Endothelial cell marker expression in dysplastic lesions of the liver: an immunohistochemical study

CAF-induced placental growth factor facilitates neoangiogenesis in hepatocellular carcinoma

As a highly malignant tumor, hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide. In most HCC patients, the development of HCC begins with hepatitis, which is followed by fibrosis and cirrhosis before progressing to HCC. Cancer-associated fibroblasts (CAFs), which are generally believed to be derived from activated hepatic stellate cells (HSCs), are highly involved in the development of HCC through the secretion of cytokines and angiogenic factors. The results of our study showed that a considerable number of CAFs highly expressed CD90 and were enriched in HCC tissues. Bioinformatics analysis of the transcriptome of HCC tissues revealed that placental growth factor (PlGF) is significantly correlated with CD90 expression. The isolated primary CAFs and activated HSCs overexpressed PlGF and CD90. In addition, the results of gene expression profiling interactive analysis based on The Cancer Genome Atlas showed that high levels of both PlGF and CD90 are correlated with tumor angiogenesis markers (CD31, CD34, and CD105) and predict poor HCC patient prognosis. In summary, our results suggest that CAFs can generate PlGF and may provide an effective target for CAFs-regulated neoangiogenesis in HCC.

Recurrence of Hereditary Hemorrhagic Telangiectasia After Liver Transplantation: Clinical Implications and Physiopathological Insights

Liver transplantation (LT) has been proposed as a curative treatment in hereditary hemorrhagic telangiectasia (HHT) with severe hepatic involvement. We provide a long-term evaluation of graft status after LT for HHT, with a focus on the risk of recurrence. The present study included all patients prospectively followed up after LT for HHT in the Lyon Liver Transplant Unit from 1993 to 2010, with a survival of more than 1 year. Protocol clinical, radiological, and histological examinations were performed at regular intervals. Fourteen patients were included (13 women and one man). Median age at LT was 52.5 years (range: 33.1-66.7). In eight patients (seven female), disease recurrence was diagnosed by abnormal radiological features, suggestive of microcirculatory disturbances. Typical vascular lesions, including telangiectasia, were demonstrated by liver biopsy in five of these patients. The median interval between LT and diagnosis of recurrence was 127 months (range: 74-184). The risk of recurrence increased over time; estimated cumulative risk was 47.9% at 15 years. Liver tissue analysis found the coexistence of an angiogenic process combined with endothelial microchimerism, as shown by the presence of vascular lining cells of recipient origin. Conclusion: The present data show that disease recurrence occurs, usually after a long delay, in a significant number of patients treated by LT for liver complications of HHT. This strongly supports the necessity of a lifelong follow-up and suggests that therapeutic strategy needs discussion and evaluation, especially of the role of potential adjuvant treatments to LT, such as antiangiogenic medications, when recurrent disease appears.

Immunohistochemical Expression of CD31 (PECAM-1) in Nonendothelial Tumors of Dogs

CD31 immunoreactivity has been reported in human nonendothelial tumors of both epithelial and mesenchymal origin. This study examined CD31 immunoreactivity of 347 formalin-fixed, paraffin-embedded normal, nonneoplastic, and neoplastic canine tissues. CD31 expression was considered positive if at least 10% of the cell population had membranous reactivity. Labeling with the CD31 antibody (clone JC/70A) was observed in 16 samples of normal organs (liver, kidney, lymph node), 6 of 6 specimens of hepatic nodular hyperplasia, 3 of 3 hepatic regenerative nodules, 1 of 4 anal sac carcinomas, 6 of 6 hemangiosarcomas, 18 of 20 hepatocellular carcinomas, 1 of 6 mammary carcinomas, 3 of 5 plasmacytomas, 18 of 53 renal cell carcinomas, and 1 of 5 cutaneous histiocytomas. CD31 expression did not correlate with case outcome in hepatocellular or renal cell carcinomas. Although distinguishing hemangiosarcoma from other neoplasms is typically straightforward, pathologists should be aware of potential cross-reactivity when relying on CD31 immunohistochemistry for diagnosis, particularly in small biopsy samples or when faced with an epithelioid or poorly differentiated vascular neoplasm.

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.

Practical Immunohistochemistry in Neoplastic Pathology of the Gastrointestinal Tract, Liver, Biliary Tract, and Pancreas

CONTEXT

- Immunomarkers with diagnostic, therapeutic, or prognostic values have been increasingly used to maximize the benefits of clinical management of patients with neoplastic diseases of the gastrointestinal tract, liver, biliary tract, and pancreas.

OBJECTIVES

- To review the characteristics of immunomarkers that are commonly used in surgical pathology practice for neoplasms of the gastrointestinal tract, liver, biliary tract, and pancreas, and to summarize the clinical usefulness of immunomarkers that have been discovered in recent years in these fields.

DATA SOURCES

- Data sources include literature review, authors' research data, and personal practice experience.

CONCLUSIONS

- Immunohistochemistry is an indispensable tool for the accurate diagnosis of neoplastic diseases of the gastrointestinal tract, liver, biliary tract, and pancreas. Useful immunomarkers are available to help distinguish malignant neoplasms from benign conditions, determine organ origins, and subclassify neoplasms that are morphologically and biologically heterogeneous. Specific immunomarkers are also available to help guide patient treatment and assess disease aggressiveness, which are keys to the success of personalized medicine. Pathologists will continue to play a critical role in the discovery, validation, and application of new biomarkers, which will ultimately improve patient care.

[Vascularization of hepatoceliular carcinoma]

The paper gives the data available in the literature on vascularization of hepatocellular carcinoma (HCC). Sinusoidal capillarization and unpaired arteries are shown to play an important role in the development and progression of HCC. The density of microvessels detected by immunohistochemical techniques is a morphological indicator of the degree of angiogenic processes. Higher-grade HCC is followed by changes in its vascularization and concurrent with a progressive increase in the proportion of blood entering along the hepatic artery. The morphological indicators of microvessel density are recommended to use as addi- tional criteria for determining the prognosis of the disease, designing targeted anti-angiogenic drugs, and evaluating the efficiency of performed therapy.

Combination of sorafenib and angiotensin-II receptor blocker attenuates preneoplastic lesion development in a non-diabetic rat model of steatohepatitis

BACKGROUND

Given the well-documented adverse side effects of sorafenib, many sorafenib-treated patients may need the reduced initial dose of the compound, and an alternative sorafenib-based therapy, which exerts similar clinical benefit, is anticipated. An angiostatic therapy with sorafenib is considered one of the promising approaches for chemoprevention of hepatocellular carcinoma. The aim of the current study was to elucidate the combination effect of low dose of sorafenib and angiotensin-II receptor blocker (ARB) on hepatocarcinogenesis, especially in conjunction with angiogenesis.

METHODS

The chemopreventive effect on the development of liver preneoplastic lesions, angiogenesis, and several indices was elucidated in rats. We also performed several sets of in vitro experiments to examine the mechanisms involved.

RESULTS

Using a non-diabetic rat model of steatohepatitis with choline deficient L-amino acid-defined diet, sorafenib demonstrated marked inhibition of preneoplastic lesions in a dose dependent manner. Combined treatment with ARB (losartan) at a clinically comparable dose and half dose of sorafenib resulted in the inhibitory effect equivalent to that of common dose of sorafenib along with suppression of hepatic neovascularization and potent angiogenic factor, vascular endothelial growth factor. Furthermore, similar combined inhibitory outcomes were observed in several sets of in vitro studies.

CONCLUSION

Since the combinatorial treatment using low doses of sorafenib and ARB could sufficiently induce inhibitory effect on the development of preneoplastic lesions at the magnitude similar to the conventional dose of sorafenib, this regimen may provide new strategy for patients intolerant of the usual dose of sorafenib in the future.

Endogenous antibodies for tumor detection

The study of cancer immunology has provided diagnostic and therapeutic instruments through serum autoantibody biomarkers and exogenous monoclonal antibodies. While some endogenous antibodies are found within or surrounding transformed tissue, the extent to which this exists has not been entirely characterized. We find that in transgenic and xenograft mouse models of cancer, endogenous gamma immunoglobulin (IgG) is present at higher concentration in malignantly transformed organs compared to non-transformed organs in the same mouse or organs of cognate wild-type mice. The enrichment of endogenous antibodies within the malignant tissue provides a potential means of identifying and tracking malignant cells in vivo as they mutate and diversify. Exploiting these antibodies for diagnostic and therapeutic purposes is possible through the use of agents that bind endogenous antibodies.

Evaluation and comparison of microvessel density using the markers CD34 and CD105 in regenerative nodules, dysplastic nodules and hepatocellular carcinoma

PURPOSE

The progression of hepatocellular carcinoma (HCC) is multifactorial and angiogenesis plays a fundamental role, mainly because HCC is a highly vascularized tumor.

METHODS

In this study, we determined microvessel density (MVD) using the immunohistochemical markers, CD34 and CD105 (Endoglin), in 44 hepatectomy specimens, encompassing 44 malignant nodules (HCC), 44 regenerative nodules (RN), and 15 dysplastic nodules (DN). The evaluation included the determination of MVD in all nodules. For statistical analysis, a descriptive analysis was carried out using measurements of position and dispersion for continuous variables; ANOVA was used to compare between groups, considering p < 0.05 as statistically significant.

RESULTS

We observed a significant difference when comparing CD34 and CD105 immunoexpression in HCC, DN, and RN. CD105 was predominantly expressed in the peripheral regions in HCC, with mean MVD scores of 6.2 ± 4.1 and 10.7 ± 4.4 at the center and periphery of the nodules, respectively, with significant differences between groups (p < 0.0001). CD34 had higher mean MVD scores than CD105 in HCC, with a more uniform positivity pattern. CD105 immunoexpression in DN exhibited a pattern similar to HCC. However, in RN, CD105 exhibited a higher MVD score in the central portion of the nodules. CD105 was expressed in a subset of newly formed microvessels in HCC and demonstrated an elevated mean MVD in cirrhotic or regenerative nodules.

CONCLUSIONS

MVD determined by CD34 and CD105 expression may be used as an additional parameter to distinguish benign from malignant liver nodules.

Direct renin inhibitor, aliskiren, attenuates the progression of non-alcoholic steatohepatitis in the rat model

AIM

Renin is a rate-limiting enzyme of the renin-angiotensin system (RAS), and several reports have shown that renin plays an important role in several pathological processes. Although RAS is known to play a pivotal role in the progression of non-alcoholic steatohepatitis (NASH), the role of renin is still obscure. The aim of the current study was to examine the effect of the clinically used direct renin inhibitor (DRI), aliskiren, on the progression of NASH in a rat model.

METHODS

The effects of DRI on the choline-deficient L-amino acid-defined (CDAA) diet-induced rat NASH model was examined in conjunction with the activated hepatic stellate cells (Ac-HSC) and neovascularization, both of which are known to play important roles in liver fibrosis development and hepatocarcinogenesis, respectively.

RESULTS

DRI exerted a marked inhibitory effect against liver fibrosis development and glutathione-S-transferase placental form (GST-P) positive preneoplastic lesions along with suppression of the Ac-HSC and neovascularization in a dose-dependent manner. DRI also inhibited the hepatic expressions of transforming growth factor-beta 1 (TGF-beta 1), angiotensin-II (AT-II) and vascular endothelial growth factor (VEGF). These results indicated that renin played a pivotal role in the liver fibrosis development and hepatocarcinogenesis of NASH.

CONCLUSION

Because DRI is already widely used in the clinical practice with safety, this drug may represent a potential new strategy against the progression of NASH in the future.

Dual blockade of angiotensin-II and aldosterone suppresses the progression of a non-diabetic rat model of steatohepatitis

AIM

Both angiotensin-II (AT-II) and aldosterone (Ald) play pivotal roles in the pathogenesis of diseases in several organs including the liver. We previously reported that suppression of AT-II and Ald with angiotensin-converting enzyme inhibitor (ACE-I) and selective Ald blocker (SAB), respectively, attenuated the rat liver fibrogenesis and hepatocarcinogenesis. The aim of our current study was to elucidate the combined effects of ACE-I and SAB in the progression of a non-diabetic rat model of steatohepatitis, and the possible mechanisms involved.

METHODS

In the choline-deficient L-amino acid-defined (CDAA) diet-induced model, the effects of ACE-I and SAB on liver fibrosis development and hepatocarcinogenesis were elucidated, especially in conjunction with neovascularization.

RESULTS

Treatment with both ACE-I and SAB suppressed the development of liver fibrosis and glutathione-S-transferase placental form (GST-P) positive pre-neoplastic lesions. The combined treatment with both agents exerted more inhibitory effects as compared with either a single agent along with suppression of the activated hepatic stellate cells (Ac-HSC) and neovascularization, both of which play important roles in these processes. Our in vitro study showed that AT-II type 1 receptor blocker (ARB) and SAB inhibited Ac-HSC proliferation and in vitro angiogenesis along with suppression of the in vivo studies.

CONCLUSION

Dual blockade of AT-II and Ald suppresses the progression of a non-diabetic rat model of steatohepatitis. Because both agents are widely and safely used in clinical practice, this combination therapy could be an effective new strategy against steatohepatitis in the future.

Branched-chain amino acids suppress the cumulative recurrence of hepatocellular carcinoma under conditions of insulin-resistance

Branched-chain amino acids (BCAAs) reportedly inhibit the incidence of hepatocellular carcinoma (HCC) in patients with liver cirrhosis and obesity that is frequently associated with insulin resistance (IR). We previously reported that BCAAs exert a chemopreventive effect against HCC under IR conditions in rats. The aim of the present study was to examine the effect of BCAAs on the cumulative recurrence of HCC under IR conditions in the clinical practice. BCAA granules (Livact^®, 12 g/day) were administered for 60 months following the local curative therapy for HCC, and several indices were determined. Treatment with BCAAs markedly inhibited the cumulative recurrence of HCC in patients with a high IR index [homeostasis model assessment (HOMA)-IR >2.5], but not in patients with HOMA-IR of ≤2.5. BCAA also improved the HOMA-IR, and the inhibitory effect was observed regardless of the serum albumin (Alb) levels. Similarly, BCAA treatment revealed a marked suppressive effect in patients with high fasting insulin [immune reactive insulin (IRI) >15 U/ml], but not with IRI of ≤15. BCAA treatment did not result in differences in HCC recurrence in patients with high and low glucose levels [fasting blood sugar (FBS) >110 and ≤110, respectively]. Furthermore, serum levels of the soluble form of vascular endothelial growth factor receptor 2 (sVEGFR2) were significantly inhibited along with these clinical effects. Our findings indicate that the inhibitory effect of BCAAs was achieved, at least partly, by coordinated effects of anti-angiogenesis and IR improvement. Since BCAAs are widely and safely used in clinical practice to treat patients with chronic liver diseases, BCAAs may represent a new strategy for secondary chemoprevention for HCC patients with IR. Moreover, our findings suggest that sVEGFR2 may be a useful clinical predictive marker for BCAA treatment under IR conditions.

Diagnostic value of immunohistochemical staining of GP73, GPC3, DCP, CD34, CD31, and reticulin staining in hepatocellular carcinoma

It has been reported that Golgi protein-73 (GP73), glypican-3 (GPC3), and des-γ-carboxy prothrombin (DCP) could serve as serum markers for the early detection of hepatocellular carcinoma (HCC). This study aimed to evaluate a panel of immunostaining markers (including GP73, GPC3, DCP, CD34, and CD31) as well as reticulin staining to distinguish HCC from the mimickers. Our results revealed that CD34 immunostaining and reticulin staining were highly sensitive for the diagnosis of HCC. A special immunoreaction pattern of GP73--a diffuse coarse-block pattern in a perinuclear region or a concentrated cluster-like or cord-like pattern in a certain part of the cytoplasm--was observed in HCC cells, in contrast to the cytoplasmic fine-granular pattern in surrounding non-tumor cells and non-malignant nodules. This coarse-block pattern correlated significantly with less differentiated HCC. In comparison, GPC3 displayed a good advantage in diagnosing well-differentiated HCC. In our study, DCP and CD31 showed little diagnostic value for HCC as an immunostaining marker. When GP73, GPC3, and CD34 were combined, the specificity improved to 96.6%. Our findings demonstrate for the first time that the immunohistochemical panel of GP73, GPC3, and CD34 as well as reticulin staining is highly specific for the pathological diagnosis of HCC.

Surgical resection for small hepatocellular carcinoma in cirrhosis: the Eastern experience

Detection of small Hepatocarcinoma (HCC) by screening of high-risk populations is important to increase the percentage of patients suitable for curative treatment, which would lead to prolongation of the mean survival of patients with HCC. It should be remembered that small HCC is not always necessarily equivalent to early HCC as defined histologically. With recent advances in diagnostic imaging modalities, including contrast-enhanced ultrasonography and magnetic resonance imaging with liver-specific contrast enhancement, accurate differential diagnosis of early HCCs from dysplastic nodules has become possible. Because a certain proportion of small HCCs is known to show microscopic vascular invasion, surgical resection would be the treatment of first choice. To minimize potential microscopic invasion, anatomic resection and/or resection with a wide margin should be performed, while preserving liver function to the maximum extent possible. Surgical resection, however, cannot prevent multicentric occurrence of HCC, which remains a major issue precluding curative treatment of HCC.

A morpho-molecular prognostic model for hepatocellular carcinoma

Background:

Hepatocellular carcinoma (HCC) is the third common cause of cancer-related deaths and its prognostication is still suboptimal. The aim of this study was to establish a new prognostication algorithm for HCC.

Methods:

In all, 13 biomarkers related to the etiopathogenesis of HCC were evaluated by immunohistochemistry using tissue microarrays containing 121 primary HCC resection cases, and validated in subsequent cohort of 85 HCC cases. The results were compared with Affymetrix Gene Chip Human Genome U133Plus microarray data in a separate cohort of 228 HCC patients.

Results:

On immunohistochemical evaluation and multivariate Cox regression analysis p53, alpha fetaprotein (AFP), CD44 and CD31, tumour size and vascular invasion, were significant predictors for worse survival in HCC patients. A morpho-molecular prognostic model (MMPM) was constructed and it was a significant independent predictor for overall survival (OS) and relapse-free survival (RFS) (P<0.000). The OS and RFS of HCC^low was higher (104 and 78 months) as compared with HCC^high (73 and 43 months) (P<0.0001for OS and RFS). Hepatocellular carcinoma patients with higher stage (III+IV), >5 cm tumour size, positive vascular invasion and satellitosis belonged to HCC^high group. The validation group reproduced the same findings. Gene expression analysis confirmed that 7 of the 12 biomarkers were overexpressed in >50% of tumour samples and significant overexpression in tumour samples was observed in AFP, CD31, CD117 and Ki-67 genes.

Conclusion:

The MMPM, based on the expression of selected proteins and clinicopathological parameters, can be used to classify HCC patients between good vs poor prognosis and high vs low risk of recurrence following hepatic resection.

Radiofrequency ablation of high-grade dysplastic nodules

High-grade dysplastic nodules (HGDNs) are known to be premalignant lesions of hepatocellular carcinoma (HCC). We devised a model to estimate the long-term survival benefit of treating HGDNs by radiofrequency ablation (RFA) (Group I), as compared with regular follow-up and timely treatment by resection (Group II). A hypothetical 60-year-old compensated patient with cirrhosis was assumed. The system being modeled was assumed to be a simple Markov process, and state transition probabilities were given as parameters. Data used for simulation were obtained by a systematic review of the literature. The reported overall malignant transformation rates of HGDNs ranged from 12.5% to 80.8%, and were assumed to be 20%, 50%, and 80% using the best, moderate, and worst scenarios for Group II, respectively. The 5-year overall survival benefit of Group I compared with Group II was calculated by summing the detrimental effect of overtreatment and the beneficial effects of avoiding operative mortality. When the overall malignant transformation rate was set at 20%, 50%, or 80% the expected additional 5-year overall survival benefits of Group I compared with Group II were -0.05%, 0.20%, and 0.47%, respectively, and the corresponding additional 10-year overall survival benefits were 0.03%, 0.33%, and 0.55%, respectively. One-way sensitivity analysis showed that Group I was preferable to Group II in terms of 5-year overall survival when the 5-year overall malignant transformation rate was greater than 25.9%.

CONCLUSION

No definite evidence indicates that the treatment of HGDNs by RFA provides additional long-term overall survival benefit as compared with regular follow-up and timely treatment. The findings of the present study concur with the present American Association for the Study of Liver Diseases guidelines.

Soluble VEGF receptor-2 may be a predictive marker of anti-angiogenic therapy with clinically available safe agents

The identification of biomarkers of anti-angiogenic therapy that predict clinical benefit is of vital importance. We previously reported that a combination treatment with clinically available safe agents, specifically angiotensin-converting enzyme inhibitor (ACE-I) and vitamin K (VK), inhibited the cumulative recurrence of hepatocellular carcinoma (HCC) via suppression of the vascular endothelial growth factor (VEGF). The present study aimed to identify non-invasive biological markers that predict the clinically beneficial effect of this combination regimen. A combination of ACE-I (perindopril; 4 mg/day) and VK (menatetrenone; 45 mg/day) was administered for 54 months following curative therapy for HCC. The cumulative recurrence and several indices, which are reportedly considered as biological markers of anti-angiogenic therapies, were analyzed. The combined treatment of ACE-I and VK markedly inhibited the cumulative recurrence of HCC during the 54-month follow-up. The serum VEGF and soluble VEGF receptor (sVEGFR)-2 were significantly suppressed with this combination regimen, whereas sVEGFR-1 was not. In HCC patients without recurrence, a significant suppression of VEGF and sVEGFR-2 was achieved within 6 and 3 months after treatment, respectively. In conclusion, the combination treatment of ACE-I and VK is a potentially novel anti-angiogenic strategy for secondary chemoprevention against HCC since the two agents are widely used in clinical practice without serious side effects. Furthermore, sVEGFR-2 may become a useful clinical predictive marker of this combination treatment.

Interobserver and intraobserver variability in evaluating vascular invasion in hepatocellular carcinoma

BACKGROUND AND AIM

Hepatocellular carcinoma (HCC) is unique in that the presence of vascular invasion significantly changes tumor stage. Even though searching for vascular invasion is a common practice in surgical pathology, there appears to be a great variation among pathologists in its recognition. This study was designed to assess whether HCC could be accurately staged using vascular invasion as a staging parameter.

METHODS

The interobserver and intraobserver agreement for vascular invasion was analyzed in 126 liver resections for HCC. Selected slides were circulated twice among six pathologists for independent review using their own criteria. One to three representative images from 26 equivocal cases selected by one of the authors were re-evaluated by the pathologists. The presence or absence of vascular invasion on each slide or image was recorded as yes or no. The results were analyzed using unweighted kappa statistic analysis for multiple raters.

RESULTS

The interobserver agreement was moderate on two slide circulations with kappa values of 0.50 (95% confidence interval 0.45-0.55) and 0.43 (0.38-0.47), respectively. The kappa value dropped significantly to 0.19 (0.09-0.29) on selected images photographed from controversial cases. The intraobserver agreement was moderate, with kappa values ranging from 0.23 to 0.56 (mean = 0.45).

CONCLUSIONS

Pathologists can reproducibly recognize vascular invasion in many HCC cases but may have difficulty in equivocal cases, which may lead to either understaging or overstaging of the tumors. This may have a significant impact on prognostic assessment and therapeutic decision making. Our observations indicate the need for improved definition for vascular invasion in HCC.

Attenuation of insulin-resistance-based hepatocarcinogenesis and angiogenesis by combined treatment with branched-chain amino acids and angiotensin-converting enzyme inhibitor in obese diabetic rats

BACKGROUND

Insulin resistance (IR) is reportedly involved in the progression of hepatocellular carcinoma (HCC). Because neovascularization plays an important role in HCC, including hepatocarcinogenesis, an angiostatic therapy would be a promising approach for chemoprevention against HCC. The aim of the present study was to examine the combined effect of clinically used branched-chain amino acids (BCAAs) and an angiotensin-converting enzyme inhibitor (ACE-I), in conjunction with neovascularization, on hepatocarcinogenesis under the condition of IR.

METHODS

The combined effect of the treatment on the development of liver enzyme-altered preneoplastic lesions, angiogenesis, and several indices was elucidated in obese diabetic rats. We also performed several sets of in vitro experiments to examine the mechanisms involved.

RESULTS

When used individually, both BCAAs and ACE-I at clinically comparable low doses significantly attenuated the development of preneoplastic lesions, along with the suppression of both angiogenesis and vascular endothelial growth factor (VEGF) expression. The combination treatment with both agents exerted a more potent inhibitory effect than that of either single agent. Our in vitro study showed a similar combined effect on endothelial cell tubule formation.

CONCLUSION

This combination regimen showed a marked chemopreventive effect against hepatocarcinogenesis, along with suppression of neovascularization and VEGF expression, in obese diabetic rats. Because both BCAAs and ACE-Is are widely used in clinical practice, this combination therapy may represent a potential new strategy for chemoprevention against IR-based HCC in the future.

Identification of proteins differentially expressed between capillary endothelial cells of hepatocellular carcinoma and normal liver in an orthotopic rat tumor model using 2-D DIGE

Hepatocellular carcinoma (HCC) is one of the deadliest cancers with few treatment options. It is a hypervascular tumor in which angiogenesis plays a critical role in its progression. Tumor capillary endothelial cells (TECs) in HCC are known to originate from liver sinusoid endothelial cells, which then go through a capillarization process to become morphologically as well as functionally different TECs. In this work, we investigated proteins differentially expressed between freshly isolated TECs and sinusoid endothelial cells from well-formed rat HCC using 2-D DIGE coupled with MALDI-TOF/TOF MS. Thirty-eight unique proteins were identified to be differentially expressed more than twofold between the two endothelial cell types. Amongst the differentially expressed proteins, two novel endothelial markers, EH domain-containing protein 3 and galectin-3, were confirmed by Western blot and immunohistochemistry in both rat and human HCC samples. We showed that EH domain-containing protein 3 is significantly down-regulated in TECs, but galectin-3 is up-regulated. We propose possible roles of these two proteins in tumor vessel development in HCC.

Combination of vitamin K2 and angiotensin-converting enzyme inhibitor ameliorates cumulative recurrence of hepatocellular carcinoma

BACKGROUND/AIMS

No chemopreventive agent has been approved against hepatocellular carcinoma (HCC) yet. Since neovascularization plays a pivotal role in HCC, an angiostatic agent is considered as one of the promising approaches. The aim of this study was to elucidate the combined effect of the clinically used vitamin K(2) (VK) and angiotensin-converting enzyme inhibitor (ACE-I) on cumulative recurrence after curative treatment on a total of 87 patients, especially in consideration of neovascularization.

METHODS

VK (menatetrenone; 45 mg/day) and/or ACE-I (perindopril; 4 mg/day) were administered for 36-48 months after curative therapy for HCC. The cumulative recurrence and several indices were analyzed.

RESULTS

A 48-month follow-up revealed that the combination treatment with VK and ACE-I markedly inhibited the cumulative recurrence of HCC in association with suppression of the serum level of the vascular endothelial growth factor (VEGF); a central angiogenic factor. The serum level of lectin-reactive alpha-fetoprotein was also suppressed almost in parallel with VEGF. These beneficial effects were not observed with single treatment using VK or ACE-I.

CONCLUSIONS

The combination treatment of VK and ACE-I may suppress the cumulative recurrence of HCC after the curative therapy, at least partly through suppression of the VEGF-mediated neovascularization.

Branched-chain amino acids suppress insulin-resistance-based hepatocarcinogenesis in obese diabetic rats

BACKGROUND

Branched-chain amino acids (BCAAs) reportedly inhibit the incidence of hepatocellular carcinoma (HCC) in patients with liver cirrhosis and obesity that is frequently associated with insulin resistance (IR). However, the possible mechanism is still obscure. The aim of the present study was to examine the effect of BCAAs, especially in conjunction with angiogenesis, on hepatocarcinogenesis under the condition of IR.

METHODS

The effect of BCAAs on the development of liver enzyme-altered preneoplastic lesions and angiogenesis was examined in obese diabetic Otsuka Long-Evans Tokushima Fatty rats. We also performed an in vitro study to elucidate the possible mechanisms involved.

RESULTS

Treatment with BCAAs markedly inhibited glutathione-S-transferase placental form (GST-P)-positive preneoplastic lesions along with suppression of neovascularization in the liver. The hepatic expression of vascular endothelial growth factor (VEGF), a potent angiogenic factor, was also attenuated. BCAA treatment significantly suppressed glucose- and insulin-induced in vitro angiogenesis in the presence of VEGF.

CONCLUSIONS

In obese diabetic rats BCAAs exerted a chemopreventive effect against HCC, associated with the suppression of VEGF expression and hepatic neovascularization. Since BCAA preparations are widely used in clinical practice for patients with chronic liver diseases, this agent may represent a new strategy for chemoprevention against HCC in the future.

Relationship between pattern of tumor enhancement and clinicopathologic characteristics in intrahepatic cholangiocarcinoma

AIM

Common enhancement pattern of intrahepatic cholangiocarcinoma (ICC) on computed tomography (CT) is that of hypovascular enhancement; however, in some cases, tumor shows identical enhancement in the arterial phase to that in hepatocellular carcinoma. To identify the specific characteristics of different enhancement patterns, we examined the relationship between CT enhancement pattern and clinicopathological features or postoperative prognosis.

METHOD

Subjects were 43 consecutive ICC patients who had undergone hepatectomy. Enhancement patterns were divided into two types: hypovascular or delayed enhancement (Type A), and early enhancement in the arterial phase (Type B).

RESULTS

Type A enhancement was observed in 23 patients and Type B in 20. Accompanying chronic viral hepatitis was significantly more frequent in Type B than Type A. Well-differentiated adenocarcinoma was significantly more frequent in Type B than Type A. Multiple tumors were significantly more frequent in Type A than Type B. Japanese TNM stage I and II was more frequent in patients with Type B than those with Type A. Disease-free or overall survival was significantly better in patients with Type B than those with Type A.

CONCLUSION

Early enhancement in the arterial phase might be a useful indicator of lower malignant potential and better survival in ICC patients.

Vascular changes in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most vascular solid tumors, in which angiogenesis plays an important role. The status of angiogenesis in HCC correlates with the disease progression and prognosis, and thus provides a potential therapeutic target. This review summarizes the vascular changes and molecular and cellular basis of angiogenesis in HCC. Development of HCC is characterized by arterialization of its blood supply and sinusoidal capillarization. Vascular endothelial growth factor (VEGF) is a potent angiogenic factor that plays a critical role in mediating angiogenesis in HCC. The VEGF can function on various types of cells, such as endothelial cells, hepatic stellate cells, endothelial progenitor cells and hemangiocytes, to induce vascular changes in HCC. Therefore, blockade of VEGF-mediated pathways, either by anti-VEGF neutralizing antibody or tyrosine kinase inhibitors that target VEGF receptors, suppresses carcinogenesis and angiogenesis in HCC. In addition to VEGF, several other angiogenic factors in HCC have recently been identified. These factors can also regulate angiogenic processes through interaction with VEGF or VEGF-independent pathways. Despite the fact that treatment of HCC remains a tough task due to lack of effective systemic therapy, antiangiogenic therapy has already entered clinical trials in HCC patients and sheds light on a promising novel treatment for this disease.

Early hepatocellular carcinoma: pathology, imaging, and therapy

BACKGROUND

In 1987, Japanese researchers proposed to define the pathological concept of early hepatocellular carcinoma (HCC). However, there are some conceptual differences between the East and the West in the diagnosis and treatment of early HCC.

METHODS

To provide up-to-date data for making a worldwide consensus, this article has collected six papers focused on the management of early HCC, which were presented in the Fifth International Meeting of "Hepatocellular Carcinoma: Eastern and Western Experiences" in Houston in January 2007.

RESULTS

In the pathological perspective, the common criteria to discriminate early HCC from dysplastic nodule included hepatocytic invasion of portal triads and septa (stromal invasion). The current imaging modalities such as contrast-enhanced ultrasound (CEUS), computed tomography (CT), and magnetic resonance imaging (MRI) with the use of intravenous contrast material with multiphasic imaging could enhance their ability to accurately characterize early HCC. From the treatment perspective, a single early HCC had a high chance for cure by resection, ablation, or transplantation, which proved to be the earliest clinical entity (Stage 0 HCC).

CONCLUSIONS

Early HCC is characterized by its incipient malignant nature and by an extremely favorable clinical outcome, thereby justifying its definition.

Analysis of morphological variables and arterialization in the differential diagnosis of hepatic nodules in explanted cirrhotic livers

Background

Many terminologies have been given to dysplastic hepatocellular nodules, which are preneoplastic lesions. In 1995, the International Working Party meeting established the nomenclature and morphological criteria for hepatocellular nodular lesions. Nevertheless, an unequivocal differential diagnosis is sometimes difficult, particularly among large regenerative nodules, dysplastic nodules and hepatocellular carcinoma. Angiogenesis is observed during hepatocarcinogenesis and the presence of the isolated arteries may help to discriminate these nodules. The relevance of the International Working Party histological variables and presence of the isolated arteries were analyzed with regard to the diagnosis of large regenerative nodules, low and high grade dysplastic nodules and hepatocellular carcinoma, in order to evaluate which have a real contribution in such diagnoses.

Methods

One hundred and seven nodular hepatocellular lesions over 5 mm (or smaller nodules with a different color) from explanted cirrhotic livers were analyzed and classified following the criteria of the International Working Party. Classifications were as follows: large regenerative nodules, low grade dysplastic nodules, high grade dysplastic nodules and hepatocellular carcinoma. The presence of isolated arteries (not related to the portal tracts or fibrosis) was verified for the nodules.

Results

Among the 107 nodular lesions studied, 17 were classified as large regenerative nodules, 38 as low grade dysplastic nodules, 28 as high grade dysplastic nodules and 24 as hepatocellular carcinoma. The most relevant International Working Party variables in the differential diagnosis of the nodules were cellularity, trabeculae thickness, cytoplasmic staining, nuclear atypia, pseudoacinar pattern, portal tracts, nucleocytoplasmic ratio and mitosis. The isolated arteries, identified by hematoxylin and eosin staining, were important discriminating between two groups: low grade lesions (large regenerative nodules/low grade dysplastic nodules) and high grade lesions (high grade dysplastic nodules/hepatocellular carcinoma) (P < 0.001).

Conclusion

The International Working Party criteria allow for the classification of the majority of hepatocellular nodules. However, other features such as cytoplasmatic tintorial affinity and pseudoacinar pattern may contribute to these diagnoses. The finding of isolated arteries in a nodular lesion should be investigated carefully, since the nodule could be a dysplastic lesion or hepatocellular carcinoma.

From molecular biology to targeted therapies for hepatocellular carcinoma: the future is now

Hepatocellular carcinoma (HCC) is characterized as a highly chemoresistant cancer with no effective systemic therapy. Despite surgical or locoregional therapies, prognosis remains poor because of high tumor recurrence or tumor progression, and currently there are no well-established effective adjuvant therapies. The molecular biology of carcinogenesis and tumor progression of HCC has been increasingly understood with intense research in recent years. Several important intracellular signaling pathways such as the Ras/Raf/Mek/Erk pathway and PI3k/Akt/mTOR pathway have been recognized, and the role of several growth factors and angiogenic factors such as EGF and VEGF has been confirmed. Effective agents targeting these molecular abnormalities have been developed and widely tested in preclinical studies of HCC cell lines or xenograft models. Several agents have entered clinical trials in HCC patients, and recent data indicated that a multikinase inhibitor targeting Ras kinase and VEGFR-2, sorafenib, is effective in prolonging survival of patients with advanced HCC. The management of advanced HCC is entering the era of molecular targeting therapy, which is of particular significance for HCC in view of the lack of existing effective systemic therapy for this cancer.

Silencing SMYD3 in hepatoma demethylates RIZI promoter induces apoptosis and inhibits cell proliferation and migration

AIM: To investigate the role of SMYD3 in hepatocellular carcinoma (HCC) development and progression and to verify whether its regulation activity was through RIZ1 inactivation.

METHODS: Expression of SMYD3 in HCC cell lines and tissues were measured; silencing of SMYD3 by RNA interference (RNAi) was effectuated, hepatoma cell proliferation, migration and apoptosis were tested, with RIZ1 CpG promoter methylation, and corresponding mRNA expression were investigated.

RESULTS: SMYD3 over-expression in HCC was associated with RIZ1 hypermethylation and mRNA down-expression. Suppression of SMYD3 expression de-methylated RIZ1 CpG promoter (P < 0.01) and increased RIZ1 mRNA expression (P < 0.01). Consequently, SMYD3 down-expression with RIZ1 de-methylation strongly inhibited hepatoma cell growth (MTT inhibitory rates: Pgenesil-1-s1 60.95% ± 7.97%, Pgenesil-1-s2 72.14% ± 9.68% vs Pgenesil-1-hk 6.89% ± 4.12%, P < 0.01) and migration (Pgenesil-1-s1 4.24% ± 1.58%, Pgenesil-1-s1 4.87% ± 0.73% vs Pgenesil-1 19.03% ± 4.63%, Pgenesil-1-hk 19.95% ± 5.21%, P < 0.01) and induced apoptosis (FCM subG1 phase Pgenesil-1-s1 19.07% ± 1.78%, Pgenesil-1-s2 17.68% ± 2.36% vs Pgenesil-1 0.47% ± 0.12%, Pgenesil-1-hk 1.46% ± 0.28%, P < 0.01. TUNEL-positive cells: Pgenesil-1-s1 40.24% ± 5.18%, Pgenesil-1-s2 38.48% ± 4.65% vs Pgenesil-1 2.18% ± 1.34%, Pgenesil-1-hk 2.84% ± 1.22%, P < 0.01) in HepG2 cells.

CONCLUSION: These results demonstrate that SMYD3 plays a critical role in the carcinogenesis and progression of HCC. The proliferation, migration induction and apoptosis inhibition activities of SMYD3 may be mediated through RIZ1 CpG promoter hypermethylation.

Enhancement patterns and signal-intensity characteristics of small hepatocellular carcinoma in cirrhosis: pathologic basis and diagnostic challenges

Recent pathologic studies of hepatic resection and transplantation specimens have elucidated the morphologic features of the precancerous lesions and small hepatocellular carcinomas (HCCs) arising in cirrhotic livers. Small HCCs measuring less than 2 cm in diameter are of two types: vaguely nodular, well-differentiated tumors, also known as "early" HCCs, and distinctly nodular tumors, with histologic features of "classic" HCC. The precancerous lesions include dysplastic foci and dysplastic nodules. "Classic" small HCCs are supplied by nontriadal arteries, whereas early HCCs and dysplastic nodules may receive blood supply from both portal tracts and nontriadal arteries. The similarities in blood supply of these three types of nodular lesions result in significant overlap of findings on dynamic imaging. Nevertheless, small HCCs sometimes display characteristic radiologic features, such as "nodule-in-nodule" configuration and "corona enhancement" pattern. Moreover, various histologic features of these nodular lesions may also be related to a variety of signal intensities and attenuation coefficients, while the presence of cirrhosis is known to limit the sensitivity and specificity of any imaging modality, due to liver inhomogeneity. Because of these reasons, imaging findings of nodular lesions in cirrhotic livers are often inconclusive, emphasizing the need for a better understanding of these imaging features.

Combined treatment of vitamin K2 and angiotensin-converting enzyme inhibitor ameliorates hepatic dysplastic nodule in a patient with liver cirrhosis

Although it is well known that the hepatocellular carcinoma (HCC) is an ominous complication in patients with liver cirrhosis, there has been no approved drug to prevent the development of HCC to date. We previously reported that the combined treatment of vitamin K₂ (VK) and angiotensin-converting enzyme inhibitor (ACE-I) significantly suppressed the experimental hepatocarcinogenesis. A 66-year-old Japanese woman with hepatitis C virus (HCV)-related liver cirrhosis developed a dysplastic nodule in the liver detected by enhanced computed tomography along with elevation of the tumor markers, namely, alpha-fetoprotein (AFP) and lectin-reactive demarcation (AFP-L3), suggesting the presence of latent HCC. After oral administration of VK and ACE-I, the serum levels of both AFP and AFP-L3 gradually decreased without any marked alteration of the serum aminotransferase activity. After one-year treatment, not only the serum levels of AFP and AFP-L3 returned to the normal ranges, but also the dysplastic nodule disappeared. Since both VK and ACE-I are widely used without serious side effects, this combined regimen may become a new strategy for chemoprevention against HCC.

Immunocytochemical diagnosis of hepatocellular carcinoma and identification of carcinomas of unknown primary metastatic to the liver on fine-needle aspiration cytologies

BACKGROUND

Difficulties with cytologic diagnoses on fine-needle aspiration cytology (FNAC) of the liver can be overcome by the application of immunocytochemical panels applied on smears. The aim of the current study was to analyze the performance of a panel of monoclonal antibodies to differentiate hepatocellular carcinoma (HCC) from metastatic carcinoma (MC) or regenerative nodules, and to identify the to date unknown primary sites of carcinomas that had metastasized to the liver.

METHODS

In a validating cohort study, 108 FNACs coin lesions in the liver were routinely evaluated applying immunocytochemistry as an ancillary method. All patients had confirmatory histologic and/or clinical follow-up. A total of 23 HCCs were analyzed for the distinction from MC or regenerative nodules applying a panel of HepPar1, alpha-fetoprotein, BerEP4, CD31, CD68, and Ki-67. A total of 85 cases of unknown primary tumor metastatic to the liver were used to identify the tumor sites applying a panel of CK5/6, CK7, CK20, CA 125, thyroid transcription factor-1 (TTF-1), and Cdx2.

RESULTS

Typing accuracy to differentiate HCC from MC or regenerative nodules was 100% and 90.3%, respectively, to identify the primary tumor site of MC. In 23 cases, the site of the primary tumor remained clinically unknown.

CONCLUSIONS

The application of immunocytochemical panels on the same slide used for microscopic diagnosis is a useful tool in the routine assessment of FNACs of the liver to discriminate HCCs from MC or regenerative nodules and for the identification of primary sites of MC. Their performance should be confirmed in a larger series of cases.

Expression of vascular endothelial-cadherin in human hepatocellular carcinoma tissues

AIM

Angiogenesis is important in tumor growth and progression to metastasis. Vascular endothelial (VE)-cadherin is an endothelial cell-specific cadherin required for angiogenesis, but its expression in hepatocellular carcinoma (HCC) tissues has not been examined.

METHODS

Expression of VE-cadherin was analyzed in 31 HCC frozen tissue specimens by immunohistochemical and immunoelectron microscopic procedures. In addition, the association of its expression with clinicopathological parameters was investigated to determine the possible diagnostic or predictive value of VE-cadherin expression in neoplastic and non-neoplastic liver lesions.

RESULTS

Immunoreactive VE-cadherin expression was faint or barely detectable on sinusoidal endothelial cells of normal liver but was evident on sinusoidal or capillary endothelium of chronic hepatitis, cirrhosis, and HCC tissues. VE-cadherin expression was more intense on capillary endothelium of HCC tissues in 26 (84%) of 31 patients than on sinusoidal endothelium of surrounding non-tumorous liver tissues with chronic liver diseases. The intensity or intracapillary extent of positive stain for VE-cadherin on capillary endothelium of HCC tissues was significantly associated with tumor size, capsular invasion and tumor cell differentiation in HCC.

CONCLUSIONS

Intense VE-cadherin expression was evident in capillary endothelium of HCC tissues, giving the first indication of association with clinicopathological features of HCC patients.

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.

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Targeted deletion of FATP5 reveals multiple functions in liver metabolism: alterations in hepatic lipid homeostasis

BACKGROUND & AIMS

Fatty acid transport protein 5 (FATP5/Slc27a5) has been shown to be a multifunctional protein that in vitro increases both uptake of fluorescently labeled long-chain fatty acid (LCFA) analogues and bile acid/coenzyme A ligase activity on overexpression. The aim of this study was to further investigate the diverse roles of FATP5 in vivo.

METHODS

We studied FATP5 expression and localization in liver of C57BL/6 mice in detail. Furthermore, we created a FATP5 knockout mouse model and characterized changes in hepatic lipid metabolism (this report) and bile metabolism (the accompanying report by Hubbard et al).

RESULTS

FATP5 is exclusively expressed by the liver and localized to the basal plasma membrane of hepatocytes, congruent with a role in LCFA uptake from the circulation. Overexpression of FATP5 in mammalian cells increased the uptake of 14C-oleate. Conversely, FATP5 deletion significantly reduced LCFA uptake by hepatocytes isolated from FATP5 knockout animals. Moreover, FATP5 deletion resulted in lower hepatic triglyceride and free fatty acid content despite increased expression of fatty acid synthetase and also caused a redistribution of lipids from liver to other LCFA-metabolizing tissues. Detailed analysis of the hepatic lipom of FATP5 knockout livers showed quantitative and qualitative alterations in line with a decreased uptake of dietary LCFAs and increased de novo synthesis.

CONCLUSIONS

Our findings support the hypothesis that efficient hepatocellular uptake of LCFAs, and thus liver lipid homeostasis in general, is largely a protein-mediated process requiring FATP5. These new insights into the physiological role of FATP5 should lead to an improved understanding of liver function and disease.

Angiogenesis and antiangiogenic therapy in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a hypervascular tumor characterized by neovascularization, which plays an important role in the growth and progression of HCC. Angiogenesis provides a target for novel prognostic and therapeutic approaches to HCC. Assessment of microvessel density using immunohistochemical staining for specific endothelial cell markers such as CD34 has been shown to provide prognostic information independent of conventional pathological parameters in HCC patients. Recent studies have unveiled the important angiogenic factors involved in the regulation of angiogenesis in HCC, although the exact molecular pathways are far from clear. Current data suggest that vascular endothelial growth factor (VEGF) plays a critical role in angiogenesis of HCC. Tumor expression of VEGF has been shown to correlate with tumor invasiveness and prognosis in patients with HCC. VEGF is an important molecular target for antiangiogenic therapy. Studies in animal models have demonstrated the efficacy of antiangiogenic agents such as anti-VEGF antibody and antagonists of VEGF receptors in suppressing hepatocarcinogenesis and growth of HCC. Antiangiogenic therapy has already entered clinical trials in HCC patients and holds the promise of providing an effective novel treatment for HCC, which is of great clinical significance because there is no existing effective systemic therapy for HCC.

Potential prognostic value of leptin receptor in hepatocellular carcinoma

BACKGROUND

Obesity is associated with several human malignancies, including hepatocellular carcinoma (HCC). This association may result from the deregulated expression of adipokines.

AIMS

To explore the potential role and the prognostic value of leptin receptor (Ob-R) in HCC.

METHODS

66 patients with pathologically confirmed HCC were included in this study. Immunohistochemistry was used to evaluate the expression of Ob-R, microvessel density (MVD) and Ki-67 index in these patients. Eventually, the profiles of Ob-R expression, obtained by a semiquantitative scoring system, were further correlated with Ki-67 expression, intratumour MVD, clinicopathological characteristics and overall survival.

RESULTS

High Ob-R expression was seen in 53% of patients with HCC and was significantly correlated with intratumour MVD (high v low; 59.4 (3.2) v 44.7 (3.7); p = 0.004), but not with Ki-67 expression. In addition, Ob-R expression was inversely correlated with vascular invasion (p = 0.037), but not with other known clinicopathological characteristics. The Kaplan-Meier survival curve showed that high Ob-R expression was associated with a better overall survival (p = 0.027). Meanwhile, multivariate analysis showed that Ob-R expression was a significant determinant for HCC (odds ratio 0.02, 95% confidence interval 0.01 to 0.85; p = 0.041).

CONCLUSION

Ob-R expression may have a potential role in the carcinogenesis of HCC. The positive association of Ob-R expression in the cancerous lesions of HCC with the survival outcome can be explained by its inverse correlation with vascular invasion, and may have prognostic value in HCC.

Combination of vitamin K2 and the angiotensin-converting enzyme inhibitor, perindopril, attenuates the liver enzyme-altered preneoplastic lesions in rats via angiogenesis suppression

BACKGROUND/AIMS

Chemoprevention should be a promising approach to improve the prognosis of the patients with hepatocellular carcinoma (HCC). Angiogenesis is now recognized as a crucial step not only in tumor growth, but also in early carcinogenesis. The aim of this study was to elucidate the combination effect of the clinically used vitamin K(2) (VK) and the angiotensin-converting enzyme inhibitor, perindopril (PE), on hepatocarcinogenesis, especially in conjunction with angiogenesis.

METHODS

In a diethylnitrosamine-induced rat hepatocarcinogenesis model, the effects of VK and PE on the development of liver enzyme-altered preneoplastic lesions and angiogenesis were examined.

RESULTS

Treatment with both VK and PE markedly inhibited the development of preneoplastic lesions in association with suppression of neovascularization in the liver. The combination treatment with VK and PE exerted a more potent inhibitory effect as compared with the single agent treatments. The in vitro study demonstrated that VK and PE inhibited the endothelial cell (EC) tubular formation. VK also suppressed the EC proliferation in a dose-dependent manner.

CONCLUSIONS

The combination of VK and PE exerted a chemopreventive effect against rat liver carcinogenesis via suppression of angiogenesis. Since both agents are widely used in the clinical practice, this combination therapy may represent a potential new strategy for chemoprevention against HCC in the future.

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.

Microvessel density of malignant and benign hepatic lesions and MRI evaluation

AIM: To study the difference of microvessel density (MVD) between malignant and benign hepatic lesions and study the relationship between MVD and dynamic enhanced magnetic resonance imaging (MRI) for evaluation of microvessels within malignant and benign hepatic lesions.

METHODS: A total of 265 specimens of hepatocellular carcinoma (HCC), 122 cirrhosis tissues and 22 hepatic benign lesions were enrolled for MVD by immunohistochemistry on tissue microarray, of which 49 underwent MRI examination before surgery, then contrast-to-noise ratios (CNR) and enhancement index (EI) in all the phases were calculated. Pearson correlation was performed for correlation analysis between CNR, EI and MVD.

RESULTS: MVD of HCC was 22.7 ± 15.8 (mean ± SD), which was obviously higher than that of cirrhosis tissue (8.3 ± 7.6, P < 0.01), but was not statistically different from that of benign lesions (31.3 ± 22.7, P>0.05). Among HCC, MVD of gradesI-II was 29.9 ± 18.6, which was much higher than those of grade III (22.2 ± 18.2, P < 0.01) and gradeIV (22.9 ± 19.0, P < 0.01). MVD of HCC (P = 0.018) and of benign lesions (P = 0.014) were both correlative with CNR in arterial phase.

CONCLUSION: Neoangiogenesis is an important feature for malignant tumor, and MVD may act as a biological marker in differentiating malignant from benign hepatic lesions. Dynamic enhanced MRI, especially image in arterial phase, may act as an MVD evaluation criterion for malignant and benign hepatic lesions.

Halting the interaction between vascular endothelial growth factor and its receptors attenuates liver carcinogenesis in mice

It has been shown that angiogenesis plays an important role not only in tumor growth, but also in early carcinogenesis. The expression of a potent angiogenic factor, vascular endothelial growth factor (VEGF), increased during the early stage of carcinogenesis. In this study, the effects of the neutralizing monoclonal antibodies R1 mAb and R2 mAb of the VEGF receptors Flt-1 (VEGFR-1) and KDR/Flk-1 (VEGFR-2), respectively, on murine hepatocarcinogenesis induced by diethylnitrosamine (DEN) were examined. The effects of R1 mAb and R2 mAb on spontaneous lung metastasis from hepatocellular carcinoma (HCC) were also investigated. VEGF expression and neovascularization in the tumor increased stepwise during hepatocarcinogenesis. Treatment with both R1 mAb and R2 mAb markedly inhibited the development of HCC and adenoma in the liver. The inhibitory effect of R2 mAb was more potent than that of R1 mAb, and the combination treatment with both mAbs almost completely attenuated hepatocarcinogenesis. Both R1 mAb and R2 mAb treatment significantly suppressed the development of angiogenesis in HCC. The suppressive effects against angiogenesis R1 mAb and R2 mAb were similar in magnitude to their inhibitory effects against hepatocarcinogenesis. Furthermore, spontaneous lung metastasis from HCC was also significantly suppressed by R1 mAb and R2 mAb treatment. In conclusion, these results suggest that VEGF and receptor interaction plays an important role in hepatocarcinogenesis and in spontaneous lung metastasis from HCC.