSCs from portal vein, indicating microcirculation improvement in portal vein group. Vascular endothelial growth Factor (VEGF) was significantly up-regulated in fibrosis models, and decreased after ADMSCs intraportal transplantation. A significant improvement of liver functional test and histological findings in portal vein group were observed. No significance was found in rats receiving ADMSCs from tail vein.

Conclusions

ADMSCs have a therapeutic effect against CCl₄-mediated liver fibrosis. ADMSCs may benefit the fibrotic liver through alteration of microcirculation, evidenced by CT perfusion scan and down-regulation of VEGF. Intraportal transplantation is a better pathway than tail vein transplantation.

Color-based tumor tissue segmentation for the automated estimation of oral cancer parameters

This article presents an automatic color-based feature extraction system for parameter estimation of oral cancer from optical microscopic images. The system first reduces image-to-image variations by means of color normalization. We then construct a database which consists of typical cancer images. The color parameters extracted from this database are then used in automated online sampling from oral cancer images. Principal component analysis is subsequently used to divide the color features into four tissue types. Each pixel in the cancer image is then classified into the corresponding tissue types based on the Mahalanobis distance. The aforementioned procedures are all fully automated; in particular, the automated sampling step greatly reduces the need for intensive labor in manual sampling and training. Experiments reveal high levels of consistency among the results achieved using the manual, semiautomatic, and fully automatic methods. Parameter comparisons between the four cancer stages are conducted, and only the mean parameters between early and late cancer stages are statistically different. In summary, the proposed system provides a useful and convenient tool for automatic segmentation and evaluation for stained biopsy samples of oral cancer. This tool can also be modified and applied to other tissue images with similar staining conditions.

Overexpression of EphA2, MMP-9, and MVD-CD34 in hepatocellular carcinoma: Implications for tumor progression and prognosis

AIM

To investigate the expression of erythropoietin-producing hepatocellular (Eph)A2 receptor, matrix metalloproteinase (MMP)-9, and angiogenesis in hepatocellular carcinoma (HCC), in order to reveal their expression correlations with tumor invasion, metastasis, and prognosis.

METHODS

From January 2000 to June 2003, 129 specimens of resected tumors from the patients with HCC were obtained. Corresponding pericarcinomatous liver tissues were also obtained and selected as a control group. Expressions of EphA2, MMP-9, and CD34 were detected with immunohistochemical staining. Microvascular density (MVD) was calculated with counting of CD34-positive vascular endothelial cells.

RESULTS

The expressions of EphA2, MMP-9, and MVD in the HCC tissues were significantly higher than those in the pericarcinomatous liver tissues (P < 0.01). Statistical analysis showed there were significant correlations between the expressions of EphA2, MMP-9 and MVD in some classicclinicopathological parameters (i.e. tumor nodule, vein invasion, tumor, node, metastasis stages, extrahepatic metastasis; P < 0.05). The correlation between EphA2 and MMP-9 expression was positive (r = 0.625, P = 0.011). Tumor MVD was closely associated with EphA2 (r = 0.281, P = 0.01) and MMP-9 (r = 0.319, P < 0.01) expressions. In particular, EphA2, MMP-9, and MVD expressions levels were found to be independent prognostic factors after HCC resection.

CONCLUSIONS

Overexpressions of EphA2 and MMP-9 relate to tumor progression, metastasis, and prognosis in HCC. The present study suggests that EphA2 is associated with key mediators of angiogenesis and invasion.

The relationship between enhanced intensity and microvessel density of gastric carcinoma using double contrast-enhanced ultrasonography

The purpose of this study was to assess the value of double contrast-enhanced ultrasound (DCUS), in which intravenous microbubbles are used together with an oral contrast agent as a method to evaluate the microvascular density (MVD) of gastric cancer, and its relationship with the contrast-enhanced intensity (EI) in gastric carcinomas. Sixty-nine patients with gastric cancer were examined preoperatively using DCUS. The arrival time (AT), time-to-peak (TTP), peak (PI) and baseline (pre-injection) intensities (BI) of gastric carcinoma and normal gastric wall were measured. Contrast-enhanced intensity (PI minus BI) was calculated. A monoclonal antibody against CD34 was used to display vascular endothelial cells in the resected gastric carcinoma specimens and in normal gastric mucosal tissues, and MVD was calculated by counting CD34-positive vascular endothelial cells. The differences in AT, TTP, EI and MVD between gastric carcinoma specimens and normal gastric wall tissues were evaluated using Student's t-test. The relationships between EI and MVD in gastric cancer were analyzed by Spearman rank correlation analysis. Both EI and MVD were significantly higher in gastric carcinomas than in normal gastric wall (p<0.001). However, AT and TTP showed no significant differences between gastric carcinoma specimens and normal gastric wall tissues (p>0.05). There was a strong positive linear correlation between EI and MVD in gastric carcinoma (r=0.921, p<0.001). Double contrast-enhanced ultrasound is a useful method for evaluation of the MVD in gastric carcinomas in vivo. Contrast-enhanced intensity has a strong positive linear correlation with MVD and could form a new index for assessing angiogenesis and the biological behavior of gastric carcinomas.

The antiangiogenic effect of thalidomide on occult liver metastases: an in vivo study in mice

AIM

To investigate the morphological changes of intratumoral microvessels after administration of thalidomide in occult hepatic metastases.

METHODS

Twenty mice with hepatic metastases created by injection of colon-26 tumor cells into the spleen were enrolled. Ten mice were treated with thalidomide (200 mg/kg) by intraperitoneal injection daily from the first day after inoculation of tumor cells, and the other 10 with saline only. Fifteen days after tumor cell inoculation, the intratumoral microvessels of hepatic metastases in both groups were studied by intravital microscopy and immunohistochemistry.

RESULTS

For the control group, although the intratumoral microvessel density (MVD) and CD34 positive microvessel density (MVD-CD34) of larger metastases (> 400 microm in diameter) were more than those of small metastases respectively (P < 0.01), the intratumoral branch density (BD) was similar to that of small metastases (P > 0.05). For the thalidomide treated group, despite the fact that MVD-CD34 of larger metastases was more than that of small metastases (P < 0.01), the MVD and BD were similar to those of small metastases respectively (P > 0.05). The MVD, BD and MVD-CD34 of small metastases of both groups were similar (P > 0.05); however, those of large metastases in the thalidomide treated group were significantly lower than those in the control group (P < 0.01).

CONCLUSIONS

Thalidomide exerts an antiangiogenic effect on occult hepatic metastases with angiogenesis only, and the different vascular components in the tumor vasculature demonstrate various responses to antiangiogenic therapy.

Differential vascular endothelial growth factor A protein expression between small hepatocellular carcinoma and cirrhosis correlates with serum vascular endothelial growth factor A and alpha-fetoprotein

BACKGROUND/AIMS

Drugs with antivascular endothelial growth factor A (anti-VEGF-A) action are under clinical evaluation with encouraging results in advanced hepatocellular carcinoma (HCC). The relative VEGF-A protein expression in non-advanced HCC and in the cirrhotic non-tumoral tissue in the same patient, a variable that could be important for treatment efficacy, has been investigated with conflicting results, only using the cirrhotic tissue surrounding the neoplasm (CS).

METHODS

We measured, for the first time, VEGF-A expression in non-advanced HCC and in the respective CS and cirrhotic tissue at a distance from the tumour (CD), in 24 patients who underwent liver transplantation.

RESULTS

VEGF-A protein was more expressed (P<0.05) in HCC than in CD, while no difference was found between HCC and CS. In HCC patients with a serum alpha-fetoprotein (AFP) higher than 20 ng/ml, VEGF-A protein expression in HCC was higher than in the corresponding CD in 83% of cases and AFP and serum VEGF-A corrected for the platelet count positively correlated with the differential VEGF-A protein expression between HCC and CD.

CONCLUSION

Our data provide a rationale for clinical trials involving anti-VEGF-A treatments in patients with non-advanced HCC, and suggest that serum AFP and VEGF-A are variables to be taken into account in these studies.

Angiopoietin-2 levels in the hepatic vein as a useful predictor of tumor invasiveness and prognosis in human hepatocellular carcinoma

BACKGROUND AND AIM

Hepatocellular carcinoma (HCC) is characteristically a hypervascular tumor and its progression is known to be closely related to angiogenesis. In this study, we investigated angiopoietin-2 (Ang-2) and vascular endothelial growth factor (VEGF) levels in the hepatic vein draining from HCC, as well as in the peripheral vein, to evaluate their relation to clinicopathological features and prognosis.

METHODS

To obtain hepatic venous blood samples, a catheter was placed into the main branch of the hepatic vein draining from HCC in 21 patients. The Ang-2 and VEGF levels in both the hepatic and peripheral veins were investigated. Furthermore, Ang-2 mRNA expression in surgically resected HCC was evaluated by quantitative reverse-transcription polymerase chain reaction (RT-PCR), as well as microvessel density (MVD) by CD34 immunostaining.

RESULTS

Ang-2 levels in the hepatic vein significantly correlated with Ang-2 mRNA expression in HCC, but Ang-2 levels in the peripheral vein did not correlate. Furthermore, a significant correlation was found between hepatic venous Ang-2 and MVD levels, whereas there was no significant correlation with hepatic venous VEGF levels. When hepatic venous Ang-2 levels were compared with clinicopathological features, a significant relationship was found between high Ang-2 levels and portal vein invasion. The survival for patients in the high hepatic venous Ang-2 group was significantly poorer when compared with the low group.

CONCLUSION

Preoperative hepatic venous Ang-2 levels may be a good predictor for portal vein invasion and also prognosis in patients with HCC.

Distinction of hepatocellular carcinoma from benign hepatic mimickers using Glypican-3 and CD34 immunohistochemistry

Distinguishing a well-differentiated hepatocellular carcinoma (HCC) from normal and cirrhotic liver tissue or benign liver nodules, such as hepatic adenoma (HA) and focal nodular hyperplasia (FNH), may be very difficult in some cases, particularly in small needle core biopsies. We studied the expression of Glypican-3 (GPC3) and CD34 in 107 cases of HCC, 19 cases of HA, and 16 cases of focal nodular hyperplasia (FNH). In addition, we studied GPC3 expression in 225 cases of nonhepatic human tumors with epithelial differentiation. Ninety-four of 107 cases (88%) of HCC showed focal or diffuse cytoplasmic GPC3 staining, whereas all HA and FNH cases were GPC3-negative, and only 7 of 225 cases (3%) of nonhepatic tumors with epithelial differentiation expressed GPC3. The sensitivity and specificity of GPC3 for HCC was 88% and 97%, respectively. There were three CD34 staining patterns observed in hepatic tissue: negative, incomplete positive, and complete positive. In negative staining pattern, only blood vessels in portal triads or rare sinusoidal spaces immediately adjacent to portal tracts were positive. The negative staining pattern was seen in normal or cirrhotic liver tissue only. The complete CD34 staining pattern showed virtually all sinusoidal spaces with CD34-positive staining throughout the lesion. The complete CD34 staining pattern was seen in virtually all cases of HCC and in only some cases of HA and FNH. The incomplete CD34 staining pattern was characterized by either CD34 positivity in virtually all sinusoidal spaces in some but not all nodules or CD34 positivity in the peripheral sinusoidal spaces adjacent to portal triads. The incomplete CD34 staining pattern was seen in rare cases of HCC and in most cases of HA and FNH. We conclude that GPC3 is a very specific marker not only for differentiating HCC from nonhepatic tumors with epithelial differentiation, but also for differentiating HCC from HA and FNH. GPC3 immunoreactivity, in combination with a complete CD34 immunostaining pattern, greatly facilitates the accuracy of distinguishing between malignant hepatic lesions and benign mimickers.

A color-based approach for automated segmentation in tumor tissue classification

This paper presents a new color-based approach for automated segmentation and classification of tumor tissues from microscopic images. The method comprises three stages: (1) color normalization to reduce the quality variation of tissue image within samples from individual subjects or from different subjects; (2) automatic sampling from tissue image to eliminate tedious and time-consuming steps; and (3) principal component analysis (PCA) to characterize color features in accordance with a standard set of training data. We evaluate the algorithm by comparing the performance of the proposed fully-automated method against semi-automated procedures. Experimental studies show consist agreement between the two methods. Thus, the proposed algorithm provides an effective tool for evaluating oral cancer images. It can also be applied to other microscopic images prepared with the same type of tissue staining.

Targeting stromal cells for the treatment of platelet-derived growth factor C-induced hepatocellular carcinogenesis

Non-invasive therapies for the treatment of hepatocellular carcinoma (HCC) would be of great benefit to public health. To this end, we have developed a platelet-derived growth factor-C (PDGF-C) transgenic (Tg) mouse model, which mimics many aspects of human liver carcinogenesis. Specifically, overexpression of PDGF-C results in liver fibrosis, which is preceded by activation and proliferation of hepatic stellate cells, and is followed by the development of dysplastic lesions and angiogenesis, and progression to HCCs by 8 months of age. Here, we show that PDGF-C overexpression induces the proliferation of endothelial-like cells that are present in tumors and adjacent non-neoplastic parenchyma. The protein tyrosine kinase inhibitor, imatinib (Gleevec), decreases the proliferation of non-parenchymal cells (NPC) in vitro and in vivo, with concomitant inhibition of Akt. In vivo treatment with imatinib also blocks the expression of CD34 in PDGF-C Tg mice. Decreased NPC proliferation and CD34 expression correlated with lower levels of active ERK1/2 and total levels of PDGF receptor alpha (PDGFRalpha). In summary, the small molecule inhibitor imatinib attenuates stromal cell proliferation in PDGF-C-induced HCC, which coincides with decreased expression of both CD34 and PDGFRalpha, and activated Akt. Our findings suggest that imatinib may be efficacious in the treatment of hepatocarcinogenesis, particularly when neovascularization is present.

Changes of Intratumoral Microvessels and Blood Perfusion during Establishment of Hepatic Metastases in Mice

PURPOSE

To prospectively evaluate the stepwise changes that occur in intratumoral microvessels and microcirculation during the establishment of murine colonic hepatic metastases by using in vivo fluorescent microscopy and to compare the changes with tumor angiogenesis evaluated with an immunohistochemical study.

MATERIALS AND METHODS

This study was approved by the institutional animal care and use committee. Twenty-five mice with hepatic metastases created with injection of murine colonic adenocarcinoma (colon 26) tumor cells into the spleen were examined with in vivo microscopy and immunohistochemical study for CD34, intracellular adhesion molecule (ICAM-1), and alpha smooth muscle actin (alpha-SMA). The tumor size, microcirculation in tumors, intratumoral microvessel density (MVD), afferent MVD, and CD34-positive MVD were evaluated. The data among the tumors that showed different hemodynamic or immunohistochemical patterns were compared with the Kruskal-Wallis test and the Student t test.

RESULTS

Four stepwise patterns were observed according to the changes in morphology, hemodynamics, and immunohistochemical characteristics of intratumoral microvessels during the establishment of hepatic metastases, as follows: metastases without definite intratumoral blood perfusion or any intratumoral microvessels (mean diameter, approximately 180 microm), metastases with portal perfusion and intratumoral ICAM-1-positive residual hepatic sinusoids (mean diameter, approximately 290 microm), metastases with mixed portal and arterial perfusion and increased CD34-positive microvessels and alpha-SMA-positive arterioles (mean diameter, approximately 520 microm), and metastases with exclusively arterial perfusion and increased CD34-positive microvessels and alpha-SMA-positive arterioles (mean diameter, >2000 microm). The differences among the mean sizes of the tumors that showed these four patterns were statistically significant (P < .01).

CONCLUSION

Stepwise changes of intratumoral microcirculation were revealed from direct diffusion, to portal perfusion, to mixed portal and arterial perfusion, and finally to arterial perfusion in accordance with stepwise tumor neovascularization during the growth of murine colonic hepatic metastases.

A cell-penetrating ARF peptide inhibitor of FoxM1 in mouse hepatocellular carcinoma treatment

The forkhead box m1 (Foxm1) transcription factor is essential for initiation of carcinogen-induced liver tumors; however, whether FoxM1 constitutes a therapeutic target for liver cancer treatment remains unknown. In this study, we used diethylnitrosamine/phenobarbital treatment to induce hepatocellular carcinomas (HCCs) in either WT mice or Arf(-/-)Rosa26-FoxM1b Tg mice, in which forkhead box M1b (FoxM1b) is overexpressed and alternative reading frame (ARF) inhibition of FoxM1 transcriptional activity is eliminated. To pharmacologically reduce FoxM1 activity in HCCs, we subjected these HCC-bearing mice to daily injections of a cell-penetrating ARF(26-44) peptide inhibitor of FoxM1 function. After 4 weeks of this treatment, HCC regions displayed reduced tumor cell proliferation and angiogenesis and a significant increase in apoptosis within the HCC region but not in the adjacent normal liver tissue. ARF peptide treatment also induced apoptosis of several distinct human hepatoma cell lines, which correlated with reduced protein levels of the mitotic regulatory genes encoding polo-like kinase 1, aurora B kinase, and survivin, all of which are transcriptional targets of FoxM1 that are highly expressed in cancer cells and function to prevent apoptosis. These studies indicate that ARF peptide treatment is an effective therapeutic approach to limit proliferation and induce apoptosis of liver cancer cells in vivo.

Podocalyxin-like protein 1 expression in primary hepatic tumours and tumour-like lesions

AIMS

The differential diagnosis of benign hepatic lesions and well-differentiated hepatocellular carcinomas can be a challenge, especially in small biopsy specimens. Recently, novel proteins expressed by the neovasculature in hepatocellular carcinoma (HCC) have been identified. The aim of this study was to compare the expression of podocalyxin-like protein 1 (PODXL1), a CD34-related sialomucin, in HCC and benign liver tumours or tumour-like lesions.

METHODS AND RESULTS

Vascular marker expression was examined using tissue microarrays as well as standard paraffin sections from formalin fixed paraffin-embedded liver tissue samples. Expression of PODXL1 was compared with anti-CD34, CD31 and von Willebrand factor VIII staining by immunohistochemistry. PODXL1 is expressed in tumour-associated microvasculature endothelial cells in HCC, as well as in capillarized sinusoidal endothelium of focal nodular hyperplasia (FNH) and hepatic adenoma. Expression in cirrhotic nodules correlates with CD34 and highlights endothelium in the inflow area. In dysplastic nodules CD34 and PODXL1 are not or only focally expressed.

CONCLUSIONS

Expression patterns of CD34 and PODXL1 are almost identical in primary hepatic tumours and tumour-like lesions. The presence of CD34+ and PODXL1+ sinusoidal endothelial cells aids in the diagnosis of HCC. Sinusoidal expression of PODXL1 is also seen in a less diffuse pattern in FNH and adenoma.

Human hepatic sinusoidal endothelial cells can be distinguished by expression of phenotypic markers related to their specialised functions in vivo

The hepatic sinusoids are lined by a unique population of hepatic sinusoidal endothelial cells (HSEC), which is one of the first hepatic cell populations to come into contact with blood components. However, HSEC are not simply barrier cells that restrict the access of blood-borne compounds to the parenchyma. They are functionally specialised endothelial cells that have complex roles, including not only receptor-mediated clearance of endotoxin, bacteria and other compounds, but also the regulation of inflammation, leukocyte recruitment and host immune responses to pathogens. Thus understanding the differentiation and function of HSEC is critical for the elucidation of liver biology and pathophysiology. This article reviews methods for isolating and studying human hepatic endothelial cell populations using in vitro models. We also discuss the expression and functions of phenotypic markers, such as the presence of fenestrations and expression of VAP-1, Stabilin-1, L-SIGN, which can be used to identify sinusoidal endothelium and to permit discrimination from vascular and lymphatic endothelial cells.

Correlation between CD105 expression and postoperative recurrence and metastasis of hepatocellular carcinoma

Background

Angiogenesis is one of the mechanisms most critical to the postoperative recurrence and metastasis of hepatocellular carcinoma (HCC). Thus, finding the molecular markers associated with angiogenesis may help identify patients at increased risk for recurrence and metastasis of HCC. This study was designed to investigate whether CD105 or CD34 could serve as a valid prognostic marker in patients with HCC by determining if there is a correlation between CD105 or CD34 expression and postoperative recurrence or metastasis.

Methods

Immunohistochemical staining for the CD105, CD34 and vascular endothelial growth factor (VEGF) antibodies was performed in 113 HCC tissue specimens containing paracarcinomatous tissue and in 14 normal liver tissue specimens. The quantitation of microvessels identified by anti-CD105 and anti-CD34 monoclonal antibodies and the semiquantitation of VEGF expression identified by anti-VEGF monoclonal antibody were analyzed in conjunction with the clinicopathological characteristics of the HCC and any available follow-up information about the patients from whom the specimens were obtained.

Results

CD105 was not expressed in the vascular endothelial cells of any normal liver tissue or paracarcinomatous liver tissue but was expressed in the vascular endothelial cells of all HCC tissue. In contrast, CD34 was expressed in the vascular endothelial cells of normal liver tissue, paracarcinomatous tissue, and HCC tissue in the following proportions of specimens: 86.7%, 93.8%, and 100%, respectively. The microvascular densities (MVDs) of HCC determined by using an anti-CD105 mAb (CD105-MVD) and an anti-CD34 mAb (CD34-MVD), were 71.7 ± 8.3 (SD) and 106.3 ± 10.4 (SD), respectively. There was a significant correlation between CD105-MVD and CD34-MVD (r = 0.248, P = 0.021). Although CD34-MVD was significantly correlated with VEGF expression (r = 0.243, P = 0.024), CD105-MVD was more closely correlated (r = 0.300, P= 0.005). The correlation between microscopic venous invasion and CD105-MVD, but not CD34-MVD, was also statistically significant (r = 0.254, P = 0.018). Univariate analysis showed that CD105-MVD was significantly correlated with the 2-year overall survival rate (P = 0.014); CD34-MVD was not (P = 0.601). Multivariate analysis confirmed that CD105-MVD was an independent prognostic factor and that CD34-MVD was not.

Conclusion

The anti-CD105 mAb is an ideal instrument to quantify new microvessels in HCC as compared with anti-CD34 mAb. CD105-MVD as compared with CD34-MVD is relevant a significant and independent prognostic indicator for recurrence and metastasis in HCC patients.

Clinicopathological and prognostic implications of endoglin (CD105) expression in hepatocellular carcinoma and its adjacent non-tumorous liver

AIM: The expression pattern of endoglin (CD105) in hepatocellular carcinoma (HCC) has not been reported so far. We hypothesized that CD105 could differentially highlight a subset of microvessels in HCC, and intratumoral microvessel density (IMVD) by CD105 immunostaining (IMVD-CD105) could provide better prognostic information than IMVD by CD34 immunostaining (IMVD-CD34).

METHODS: Paraffin blocks of tumor and adjacent non-tumorous liver tissues from 86 patients who underwent curative resection of HCC were used for this study. Serial sections were stained for CD105 and CD34, respectively, to highlight the microvessels. IMVD was counted according to a standard protocol.

RESULTS: In the HCC tissues, CD105 was either negatively or positively stained only in a subset of microvessels. In contrast, CD34 showed positive and more extensive microvessel staining in all cases examined. However, in the adjacent non-tumorous liver sections, CD105 showed a diffuse pattern of microvessel staining in 20 of 86 cases, while CD34 showed negative or only focal staining of the sinusoids around portal area. Correlation with clinicopathological data demonstrated that lower scores of IMVD-CD105 were found in larger sized tumors [mean 41.4/0.74 mm² (>5 cm tumor) vs 65.9/0.74 mm² (≤5 cm tumor), P = 0.043] and more aggressive tumors, as indicated by venous infiltration [36.8/0.74 mm² (present) vs 64.2/0.74 mm² (absent), P = 0.020], microsatellite nodules [35.1/0.74 mm² (present) vs 65.9/0.74 mm² (absent), P = 0.012], and advanced TNM tumor stage [38.8/0.74 mm² (stage 3 or 4) vs 68.3/0.74 mm² (stage 1 or 2), P = 0.014]. No prognostic significance was observed when median values were used as cut-off points using either IMVD-CD105 or IMVD-CD34. However, the presence of the diffuse pattern of CD105 expression in the adjacent non-tumorous liver tissues predicted a poorer disease-free survival (median 8.6 vs 21.5 mo, P = 0.026).

CONCLUSION: Our data demonstrate that a lower IMVD-CD105 is associated with larger and more aggressive tumors. In this study, IMVD-CD105 did not provide significant prognostic information. However, active angiogenesis as highlighted by diffuse CD105 staining of the microvessels in the adjacent non-tumorous liver tissues is predictive of early recurrence.

Novel endothelial cell markers in hepatocellular carcinoma

Hepatocellular carcinoma is characterized by hypervascularity and a propensity for vascular invasion. Detailed analysis of complementary DNA (cDNA) microarray global gene expression data and further validation on a smaller independent sample set by reverse transcription-polymerase chain reaction established the presence of two endothelial gene clusters in hepatocellular carcinoma. Cluster I, consists of 20 cDNA clones, representing 15 unique genes. Cluster II consists of nine unique genes. The expression of the cluster I genes appeared to be significantly upregulated in hepatocellular carcinoma compared with normal liver, cirrhotic liver, or nontumor liver tissues adjacent to the hepatocellular carcinoma. The pattern of gene expression of cluster I genes correlated positively with the 'proliferation gene cluster' and 'stromal cells cluster 2'. Expression of cluster II genes, in contrast, was not significantly different between hepatocellular carcinoma and non-neoplastic liver tissues. Studies conducted to localize the protein products of these genes by immunohistochemical staining of tissue arrays with up to 350 cores of tissues, and by in situ hybridization led to the discovery of novel sinusoidal endothelial cell markers in hepatocellular carcinoma: podocalyxin-like and regulator of G protein signaling-5. Our results underscore fundamental differences not only between neoplastic vs non-neoplastic liver cells but also between the hepatic sinusoidal endothelium of hepatocellular carcinoma and normal liver.

Immunohistochemical and molecular markers in the diagnosis of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) has distinct morphologic features and can be identified in the majority of cases by routine hematoxylin and eosin (H&E)-stained formalin-fixed paraffin-embedded sections. However, distinguishing a well-differentiated HCC from normal or regenerative tissue may be very difficult in some cases, particularly in small needle aspiration or core biopsies. Furthermore, some of the unusual morphologic variants, including clear-cell, pleomorphic, and sarcomatoid variants, may be mistaken for metastases. Similarly, metastases from various primary tumors to the liver may be mistaken for primary hepatic tumors. In this overview, we summarize the immunohistochemical and molecular markers that have been developed to address these diagnostic challenges. Among the numerous diagnostic markers studied, pCEA, HepPar 1, CD34, CK 7, CK 19, CK 20, and albumin in situ (ISH) have been found to be valuable in distinguishing HCC from metastatic neoplasms of extrahepatic sites.

Diagnostic value of HepPar1, pCEA, CD10, and CD34 expression in separating hepatocellular carcinoma from metastatic carcinoma in fine-needle aspiration cytology

Differentiating primary and metastatic hepatic malignancies can be diagnostically challenging in fine-needle aspiration cytology (FNAC). We compared four immunohistochemical (IHC) markers, pCEA, CD10, HepPar1, and CD34, in differentiating hepatocellular carcinoma (HCC) from metastatic carcinoma (MC) in FNAC specimens. Sixty cases of liver FNAC with their corresponding cell blocks were retrieved from the hospital computer system, including 30 HCC and 30 MC (15 colon, 10 breast, and 5 pancreas). The diagnoses were confirmed by clinical follow-up and surgical resection or core needle biopsy. The direct cytologic smears were air-dried and Diff-Quik-stained, and alcohol-fixed and Papanicolaou-stained. Cell block sections from the aspirates were immunostained for pCEA, CD10, HepPar1, and CD34. IHC on cytologic smears for HCC was performed on 10 cases and compared with the cell block results. In HCC, CD10, and pCEA demonstrated the characteristic canalicular staining in 23/30 (77%) and 24/30 (80%) of the cases, respectively; however, none of the MC showed a canalicular staining pattern. HepPar1 was positive in 26/30 (87%) of the HCC cases and one MC. CD34 stained sinusoidal endothelial cells in 27/30 (90%) cases of HCC and six MC. Our results demonstrate that the canalicular staining pattern for CD10 and sinusoidal staining pattern of CD34 are very specific, in addition to the high specificity and sensitivity of HepPar1 for HCC. Cell blocks were more informative in demonstrating the characteristic architecture and immunostaining pattern of the malignancy than the cytologic smears. An IHC panel consisting of pCEA, CD10, HepPar1, and CD34 is useful for confirming HCC in FNAC of the liver.

Endothelial cell differentiation in hepatocellular adenomas: implications for histopathological diagnosis

BACKGROUND/AIMS

Little information is available about the patterns of endothelial cell differentiation observed in hepatocellular adenomas. We therefore aimed to analyze the endothelial cell immunophenotype in a large series of these tumors and evaluate its possible diagnostic relevance.

METHODS

The expression of continuous and sinusoidal endothelial cell markers and of extracellular matrix proteins was analyzed by immunoperoxidase in 56 adenomas, as compared with 30 cases of focal nodular hyperplasia (FNH), 2 cases of telangiectatic FNH and 40 cases of hepatocellular carcinoma (HCC).

RESULTS

Twenty-eight adenomas (50%) presented a sinusoidal pattern of endothelial cell differentiation, characterized by the expression of specific sinusoidal endothelial cell markers and the presence of a subendothelial matrix resembling the normal perisinusoidal matrix. Eleven tumors (19.5%) presented a continuous pattern of endothelial cell differentiation. Seventeen tumors (30.5%) showed a mixed pattern. Twenty-eight FNH presented a sinusoidal pattern of endothelial cell differentiation; all HCC presented a continuous pattern of endothelial cell differentiation.

CONCLUSIONS

In hepatocellular adenomas, intra-tumoral vessels usually present a sinusoidal pattern of endothelial cell differentiation. However, the vascular phenotypic heterogeneity observed in our study questions the potential relevance of endothelial cell immunophenotyping for the differential diagnosis between hepatocellular adenomas and well differentiated HCC.

Angiogenesis in hepatocellular carcinoma: the retrospectives and perspectives

Hepatocellular carcinoma (HCC) is a typical hypervascular tumor. Many angiogenic factors have been studied in HCC, and several anti-angiogenic therapies have been tested in animal models and patients. This paper summarizes the latest findings, especially regarding the clinical significance of endothelial cell markers and angiogenic factors in HCC, and experimental and clinical anti-angiogenesis therapies. Further developments in this area, such as endothelial cell-oriented research and better experimental and clinical designs in the evaluation of anti-angiogenic therapies are discussed.

Microscopic vascular invasion detected by anti-CD34 immunohistochemistry as a predictor of recurrence of hepatocellular carcinoma after liver transplantation

BACKGROUND

Vascular invasion (VI) is the strongest risk factor for recurrence of hepatocellular carcinoma (HCC) after liver transplantation (LT). However, unlike macroscopic VI, microscopic VI has not been acknowledged as a predictor of recurrence in individual patients. This study aimed to determine whether immunohistochemical staining of the vessels could change the judgment on microscopic VI in such a way as to confer clinical relevance to the feature.

METHODS

Antibodies against the CD34 antigen (endothelial cell marker of hepatocarcinogenesis) were applied to sections from all the HCC nodules found in 136 patients who underwent LT for HCC arising from cirrhosis between 1990 and 2000. Microscopic VI at the periphery of the nodules was searched blindly by the same pathologist who had already examined hematoxylin-eosin slides. Several characteristics of the patients and of the cancers were analyzed to define their respective influence on recurrence.

RESULTS

Recurrent HCC was diagnosed in nine patients. Although 6 of the 22 patients in whom microscopic VI had been detected by hematoxylin-eosin staining developed recurrence, 8 of the 16 in whom microscopic VI was detected by anti-CD34 immunohistochemistry developed recurrence, accounting for 5-year cumulative incidences of recurrence of 34% and 70%, respectively. At multivariate analysis, relative risk for recurrence was the highest for microscopic VI found with anti-CD34 antibodies.

CONCLUSIONS

Microscopic VI detected by anti-CD34 immunohistochemistry implies an extremely high risk for HCC to recur after LT. Trials focusing on patients with evidence of microscopic VI are needed to test the efficacy of adjuvant therapies to prevent recurrence.

Tumoral angiogenesis and tissue factor expression during hepatocellular carcinoma progression in a transgenic mouse model

BACKGROUND/AIMS

The hypervascularity described in hepatocellular carcinoma varies according to the progression and the differentiation of the tumor, suggesting an angiogenic switch during tumor development.

METHODS

We used a transgenic mouse model of hepatocellular carcinoma induced by the expression of SV40-T antigen, in which male mice developed hepatic tumors at various temporal and histological stages, whereas female mice remained tumor-free. We analyzed, by immunostaining and reverse transcription-polymerase chain reaction, factors involved in tumoral angiogenesis.

RESULTS

We demonstrated that tumoral angiogenesis occurred before the development of diffuse hepatocarcinoma. We showed that some SV40-T-positive cells with an endothelial phenotype are involved in angiogenic processes, suggesting a partial vasculogenic mimicry. This tumoral angiogenesis is associated with platelet activation due to tissue factor expression in endothelial cells and invading macrophages. Normal and transgenic livers exhibited different pattern of expression of hypoxia-inducible factor 1 alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) mRNA.

CONCLUSIONS

This model of hepatocellular carcinoma displays marked tumoral angiogenesis, with proliferation, remodeling and arterialization of hepatic sinusoids, probably associated with a partial vasculogenic mimicry. Abnormal angiogenesis observed in hepatocarcinoma was associated with platelet activation by tissue factor (TF) produced by endothelial cells and invading macrophages. In this transgenic model, HIF-1alpha, VEGF, and TF play a crucial role in tumoral angiogenesis.

Expression of the endothelial markers PECAM-1, vWf, and CD34 in vivo and in vitro

EC culture models are essential to study pathological alterations of endothelial cells (ECs) in pulmonary vascular diseases under standardized conditions. Nevertheless, little is known about the spectrum of alterations of vessel-specific endothelial phenotypes in monolayer cultures. For the comparative study of endothelial markers in vivo and in vitro we investigated immunohistochemically the expression of PECAM-1, vWf, and CD34 by pulmonary ECs in vivo and in stimulated/unstimulated human umbilical vein endothelial cells (HU-VEC) and human pulmonary microvascular endothelial cells (HPMEC). In vivo, vessel type-specific expression patterns were found for vWf and CD34, while PECAM-1 was homogeneously and strongly expressed. While all HUVEC showed a marked vWf staining, about two-thirds of HPMEC exhibited a strong and the rest a moderate vWf staining. In both in vitro models all ECs were clearly PECAM-1-positive. However, only about 20% of the HUVEC and HPMEC were CD34-positive. Our results demonstrate the reduced expression of vessel type-specific endothelial phenotypes by endothelial monolayer cultures, stressing the need to improve culture conditions as well as develop cocultures and three-dimensional culture models. Moreover, the need for endothelial markers specific for single microvascular type ECs becomes obvious in order to establish cultures consisting of only one microvascular ECs subpopulation.

Tumor microvessel density as a predictor of recurrence after resection of hepatocellular carcinoma: a prospective study

PURPOSE

This study prospectively evaluated the correlation of tumor microvessel density (MVD) with clinicopathologic features and postoperative recurrence in patients undergoing resection of hepatocellular carcinoma (HCC).

PATIENTS AND METHODS

Tumor MVD was assessed in 100 patients with resection of HCC using a computer image analyzer after immunostaining for CD34 (MVD-CD34) and von Willebrand factor (MVD-vWF), respectively. Patients were prospectively followed for recurrence.

RESULTS

Mean tumor MVD-CD34 (236/0.74 mm(2)) was higher than mean tumor MVD-vWF (87/0.74 mm(2)) (P <.001). By multiple regression analysis, tumor size was the only pathologic feature significantly related to tumor MVD-CD34. The median MVD-CD34 was 316/0.74 mm(2) in HCCs < or = 5 cm (n = 46) and 146/0.74 mm(2) in HCCs more than 5 cm (n = 54) (P <.001). Among patients with HCCs < or = 5 cm, those with higher than median MVD-CD34 had worse disease-free survival (at 3 years, 13%) than those with a lower MVD-CD34 (at 3 year, 74%) (P =.002). Multivariate analysis showed that tumor MVD-CD34 was the only significant factor predictive of disease-free survival in patients with HCC < or = 5 cm. For HCCs more than 5 cm, MVD-CD34 did not have a significant prognostic influence. MVD-vWF did not have a significant prognostic influence on disease-free survival in either HCCs < or = 5 cm or more than 5 cm.

CONCLUSION

This study shows that a high MVD-CD34 was predictive of early postresection recurrence in patients with HCCs < or = 5 cm and, therefore, may be a novel prognostic marker in this subset of patients.

Expression of smooth muscle calponin in tumor vessels of human hepatocellular carcinoma and its possible association with prognosis

BACKGROUND

Hepatocellular carcinoma (HCC) is a vascular-rich tumor. The tumor vessels in HCC were demonstrated to have alpha-smooth muscle actin positive smooth muscle cells (SMCs). However, it is unclear whether the SMCs in the wall of the tumor vessels are differentiated or undifferentiated. Basic calponin is an actin-, tropomyosin-, and calmodulin-binding protein, and expression of the calponin gene in SMCs has been recognized as one of the late stage differentiation markers of SMCs. The authors investigated the differentiation state of SMCs in tumor vessels by immunohistochemical examination of calponin in patients with HCC, and whether it is associated with the patients' prognosis.

METHODS

Tumor and nontumor tissues were obtained from 75 patients with HCC who underwent radical hepatic resection. The differentiation state of the smooth muscle cells were evaluated based on the expression level of calponin, an actin-binding protein, using immunohistochemistry and reverse transcription-polymerase chain reaction analysis. The disease free survival (DFS) rates were estimated according to the Kaplan-Meier method comparing groups of patients with calponin positive and negative tumor vessels. A multivariate analysis based on the Cox proportional hazards regression model was performed to estimate whether the expression of calponin is an independent prognostic factor.

RESULTS

In the 75 patients with HCC examined, 36 patients (48%) possessed calponin positive SMCs, and the remaining 39 (52%) did not. There were no significant differences in either clinical or pathologic factors between the two groups of patients. The 5- and 8-year DFS rate of the patients with calponin positive vessels were 37% and 26%, respectively. These values were significantly higher (11% and 5%) than those of patients with calponin negative vessels. Gender, TNM classification, perioperative transfusion, and calponin expression were found to be independent prognostic factors for DFS.

CONCLUSIONS

Immunohistochemical examination of the calponin expression in the tumor vessels is a new and useful means to predict the prognosis of HCC patients after hepatic resection.