Nucleolar organizer regions (NORs) in normal and pathological liver: a quantitative analysis

By means of a silver staining method, Nucleolar Organizer Region-associated proteins (NORs) have been evaluated on paraffin sections of a series of 58 ultrasound-guided liver biopsy specimens. These included 12 normal livers, 12 cirrhotic livers, 12 cases of chronic hepatitis and 22 cases of hepatocellular carcinoma. A significant difference (P less than 0.001) was found between the mean AgNOR scores of the normal and pathological biopsies, and between the non-neoplastic and the carcinomatous lesions. The authors suggest that AgNOR counts, in combination with conventional histocytological criteria, may be a useful method in the diagnosis of liver diseases.     

Assessment of nucleolar organizer regions (NORs) in proliferative conditions of the liver.

To overcome the diagnostic dilemma in proliferative conditions of the liver which sometimes pose a problem to the working pathologist especially when the material is inadequate, a special staining technique (AgNOR) has been applied. By using this technique, nucleolar organizer regions were counted which determine the proliferative status of the cells. This prospective study included 65 cases of randomly selected liver core and fine needle aspiration biopsies. AgNOR staining was performed on formalin-fixed, paraffin-embedded tissue sections NOR dots were counted in 100 randomly selected hepatocytes at x100 oil immersion objective, and the mean count per cell was calculated for each case. Statistical analysis was done by using the Mann Whitney U test. AgNOR count results were later compared with the histologic diagnosis. The study revealed a gradual increase in mean AgNOR counts from normal liver through cirrhosis to hepatocellular carcinoma. The difference in NOR counts was significant in these three groups. The hepatocellular carcinomas were graded according to the Edmondson-Steiner histological grading system. The Grade I hepatocellular carcinomas show AgNOR counts ranging between 5-6/cell, a score which is much higher than in the normal liver, where it ranges between 1.2-2.0/cell. This technique can be used to assess the lesions where the distinction between normal liver and Grade I hepatocellular carcinoma is difficult with the use of routine methods. AgNOR counts in normal liver and chronic hepatitis cases were insignificant, but there was an appreciable difference between cases of chronic hepatitis, cirrhosis and hepatocellular carcinoma. In view of the results of this study, the AgNOR staining method is found to be a useful diagnostic tool to differentiate between normal liver, cirrhosis and hepatocellular carcinoma and also to precisely discriminate between cases of normal liver and Grade I hepatocellular carcinoma.     

AgNOR counts are not altered in alcoholic cirrhosis

One hundred and two liver biopsy specimens were stained for Argyrophilic nucleolar organizer regions and associated proteins to assess its utility in differentiating normal, cirrhotic and neoplastic liver tissue. A statistically significant (p < 0.001) difference was observed between mean AgNOR counts of normal (1.53 +/- 0.4), post-hepatitic cirrhosis (3.65 +/- 0.53) and hepatocellular carcinoma (7.94 +/- 1.18). In contrast the mean AgNOR count of biopsies with alcoholic cirrhosis (1.57 +/- 0.06) was significantly less (p < 0.001) than post-hepatitic cirrhosis and was similar to that of normal liver tissue. It is concluded that AgNORs can act as a good adjuvant to histology in diagnosing liver diseases especially in differentiating post-hepatitic and alcoholic cirrhosis.     

p53 immunoreactivity in hepatocellular adenoma, focal nodular hyperplasia, cirrhosis and hepatocellular carcinoma

The prolonged half-life of mutant p53 makes feasible its immunocytochemical detection. In order to assess the pathogenetic role of mutant p53 in regenerative and neoplastc liver disease we studied its immunohistochemical expression in cases of hepatic cirrhosis, hepatocellular carcinoma (HCC), cirrhosis with areas of HCC, hepatocellular adenoma and focal nodular hyperplasia. The study included needle and wedge biopsies of 50 cirrhotic livers, 59 HCCs (36 of them with associated cirrhosis), six adenomas and two focal nodular hyperplasias. Sixty-five HCC fineneedle cytology specimens were also included in the study. There was no immunohistochemical evidence of mutant p53 expression in any of the cases of cirrhotic liver (except for one instance associated with HCC) adenoma or focal nodular hyperplasia. In contrast p53 was detected in 8.5% of HCC cases in the biopsy series and 24% of HCC cases in the fine needle aspiration series. In addition, mutant p53 expression in HCC was positively correlated with tumour grade. According to grade, the distribution of p53 positive immunoreactivity among HCCs was as follows: Grade I-II, 0% of cases in the biopsy series and 9% in the fine needle aspirates; Grade III, 18% in the biopsy series and 55% in the fine needle aspirates; and Grade IV, 40% in the biopsy series. Therefore, mutant p53 expression does not seem to be associated with benign liver lesions but seems to correlate with the progression of HCC through various grades of increasing malignancy.     

Is high AgNOR quantity in hepatocytes associated with increased risk of hepatocellular carcinoma in chronic liver disease?

AIMS--To evaluate whether high numbers of silver staining nucleolar organiser regions (AgNORs) in hepatocytes are associated with increased risk of hepatocellular carcinoma in chronic liver disease. METHODS--The quantitative distribution of AgNORs was studied in the liver biopsy specimens of 33 patients with chronic liver disease, 11 of whom developed hepatocellular carcinoma. The interval between liver biopsy and diagnosis of hepatocellular carcinoma was 26 months (range one to 61 months); the mean follow up of patients without hepatocellular carcinoma was 45 months (range 24-59 months). Quantitative evaluation of AgNORs was carried out on silver stained routine sections by morphometric analysis, using a computer assisted image analysis system. RESULTS--High interphase AgNOR values (> 3 microns2) were found in hepatocytes of nine out of the 11 (82%) patients in whom neoplastic transformation occurred. Of the remaining 22 patients, only seven (31%) had AgNOR values higher than > 3 microns2 (chi 2 4.83; p = 0.036). CONCLUSIONS--These results indicate that high numbers of interphase AgNORs are associated with increased risk of hepatocellular carcinoma in patients with chronic liver disease.     

Expression of ABH blood group antigens, receptors of Ulex europaeus agglutinin I, and factor VIII-related antigen on sinusoidal endothelial cells in adenomatous hyperplasia in human cirrhotic livers.

Adenomatous hyperplasia, a hyperplastic parenchymal nodule in the cirrhotic liver, has been presumed to be a preneoplastic lesion in human hepatocarcinogenesis. In this study, phenotypes of the sinusoidal endothelium were examined in adenomatous hyperplasia, hepatocellular carcinoma, cirrhosis, chronic active hepatitis, and normal livers. Adenomatous hyperplasia (n = 74) was histologically classified into two types: ordinary (n = 35) and atypical (n = 39). While the former lacked hepatocellular atypia, the latter consisted of atypical hepatocytes equivocal as to benignity and malignancy, in some of which overt malignant foci were found. The expression of A, B, and H blood group antigens, receptors of Ulex europaeus agglutinin I, and factor VIII-related antigen on the sinusoidal endothelium was minimal or nil in normal livers. It was mild and focal in chronic active hepatitis, cirrhosis, and ordinary adenomatous hyperplasia, while expression was moderate in atypical adenomatous hyperplasia with or without malignant foci, and severe in malignant foci in atypical adenomatous hyperplasia and in hepatocellular carcinoma. These data suggest that phenotypes of the sinusoidal endothelium of atypical adenomatous hyperplasia are closely related to the development of hepatocellular carcinoma, and phenotypic changes of the sinusoidal endothelium occur stepwise corresponding to various stages of hepatocarcinogenesis in cirrhotic livers.     

Looking for large-cell dysplasia in liver needle biopsies how and why?

Liver large cell dysplasia (LCD) is identifiable only at the microscopic level as foci of large hepatocytes with pleomorphic hyperchromatic nuclei and prominent nucleoli. LCD is mainly observed in cirrhotic livers, on surgical specimens, within macroregenerative nodules or low grade dysplastic nodules but also on liver needle biopsies. For needle biopsies, the prevalence of LCD ranges between 15% and 20%. in case of associated hepatocellular carcinoma, the prevalence is around 40%. LCD is more frequent in hepatitis B virus-induced liver cirrhosis than in cirrhosis related to other causes. Two prospective studies showed that LCD is a predictive factor for the occurrence of hepatocellular carcinoma in cirrhotic patients. Nevertheless LCD is probably not a precancerous lesion; dysplastic hepatocytes are biologically senescent polyploid cells unable to carry out normal cell division. Diagnosis of LCD on liver needle biopsy is indicative for the presence of large and numerous foci of LCD within the whole parenchya and allows consequently to select cirrhosis associated with advanced liver cell secescence, i.e. cirrhosis in which multistep genetic alterations of liver cell carcinogenesis could have happened with the greatest probability. Therefore pathologists have to identify and indicate the presence of LCD in the reports of liver needle biopsies     

Argyrophilic nucleolar organizer regions and alpha-fetoprotein in adenomatous hyperplasia in human cirrhotic livers.

Recently, adenomatous hyperplasia (AH) of the liver has been suspected as a precancerous lesion in human hepatocarcinogenesis. The authors examined 75 cases of AH from 42 cirrhotic livers, using staining of argyrophilic nucleolar organizer regions (AgNORs). These reflect proliferative cell activity. Findings in AH were compared with those seen in hepatocellular carcinoma (HCC) and other chronic liver diseases. Expression of alpha-fetoprotein (AFP) was also examined immunohistochemically. The authors classified AH into three types: ordinary (OAH), atypical (AAH), and AH with focal malignancy (FM). OAH implies a lack of atypia; AAH represents AH with structural and cellular atypia but without the features of overt carcinoma; and FM denotes AH with foci of overt HCC. Forty of the 75 cases of AH were categorized as OAH, 19 as AAH, and 16 as FM. The noncancerous areas of FM had features of AAH. The mean number of AgNORs in AH was intermediate between that seen in cirrhosis (2.93) and HCC (6.18) and showed a step-wise increase in the following order: OAH (2.95), AAH (3.89), noncancerous areas in FM (4.58), and malignant foci in FM (5.71). There was no significant difference in AgNOR counts between OAH and cirrhosis. AgNOR counts in AAH and FM were significantly higher than those of OAH, and lower than those of HCC. AFP was positive in 12 of 25 HCCs and in malignant foci of 3 FM lesions, but it was absent in OAH and AAH. These data suggest that OAH has a limited capacity for proliferation but that AAH and FM are much more replicative. The latter two conditions are probably preneoplastic lesions or early forms of HCC.     

Immunolocalization of Cellular Fibronectins in the Normal Liver, Cirrhosis, and Hepatocellular Carcinoma

Cellular (c) fibronectins (Fn) differ biochemically, immunologically, and functionally from plasma fibronectins (pFn). Most existing data on Fn distribution in the normal and diseased liver require revision because those studies were based on reagents that did not distinguish pFn from cFn and predated the development of specific cFn monoclonal antibodies (Mabs). We immunostained cryosections of normal adult livers (n = 5), cirrhotic livers (n = 20), and livers with hepatocellular carcinoma (HCC) (n = 10) by the avidin-biotin-complex method with specific Mabs to the extradomains A and B (EDA, EDB) and oncofetal (One) isoforms of cFn. Selected samples were stained with an antiserum to pFn; fetal livers served as controls. Normal and cirrhotic livers showed EDA-cFn staining in the portal, septal, and perisinusoidal matrix; its distribution was more restricted than that of pFn. In cirrhosis, EDA-cFn reactions were strongest at sites of piecemeal necrosis and around proliferating ductules in biliary cirrhosis. EDA-cFn reactions were consistently most intense in the matrix of HCC. Distinct from adult normal and cirrhotic livers, reactions for EDB-and Onc-cFn were noted exclusively in most cases of HCC. We conclude that the only cFn isoform indigenous to the normal adult liver matrix is EDA-cFn. Enhanced EDA-cFn in cirrhotic livers may serve as indicator of active stromal remodeling. The restriction of EDB-and Onc-cFn to a large subset of HCC and the putative role of cFn in modulating cell-matrix adhesive interactions would suggest that the emergence of these molecules may be related to the variably invasive and metastatic properties of these tumors.     

Hepatic mass lesions: challenges and pitfalls

Though commonly encountered in clinical practice, hepatic mass lesions can present myriad diagnostic challenges, especially in needle biopsy specimens. Familiarity with the various pitfalls and caveats of morphologic evaluation and ancillary staining will likely improve both diagnostic accuracy and clinical outcomes. Herein, we discuss common hepatic mass lesions, including focal nodular hyperplasia, hepatic adenoma (and subtypes), variants of hepatocellular carcinoma, cirrhotic nodules (regenerative and dysplastic), segmental atrophy of the liver, and selected biliary lesions often seen in biopsy and resection specimens.     

Value of glypican 3 immunostaining in the diagnosis of hepatocellular carcinoma on needle biopsy

The diagnostic value of glypican 3 (GPC3) immunostaining on needle biopsy specimens has not been well assessed. In this study, 120 liver needle biopsy specimens, including 46 from cirrhotic livers and 74 hepatocellular carcinomas (HCCs), were immunohistochemically examined for expression of GPC3. The results showed strong cytoplasmic and membranous staining in 36 HCCs (49%), among which 20 cases (56%) showed diffuse immunoreactivity. None of the 46 cirrhotic livers exhibited positive GPC3 immunostaining. The nonneoplastic liver tissues (cirrhotic or noncirrhotic) that were present in the majority of the HCC cases were also completely negative for GPC3 expression. These data demonstrate that GPC3 is a reliable immunohistochemical marker for the diagnosis of HCC on needle biopsy specimens when positive. However, the detection rate in our series seems lower than that reported in studies using resection specimens as the study materials. Our findings emphasize that GPC3 immunoreactivity can be focal and that negative staining should not be viewed as evidence to exclude the diagnosis of HCC in challenging needle biopsy specimens.     

Distribution of constitutive (COX-1) and inducible (COX-2) cyclooxygenase in postviral human liver cirrhosis: a possible role for COX-2 in the pathogenesis of liver cirrhosis

AIMS: Prostaglandins produced by the action of cyclooxygenases (COX) are important mediators of systemic vasodilatation and inflammation in liver cirrhosis. The aim of this study was to investigate the distribution of COX-1 and COX-2 in postviral cirrhosis. METHODS: The immunohistochemical expression of the constitutive (COX-1) and the inducible (COX-2) isoenzymes was investigated in 15 patients with cirrhosis after hepatitis B and C infection; three normal control livers were also analysed. RESULTS: COX-2 was absent from normal liver but was highly expressed in cirrhosis, mainly in the inflammatory, sinusoidal, vascular endothelial, and biliary epithelial cells. Low amounts of COX-1 were expressed in both normal and cirrhotic livers, exclusively in sinusoidal and vascular endothelial cells, with no differences seen between normal and cirrhotic livers. CONCLUSIONS: COX-2 is overexpressed in liver cirrhosis, and possibly contributes to prostaglandin overproduction, which may be a major component of the inflammation and hyperdynamic circulation associated with cirrhosis. Because COX-2 is thought to contribute to tumour development, high COX-2 production could be a contributor to hepatocellular carcinoma development in cirrhosis. The finding of COX-2 and not COX-1 upregulation in cirrhosis could provide a possible new role for selective COX-2 inhibitors in reducing inflammation and minimising the occurrence of hepatocellular carcinoma in patients with cirrhosis.     

Myofibroblasts in hepatitis B related cirrhosis and hepatocellular carcinoma.

Peritoneal liver biopsy specimens from eight patients with hepatitis B associated cirrhosis, complicated by hepatocellular carcinoma, were studied for identification and localisation of myofibroblasts. The avidin-biotin peroxidase complex technique was used on paraffin wax sections, using monoclonal antibodies for actin and desmin, and ultrastructural examination was performed. Myofibroblasts were found in seven of the eight cirrhotic specimens and in all eight tumour specimens. They were identified in the fibrotic areas by the immunohistochemical technique, but ultrastructural examination disclosed their presence in the perisinusoidal space and between tumour cells.     

HGF, MET, and matrix-related proteases in hepatocellular carcinoma, fibrolamellar variant, cirrhotic and normal liver.

Fibrolamellar variant is an uncommon subcategory of hepatocellular carcinoma with a better prognostic outcome. Proteinases and growth factors that are involved in the remodeling of extracellular matrix may influence the behavior of cancers. To determine whether these factors contribute to the distinct etiologies of fibrolamellar hepatocellular carcinoma and traditional hepatocellular carcinoma, we assayed hepatocyte growth factor, the hepatocyte growth factor receptor, and two hepatocyte growth factor activators, hepatocyte growth factor activator and urokinase-type plasminogen activator, in hepatocellular carcinoma, fibrolamellar hepatocellular carcinoma, cirrhotic liver and normal liver. In addition, we examined the urokinase-type plasminogen activator receptor, the type 1 plasminogen activator inhibitor, plasmin, fibrinogen, and the type IV matrix metalloproteinases. Eighteen hepatocellular carcinomas and 11 fibrolamellar hepatocellular carcinomas were obtained as paraffin embedded sections from the University of Pittsburgh Department of Pathology. Frozen tissues from a subset of cases (9 hepatocellular carcinomas, 4 fibrolamellar hepatocellular carcinomas, 12 cirrhotic livers and 2 normal livers) were also available for analysis. Antibodies against urokinase-type plasminogen activator, urokinase-type plasminogen activator receptor, hepatocyte growth factor and hepatocyte growth factor receptor were used to analyze immunoperoxidase stained slides from the paraffin blocks. Western blot analyses using antibodies against hepatocyte growth factor, hepatocyte growth factor receptor, phosphotyrosine, hepatocyte growth factor activator, urokinase-type plasminogen activator receptor, urokinase-type plasminogen activator, plasminogen activator inhibitor-1, fibrinogen and plasmin were performed on membrane-enriched fractions from the frozen tissue, as was collagen zymography for matrix metalloproteinase-2 and matrix metalloproteinase-9. The most notable findings are as follows: hepatocyte growth factor activator was only detected in malignant tissue but not cirrhotic liver or normal liver. Although hepatocyte growth factor was detected in most samples, it was significantly elevated in 5/9 hepatocellular carcinomas. Furthermore, 8/9 fibrolamellar hepatocellular carcinomas demonstrated hepatocyte growth factor receptor levels similar to normal, whereas 8/9 hepatocellular carcinomas and 11/12 cirrhotic livers exhibited either an increase or decrease. In contrast, active matrix metalloproteinase-2, which was absent in normal liver, was elevated in fibrolamellar hepatocellular carcinoma as compared to cirrhotic liver and conventional hepatocellular carcinoma. Surprisingly, 10/12 cirrhotic livers and 2/4 fibrolamellar hepatocellular carcinomas but only 1/9 hepatocellular carcinomas were enriched for plasmin. The combined data suggest that the hepatocyte growth factor and plasmin systems tend to be operative in hepatocellular carcinoma and cirrhotic liver, more than fibrolamellar hepatocellular carcinoma. Furthermore, matrix turnover appears to be a more prominent feature of fibrolamellar hepatocellular carcinoma. These findings provide insight into the behavioral differences between hepatocellular carcinoma and the fibrolamellar variant.     

Expression of augmenter of liver regeneration (ALR) in human liver cirrhosis and carcinoma

AIMS: To determine the expression of a protein termed augmenter of liver regeneration (ALR), recently found to have a specific and beneficial effect on the process of liver regeneration in normal and diseased human liver. METHODS AND RESULTS: ALR expression in normal and cirrhotic human livers with various underlying diseases as well as in tissue samples of hepatocellular carcinoma (HCC) and cholangiocellular carcinoma (CCC) was analysed by immunohistochemistry and quantitative reverse transciptase-polymerase chain reaction (RT-PCR). Expression analysis of ALR in total liver protein extracts by Western blotting showed mainly dimeric ALR protein. Immunohistochemically, cytosolic and perinuclear immunosignals were found in hepatocytes and cholangiocytes in normal, cirrhotic or cancerous liver tissue and only weak signals in some endothelial cells in normal livers. Quantitative mRNA analysis revealed significantly increased ALR expression in cirrhosis compared with normal liver tissue. In HCC and CCC ALR mRNA expression was also significantly enhanced compared with normal liver tissue, but expression levels did not differ from the matching non-neoplastic tissue in the same patient. CONCLUSIONS: The findings suggest an important role for ALR in hepatocellular regeneration in liver cirrhosis as well as in hepatocarcinogenesis and therefore its potential value in the clinical diagnosis of hepatic cirrhosis and cancer.     

Hepatitis B antigen in the liver cells in cirrhosis and hepatocellular carcinoma.

The demonstration of hepatitis B antigen in the liver cells in formalin fixed paraffin embedded tissues by Shikata's orcein staining method affords an opportunity to conduct retrospective studies on necrospy materials. Such a study in Singapore showed orcein-positive liver cells in 22 out of 52 (42.3%) and 37 out of 50 (74.0%) cases of cirrhosis of the liver and hepatocellular carcinoma respectively, while only 5 out of 113 (4.4%) 'normal' livers gave positive results. There is a significant difference in the frequency of hepatocellular carcinoma in orcein-positive and orcein-negative cirrhotic livers (28 out of 50, 10 out of 40 respectively). These results suggest a possible aetiological relationship between hepatitis B antigen and hepatocellular carcinoma.     

Aetiology of cirrhosis, hepatic fibrosis, and hepatocellular carcinoma.

Histological study of 69 cases of cirrhosis, 9 of severe generalised hepatic fibrosis, and 19 of hepatocellular carcinoma showed an association with alcohol, hepatitis B surface antigen (HBsAg) or a1-antitrypsin bodies in, respectively, 41 (cirrhosis), 5 (fibrosis), and 9 (carcinoma). Eight of the cirrhotic cases and two of the carcinoma cases had double associations, HBsAg being present in all. Torcein and aldehyde fuchsin staining gave both false positive and false negative results when compared with immunofluorescence and immunoperoxidase methods for HBsAg. Large amounts of copper were found in four cirrhotic livers, and moderate amounts in 13: the diagnostic value of copper staining is questioned.     

Hepatocyte proliferation rate is a powerful parameter for predicting hepatocellular carcinoma development in liver cirrhosis.

AIMS: A sound predictive test is lacking for the identification of cirrhotic patients at high risk of developing hepatocellular carcinoma. The present study evaluates the measurement of hepatocyte expression of silver stained nucleolar organiser region (AgNOR) proteins as a risk factor for the development of hepatocellular carcinoma in cirrhosis. METHODS: Liver biopsies from 176 cirrhotic patients included in a follow up surveillance programme for hepatocellular carcinoma development were evaluated prospectively for hepatocyte AgNOR protein quantity. The follow up programme consisted of clinical and biochemical assessment every three months, and ultrasound scanning and serum alpha-fetoprotein (alpha FP) assessment every six months. Histological sections from the needle biopsies performed at enrollment were stained selectively for AgNOR proteins and the percentage of hepatocytes with an AgNOR protein area > or = 7 micron 2, indicative of a proliferative state (AgNOR proliferation index (AgNOR-PI)), was measured. RESULTS: During the mean (SD) follow up time of 65.5 (36.29) months (range, 12-143; median, 67), hepatocellular carcinoma was diagnosed in 48 of 176 patients (27.3%). The AgNOR-PI of the whole series ranged from 0% to 5% (median, 0.9%), and was significantly higher in patients with liver cell dysplasia and hepatitis B surface antigen (HBsAg) positivity (p < 0.0001 and p = 0.0002, respectively). The 176 patients were divided into two groups according to their AgNOR-PI scores; a cut off value of 2.5% defined by the receiver operating characteristic curve and the Youden index was used. Forty two patients were included in the high AgNOR-PI (< 2.5%) group, and 134 patients the low AgNOR-PI (< 2.5%) group. In the high AgNOR-PI group, 25 of 42 patients developed hepatocellular carcinoma, in contrast to only 23 of 134 patients (17.2%) in the group with a low AgNOR-PI (p < 0.0001). Hepatocellular carcinoma development was also significantly more frequent in patients with liver cell dysplasia and HBsAg positivity. Multivariate analysis using AgNOR-PI, liver cell dysplasia, HBsAg positivity, and hepatitis C virus (HCV) infection as covariates demonstrated that the AgNOR-PI parameter was the only significant predictor of hepatocellular carcinoma development. CONCLUSIONS: These results demonstrate that a high hepatocyte proliferation rate is a major risk factor for hepatocellular carcinoma development in the cirrhotic liver. Therefore, the evaluation of the hepatocyte proliferation rate is very important to identify patients requiring a more strict follow up programme for early diagnosis of hepatocellular carcinoma.     

Präneoplasien der Leber Definition – Differenzialdiagnose – klinische Konsequenz

The great advances in radiological imaging techniques and their widespread availability have focused attention on hepatic premalignant nodular lesions. The histological differential diagnosis of these nodules can often be difficult, especially in needle biopsy specimens with limited material. Diagnostic considerations differ significantly between livers with and without cirrhosis: In the noncirrhotic liver, the differential diagnosis includes liver cell adenoma, nodular regenerative hyperplasia, and hepatocellular carcinoma. In cirrhosis, dysplastic nodules (low and high grade), dysplasia (large and small cell) as well as hepatocellular carcinoma may occur. The standardization and the uniform use of the nomenclature of these entities are necessary for a better understanding of the biological nature and etiopathology of these lesions. Only a commonly accepted nomenclature makes a comparison of different therapeutic treatment regimens feasible.     

Vitronectin in the cirrhotic liver: An immunomarker of mature fibrosis

Vitronectin (Vn) is a multifunctional plasma glycoprotein produced by hepatocytes. Vn has been studied extensively as a cell adhesion molecule. However, its localization in the hepatic extracellular matrix has received relatively little attention. Cryosections of 5 normal liver samples and of 20 specimens showing posthepatitic cirrhosis were stained by the avidin-biotin complex method with a well-characterized monoclonal antibody to Vn. The extent and intensity of immunostaining were assessed semiquantitatively (0, no staining; 1+, weak focal staining; 2+, strong focal staining; 3+, strong diffuse staining). Paraffin sections from the same samples were stained with Masson trichrome (MT) and Shikata orcein (Or) methods. Frozen samples from selected cases were analyzed by Western blotting. In the normal liver, 3+ staining was limited to portal vessels. The portal tract connective tissue showed minimal staining (0 to 1+). Cirrhotic septa showed strong staining (2+). Septa lacking significant inflammation and composed of dense connective tissue, as indicated by MT and Or stains, showed the strongest Vn reactions (3+). Immunoblotting data strongly correlated with Vn increase in cirrhotic livers. Vn immunoreactivity is markedly increased in the cirrhotic liver matrix, regardless of the documented decrease in plasma Vn. Binding to collagen, elastin, and proteoglycans is the current favored mechanism of Vn deposition in tissues. Previous studies in cirrhotic patients showed increased affinity of plasma Vn to collagen. Vn is also increased in aged skin, associated with dermal elastic fibers. In other tissues, Vn deposition reflects chronicity of injury. Therefore, Vn immunoreactivity in liver can be considered a marker of fibrosis, especially of chronic/mature fibrosis, paralleling previous observations on enhanced orcein staining of cirrhotic septa. Immunolabeling of biopsy specimens with Vn and tenascin, a marker of ongoing remodeling or recently formed fibrous tissue, could be diagnostically helpful.