Hepatocellular carcinoma with sarcomatous change

We studied clinicopathological and immunohistochemical features of hepatocellular carcinoma (HCC) with sarcomatous change among surgically resected HCC cases. Among 308 HCC cases, 6 (1.9%) showed partial (5 cases) or entire (1 case) sarcomatous change. Only 1 case received preoperative anti-cancer therapy among the 6 cases, suggesting that sarcomatous change is not always related to anti-cancer therapy. Immunohistochemically, the sarcomatous components were positive for albumin and alpha 1-antichymotrypsin and negative for alpha-fetoprotein in all cases. Expressions of intermediate filament-related proteins (e.g., cytokeratin and vimentin) in the sarcomatous components were heterogeneous. The sarcomatous components showed stronger expressions of p53 protein and/or mouse double minute-2 protein, and higher proliferating cell nuclear antigen labeling index, suggesting their high proliferative activity and high malignant potential.

Is histological diagnosis of primary liver carcinomas with fibrous stroma reproducible among experts?

AIMS

In the era of targeted therapeutics, histological typing of hepatobiliary carcinomas has major clinical implications. Little is known about the reproducibility of the pathological diagnosis of primary liver carcinomas. Therefore, this study aimed to evaluate the worldwide variation in the pathological expert diagnoses of primary liver carcinomas with fibrous stroma in patients who did not have cirrhosis.

METHODS

A single set of slides was selected from 25 tumours, and this set was reviewed independently by 12 pathologists who have worldwide expertise in liver tumours. Reproducibility of the diagnoses was evaluated by Light's kappa, and diagnoses were clustered by multidimensional scaling. Immunohistochemistry was performed after histological review.

RESULTS

The interobserver reproducibility for diagnosis of hepatocellular carcinoma subtypes and cholangiocarcinomas was poor (kappa 0.23-0.52), even when the experts considered that the diagnosis required no additional stains or clinical information. Interestingly, multidimensional scaling revealed three main clusters of tumours: hepatocellular carcinoma with no other specifications (n = 13), fibrolamellar hepatocellular carcinoma (n = 3) and cholangiocarcinoma (n = 9). Using immunohistochemistry, these histological clusters correlated with expression of anti-hepatocyte and anti-cytokeratin 19 (p<0.001).

CONCLUSIONS

The results demonstrate the poor reproducibility among experts of the pathological diagnosis of primary liver carcinomas with fibrous stroma in patients who did not have cirrhosis, and highlight that the systematic use of immunohistochemistry may improve the diagnostic accuracy.

Spreds, inhibitors of the Ras/ERK signal transduction, are dysregulated in human hepatocellular carcinoma and linked to the malignant phenotype of tumors

Aberrant activation of the Ras/Raf-1/extracellular-regulated kinase (ERK) pathway has been shown to be involved in the progression of human hepatocellular carcinoma (HCC). However, the mechanism of dysregulation of ERK activation is poorly understood. Recently, we identified Sprouty-related protein with Ena/vasodilator-stimulated phosphoprotein homology-1 domain (Spred) as a physiological inhibitor of the Ras/Raf-1/ERK pathway. In this study, we found that the expression levels of Spred-1 and -2 in human HCC tissue were frequently decreased, comparing with those in adjacent non-tumorous tissue. Moreover, Spred expression levels in HCC tissue were inversely correlated with the incidence of tumor invasion and metastasis. Forced expression of Spred-1 inhibited HCC cell proliferation in vitro and in vivo, which was associated with reduced ERK activation. Spred-1 overexpression also reduced the secretion of matrix metalloproteinase-9 (MMP-9) and MMP-2, which play important roles in tumor invasion and metastasis. In addition, Spred-1 inhibited growth factor-mediated HCC cell motility. These data indicate that the reduction of Spred expression in HCC is one of the causes of the acquisition of malignant features. Thus, Spred could be not only a novel prognostic factor but also a new therapeutic target for human HCC.

SEN virus infection in patients with hepatocellular carcinoma

Although most cases of hepatocellular carcinoma (HCC) are associated with either the hepatitis B or C viruses (HBV, HCV), about 10-20% of HCCs occur in patients with chronic hepatitis that is aetiologically undefined. The aim of the present study was to determine the prevalence of the transfusion-transmitted SEN virus (SEN-V) in patients with HCC, including those patients who do not otherwise appear to be infected with HBV or HCV. Fragments of SEN-V subtypes D and H were amplified separately by PCR from the sera of 50 patients with HCC (31 from Canada and 19 from Japan) as well as from HCC and adjacent nontumourous liver tissues from eight of the Canadian patients. SEN-V DNA was found in the serum of 10 of 31 (32%) Canadian patients and eight of 19 (42%) Japanese patients [overall, 18 of 50 (36%) HCC patients]. SEN-V DNA was detected in the serum of 10 of 23 (43%) HCC patients with antibody to HCV (anti-HCV), six of 11 (55%) with hepatitis B surface antigen (HBsAg), and two of 16 (12%) without detectable anti-HCV or HBsAg. Twenty-three HCC patients in this study had 'silent HBV,' characterized by the detection of HBV DNA in the absence of HBsAg; eight of these (35%) also had SEN-V infections. SEN-V DNA was detected in HCC patients most typically in those with coexistent HBV or HCV infection. SEN-V was found in only one of seven HCC patients without HBV (without HBsAg or HBV DNA) or HCV and thus does not appear to be an important cause of 'cryptogenic' HCC.

HBsAg-negative hepatitis B virus infections in hepatitis C virus-associated hepatocellular carcinoma

This study was conducted to evaluate reports that hepatitis B virus (HBV) DNA sequences can be found in the serum and/or tumour tissue from some hepatocellular carcinoma (HCC) patients who have no detectable hepatitis B surface antigen (HBsAg) in their sera. Such HBV infections would be highly atypical, because prospective studies have shown a clear succession of specific serologic markers during and after most HBV infections. As most HBsAg-negative HCC patients in Japan have hepatitis C virus (HCV) infections, the present study was conducted to determine whether some of these patients actually have unrecognized HBV infections. Thirty newly diagnosed HCC patients from Kurume, Japan, with antibody to the hepatitis C virus (anti-HCV) were studied. None of the 30 had HBsAg detectable in their serum. Of 22 for whom test results for antibodies to the hepatitis B core antigen (anti-HBc) and antibodies to HBsAg (anti-HBs) were available, 14 (64%) had anti-HBc and anti-HBs, four (18%) had anti-HBc alone, and four (18%) had no HBV markers. Nested polymerase chain reaction was used to detect the HBV surface (S), core (C), polymerase (P) and core promoter gene sequences in the HCC tissues and in the adjacent nontumorous liver tissues. HBV DNA was detected in HCC and/or adjacent nontumorous liver in 22 of 30 (73%) patients [detected in both HCC and nontumorous liver in 19/30 patients (63%)]. Among the 22 patients with detectable HBV DNA, more than one HBV gene was detected in 10 (46%). Among the four patients whose sera were negative for all HBV markers, three had HBV DNA in either HCC and nontumorous liver (two cases) or only in the nontumorous liver (one case); HBV DNA could not be detected in tissues from the fourth patient. In 18 of 21 (86%) patients with detectable HBV core promoter sequences, mutations at both nucleotides 1762 (A-GT) and 1764 (G-A) in the core promoter region were found. No deletions were detected in the core promoter gene region of the type reported to be associated with some cases of HBsAg-negative HBV infection. Thus, HBV DNA was detectable in 22 (73%) HBsAg-negative, anti-HCV-positive HCCs, including three (10%) who were also negative for anti-HBc and anti-HBs. HBV mutations at both nucleotides 1762 (A-GT) and 1764 (G-A) in the core promoter region were found in the majority of cases, mutations that have previously been reported in HBV that is integrated in HCC DNA. In serologic surveys to determine etiologic associations of HCC, patients such as those in this study would have been incorrectly designated as having 'HCV-associated HCC,' whereas the data in this study suggest that HBV could have played a role in the development of their HCCs.

Integration of hepatitis B virus containing mutations in the core promoter/X gene in patients with hepatocellular carcinoma

Integration of hepatitis B virus is thought to be an essential step in hepatitis B virus associated hepatocarcinogenesis. Mutations at nucleotides 1762 and 1764 in the hepatitis B virus, within a sequence encoding both the core promoter gene and the X gene, have been found frequently in patients with hepatocellular carcinoma. However, integration of these mutant sequences has not been reported to date.

METHODS

A 228-base pair segment of the hepatitis B virus core promoter gene was amplified from hepatocellular carcinomas and adjacent non-tumourous liver tissue by nested PCR and sequenced. Integration of hepatitis B virus into human genomic DNA was investigated using the 'genome walking' method.

RESULTS

Point mutations were found in both hepatitis B virus nucleotides 1762 and 1764 in 8 of 14 hepatocellular carcinoma tissues (57%) and in 11 of 14 adjacent non-tumourous liver tissues (79%). Three patients were evaluated using the 'genome walking' method; all were found to have hepatitis B virus DNA integrated in their hepatocellular carcinoma (two patients) and/or in their non-tumourous liver tissue (three patients). Integration occurred in all tissues near host genomic sites that are prone to integration. Hepatitis B virus was integrated at or near the hepatitis B virus DR1 site in all samples, and all contained truncated X gene sequences that have been reported to be capable of producing fusion transcripts with transactivation potential.

CONCLUSIONS

Integrated hepatitis B virus DNA containing core promoter mutations at nucleotides 1762 and 1764 was found in hepatocellular carcinoma and/or adjacent non-tumourous liver tissue of three patients. These findings leave open the possibility that insertional mutagenesis or transactivation by fusion transcripts resulting from hepatitis B virus integration could play a role in hepatocarcinogenesis in some patients.

Recurrence of hepatocellular carcinoma: multicentric occurrence or intrahepatic metastasis? A viewpoint in terms of pathology

Recurrence after successful surgical or nonsurgical treatment of hepatocellular carcinoma (HCC) is caused either by intrahepatic metastasis or by metachronously multicentric occurrence. Intrahepatic metastasis is a major cause of recurrence of advanced HCCs with varying degrees of vascular invasion, and multicentric occurrence is a frequent cause of recurrence in small HCCs with no obvious vascular invasion. It is estimated that at least 20% of small HCCs have a high probability of recurrence due to multicentric occurrence, based on the finding that adenomatous hyperplasia (AH) and/or atypical adenomatous hyperplasia (AAH), which are considered premalignant lesions, are found in the vicinity of resected small HCCs with liver cirrhosis. However, because neither AH nor AAH occur in HCC cases without liver cirrhosis, most recurrence of HCC in noncirrhotic liver is considered to be due to intrahepatic metastasis or to de novo hepatocarcinogenesis. In a survey of autopsy cases of liver cirrhosis with small HCC, smaller HCC nodules were found in other liver slices in 50% of cases, and it is estimated that approximately 50% of HCC is already multicentric in the early stage.

Immunohistologic study on the expressions of alpha-fetoprotein and protein induced by vitamin K absence or antagonist II in surgically resected small hepatocellular carcinoma

Sixty-eight cases of single hepatocellular carcinoma (HCC) with less than 3 cm of diameter were immunohistochemically examined for the expressions of alpha-fetoprotein (AFP) and protein induced by vitamin K absence or antagonist II (PIVKA-II). In cancerous tissues, the expression rate was significantly higher for PIVKA-II (34 cases [50%]) than AFP (21 cases [31%]) (P <.05), suggesting a higher specificity of PIVKA-II to small HCC. Sixteen of the 68 cases (24%) were positive to both AFP and PIVKA-II, and in 8 of the 16 cases, AFP and PIVKA-II expressing areas within a nodule were clearly divided by a fibrous septum. According to histologic grades, PIVKA-II expression was confirmed in 2 of the 15 well-differentiated HCCs, and in the well-differentiated component of 6 of the 12 "nodule-in-nodule"-type well-differentiated HCCs. AFP expression was not found in well-differentiated HCCs, but found in 16 of the 40 moderately differentiated HCCs (40%) and in the moderately differentiated component of 3 of the 12 "nodule-in-nodule"-type well-differentiated HCCs. The positive rate in the tissues was correlated to the serum levels for both AFP and PIVKA-II. In addition, frequency of tissue-PIVKA-II expression was higher than tissue-AFP expression in the cases whose serum protein level was within the normal range. This indicates that AFP and PIVKA-II have different patterns of tissue expression and of secretion to the blood. In comparison with tissue-AFP-negative cases, tissue-AFP-positive HCCs had a larger tumor size, higher frequencies of portal vein invasion and intrahepatic metastasis, a high Ki-67 labeling index, and a lower rate of recurrence-free survival. Thus, tissue-AFP-positive HCCs are suggested to be biologically more malignant than those HCCs that are AFP-negative and PIVKA-II-positive.

Laminin deposition to type IV collagen enhances haptotaxis, chemokinesis, and adhesion of hepatoma cells through beta1-integrins

BACKGROUND/AIMS

In hepatocellular carcinoma, laminin deposition to type IV collagen along the sinusoids is observed with the development of arterial network, coinciding with intrahepatic metastasis. We investigated the influence of laminin deposition to type IV collagen on hepatoma cell adhesion, motility and secretion of matrix metalloproteinases (MMPs), which are indispensable behaviors for tumor metastasis.

METHODS

Hepatoma cell lines (KYN-1, -2 and -3) were used. The expression of integrin subunit mRNAs in hepatoma cells was confirmed by RT-PCR. The influence of laminin addition to type IV collagen on the adhesion, chemokinesis, and migration of KYN-1, -2 and -3 was evaluated by the haptotactic migration, phagokinetic track motility, and cell adhesion assays. The effects of integrin subunits on these activities were evaluated using the function-blocking antibodies for integrins. Phosphorylation of MEK1/2 and secretion of MMPs were investigated by Western blotting and gelatin zymography.

RESULTS

Integrin alpha1, alpha2, alpha3, alpha6 and beta1 subunit mRNAs were detected. The combination of type IV collagen and laminin enhanced the migration, chemokinesis, and adhesion of hepatoma cells compared to that of type IV collagen when used alone. The enhanced activity was significantly suppressed by function-blocking antibodies for integrin alpha1, alpha2, alpha3, alpha6 and beta1 subunits. Hepatoma cells cultured on the combination of type IV collagen and laminin showed phosphorylation of MEK1/2 and increased secretion of MMPs.

CONCLUSIONS

The addition of laminin to type IV collagen enhances hepatoma cell adhesion and motility through beta1-integrins.

Expression of angiogenic factors, basic fibroblast growth factor and vascular endothelial growth factor, in human biliary tract carcinoma cell lines

In order to clarify angiogenic mechanism in biliary tract carcinoma, expressions and functions of basic fibroblast growth factor (bFGF) and its receptors (FGFR-1-4), and vascular endothelial growth factor (VEGF) and its receptors were investigated by using human biliary tract carcinoma cell lines (KMC-1, KMC-2, KMBC and KMG-C). Expression of bFGF was confirmed in KMC-1 and KMC-2, and that of FGFR-1-4 in all the cell lines except no FGFR-2 in KMC-2. Expression of VEGF was detected in all the cell lines, whereas the cell lines did not express VEGF receptors. Addition of anti-bFGF neutralizing antibody to the medium did not suppress cell proliferation, whereas exogenous bFGF with or without heparin accelerated cell proliferation in all cell lines. Addition of anti-bFGF neutralizing antibody or anti-VEGF neutralizing antibody to the co-culture of human umbilical vascular endothelial cells (HUVEC) and KMC-2 suppressed the proliferation of HUVEC. Surgically obtained cholangiocarcinoma tissues (n=7) were immunohistochemically negative to bFGF, while six of the seven were positive to VEGF. These findings suggested that human biliary tract carcinoma cells express both bFGF and VEGF not as autocrine growth factors but as angiogenic factors. On the other hand, expression of VEGF was found at a higher frequency than bFGF both in the cell lines and tissues.

Involvement of p21(WAF1/Cip1), p27(Kip1), and p18(INK4c) in troglitazone-induced cell-cycle arrest in human hepatoma cell lines

Peroxisome proliferator-activated receptor gamma (PPARgamma) regulates cell growth and differentiation. Recent evidence has suggested that PPARgamma ligands had anti-tumor effects through inhibiting cell growth and inducing cell differentiation in several types of malignant neoplasm. In the present study, we investigated: 1) the expression of PPARgamma in both human hepatoma cell lines and 5 resected human hepatocellular carcinoma (HCC) tissues; 2) the growth-inhibitory effect of troglitazone, a PPARgamma ligand, on those hepatoma cells; and 3) the molecular mechanisms of troglitazone-induced cell-cycle arrest. Five hepatoma cell lines, HLF, HuH-7, HAK-1A, HAK-1B, and HAK-5, were used. The mRNA expression levels of PPARgamma, p21(WAF1/Cip1), and p27(Kip1) were determined by real-time quantitative reverse transcription-polymerase chain reaction. The expression of cell cycle-regulating proteins, such as p21, p27, p18(INK4c), cyclin E, and pRb, was examined using Western blotting. PPARgamma was constitutively expressed in all the cell lines and the HCC tissues used in this study. A cytostatic effect of troglitazone was found in those cell lines, and this inhibition of cell growth was dosage-dependent. G0/G1 arrest was apparently demonstrated in flow cytometric analysis in HLF, HAK-1A, HAK-1B, and HAK-5, all of which showed an increased expression of p21 protein. However, HuH-7, lacking p21 protein expression, did not demonstrate clear arrest in the cell-cycle analysis. HLF, which was deficient in the protein product of the retinoblastoma tumor-suppressor gene (pRb), responded most profoundly to troglitazone, showing an increased expression in not only p21, but also in p27 and in p18. These findings suggested that p21, p27, and p18 might be involved in troglitazone-induced cell-cycle arrest in human hepatoma cells.

Clinicopathologic study on cholangiolocellular carcinoma

We clinicopathologically studied 6 resected cases of cholangiolocarcinoma (CLC) including 2 referred cases from other hospitals. The frequency of CLC was 0.56% of the 708 consecutively resected cases of primary liver cancer and the mean age of CLC cases was 66 years. Three of the 6 cases (50%) were hepatitis C virus antibody (HCVab) positive, one (17%) was hepatitis B virus surface antigen (HBsAg) positive, and 2 (33%) were negative to both HCVAb and HBsAg. Serum levels of alpha-fetoprotein were slightly elavated only in 1 case. Clinically, 4 cases were diagnosed as hepatocellular carcinoma (HCC) and 2 cases as cholangiocellular carcinoma (CCC). Grossly, CLCs were whitish in color and solid, not encapsulated, and resembled CCC. Histologically, the tumor cells had eosinophilic cytoplasm with ovoid nuclei, and mild atypia. The tumor proliferated in an anastomosing pattern of Hering's canal-like small glands with an abundant fibrous stroma. Four of the 6 tumors (83%) consisted of only CLC and other 2 tumors contained CCC-like area and HCC-like area in a part of the nodules, respectively. Immunohistochemically, all tumors were positive to cytokeratin (CK) 7. CK8 were also positive in all of 6 cases. These results revealed that CLC had the clinical features resembling HCC but the morphologic features resembling CCC. It is suggested that CLC cells might be derived from Hering's canal or stem cells which have the intermediate features between hepatocytes and bile duct epithelium.

Premalignant lesions of hepatocellular carcinoma: pathologic viewpoint

The significance of large cell dysplasia and small cell dysplasia as premalignant lesions has been extensively discussed. At present the majority of researchers consider that the former seems to be a secondary change rather than a premalignant lesion, and the latter is strongly suggested to be a premalignant lesion. In the past decade, however, adenomatous hyperplasia (dysplastic nodules), the nodular lesions seen in the cirrhotic liver, has attracted researchers' interest. The significance of adenomatous hyperplasia as a premalignant lesion has been supported by its frequent occurrence in the vicinity of hepatocellular carcinomas (HCC), the presence of adenomatous hyperplasia containing distinct cancerous foci, frequent malignant transformation seen in follow-up studies, and so forth. For histological diagnosis of adenomatous hyperplasia, a thorough understanding of the pathology of well-differentiated HCC at an early stage is essential. Reports from Europe and the United States on dysplastic nodules often include well differentiated HCC at the early stage, possibly because of the lack of opportunity for Western pathologists to see minute early-stage well differentiated HCC. In addition, Western pathologists usually have no concept of "carcinoma in situ" in which no obvious invasive growth is present, and many cases of gastric cancer in the mucosa are diagnosed as dysplasia in Europe and the United State.

Clinicopathologic study on cholangiolocellular carcinoma

We clinicopathologically studied 6 resected cases of cholangiolocarcinoma (CLC) including 2 referred cases from other hospitals. The frequency of CLC was 0.56% of the 708 consecutively resected cases of primary liver cancer and the mean age of CLC cases was 66 years. Three of the 6 cases (50%) were hepatitis C virus antibody (HCVab) positive, one (17%) was hepatitis B virus surface antigen (HBsAg) positive, and 2 (33%) were negative to both HCVAb and HBsAg. Serum levels of alpha-fetoprotein were slightly elavated only in 1 case. Clinically, 4 cases were diagnosed as hepatocellular carcinoma (HCC) and 2 cases as cholangiocellular carcinoma (CCC). Grossly, CLCs were whitish in color and solid, not encapsulated, and resembled CCC. Histologically, the tumor cells had eosinophilic cytoplasm with ovoid nuclei, and mild atypia. The tumor proliferated in an anastomosing pattern of Hering's canal-like small glands with an abundant fibrous stroma. Four of the 6 tumors (83%) consisted of only CLC and other 2 tumors contained CCC-like area and HCC-like area in a part of the nodules, respectively. Immunohistochemically, all tumors were positive to cytokeratin (CK) 7. CK8 were also positive in all of 6 cases. These results revealed that CLC had the clinical features resembling HCC but the morphologic features resembling CCC. It is suggested that CLC cells might be derived from Hering's canal or stem cells which have the intermediate features between hepatocytes and bile duct epithelium.

Expression and function of interleukin-8 in human hepatocellular carcinoma

Expression and functions of interleukin (IL)-8, a pro-inflammatory cytokine with angiogenesis action, was examined in 23 surgically resected hepatocellular carcinoma (HCC) specimens and 7 HCC cell lines. In all HCC tissues, IL-8 expression was confirmed with reverse-transcription polymerase chain reaction method and enzyme-linked immunosorbent assay, and immunohistochemistry showed HCC cells were the major producer of IL-8 in the tissues. Microvessel density was measured by the double immunohistochemical staining of muscular vessels in HCC tissues, but the density was not related to the level of IL-8 in the HCC tissues. On the other hand, in the co-culture of human umbilical vein endothelial cells (HUVEC) and a HCC cell line (KIM-1), IL-8 produced by KIM-1 significantly accelerated the proliferation of HUVEC. In addition, cases with a high IL-8 level in cancerous tissue had a significantly higher frequency of portal vein invasion, venous invasion and bile duct invasion (p<0.05). In the cultures of 7 HCC cell lines IL-8 secretion into culture medium increased with the treatment of IL-1beta or tumor necrosis factor-alpha. This showed IL-8 expression is regulated by inflammatory cytokines. IL-8 produced by HCC is an angiogenesis factor of HCC, but it could have a much more important role in the invasion and metastasis of HCC.

Expression of Hu-IFN-alphaR2 chain of type I interferon receptor in human hepatocellular carcinoma and non-cancerous tissues

Type I interferon (IFN) receptor consists of two chains (Hu-IFN-alphaR1 and Hu-IFN-alphaR2), and Hu-IFN-alphaR2 takes a soluble, short, or long form (Hu-IFN-alphaR2a, Hu-IFN-alphaR2b, or Hu-IFN-alphaR2c, respectively). We examined Hu-IFN-alphaR2 expression in hepatocellular carcinoma (HCC) tissues and their corresponding non-cancerous (non-HCC) tissues. Immunohistochemically, Hu-IFN-alphaR2 expression was positive in 53 (77%) of 69 HCC tissues and in 61 (88%) of 69 non-HCC tissues. Hu-IFN-alphaR2 protein in tissue homogenates of HCC and non-HCC tissues obtained from 29 patients was measured by using ELISA kits, and the amount was 12.7+/-10.9 pg/mg protein in HCC tissue and 10.5+/-5.0 pg/mg protein in non-HCC tissue. Number of specimens in which Hu-IFN-alphaR2 level was 3 pg/mg protein or lower, or 20 pg/mg protein or higher, was one each for non-HCC, while it was 7 (24%) and 6 (21%) for HCC. RT-PCR analysis was done in 7 of the 29 HCC cases. It revealed both Hu-IFN-alphaR2a and Hu-IFN-alphaR2c were expressed in all HCC tissues and in 6 of the 7 non-HCC tissues, and Hu-IFN-alphaR2b was expressed in all HCC tissues and in 4 of the 7 non-HCC tissues. Because immunostaining intensity of Hu-IFN-alphaR2 tended to be higher in the areas with active inflammation, effects of inflammatory cytokines (IL-1alpha, IL-1beta, and TNF-alpha) on Hu-IFN-alphaR2 expression were examined on 11 HCC cell lines. As a result, TNF-alpha up-regulated Hu-IFN-alphaR2 expression in 7 of the 11 cell lines. In 3 of the 7 cell lines, up-regulation of Hu-IFN-alphaR2 on cell surface, as well as of the soluble form of Hu-IFN-alphaR2, was induced not only by TNF-alpha, but also by IL-1alpha or IL-1beta. In conclusion, both HCC and non-HCC tissues frequently express Hu-IFN-alphaR2c that is necessary for Type I IFN response. Hu-IFN-alphaR2 expression in HCC tissues is often attenuated or enhanced, and may be regulated by inflammatory cytokines.

Results of surgical and nonsurgical treatment for small-sized hepatocellular carcinomas: a retrospective and nationwide survey in Japan. The Liver Cancer Study Group of Japan

Hepatic resection (HX), percutaneous ethanol injection (PEI), and transcatheter arterial embolization (TCAE) have all been used in the treatment of patients with small-sized hepatocellular carcinomas (HCCs). However, the indications for these therapeutic modalities remain unclear. Therefore, the first step to minimize the debate on these indications is to review the standard results from each treatment based on an extensive survey. The participants in this study were patients with HCCs less than 5 cm in diameter who were enrolled in The Liver Cancer Study Group of Japan. The survival rates in the HX (n = 8,010), PEI (n = 4,037), and TCAE (n = 841) groups were calculated in relation to the number of tumors and the clinical stage. In the clinical stage I cases with a solitary tumor less than 2 cm in diameter and in all clinical stages with a solitary tumor greater than 2 cm and in the clinical stage II cases with 2 tumors greater than 2 cm, the HX group showed higher survival rates than the nonsurgical groups. The HX group had a higher male/female ratio and a younger mean age than the PEI or TCAE group. The ratio of HBs antigen-positive cases/hepatitis C virus antibody-positive cases in the PEI group was lower than that in the corresponding HX group. In contrast, the PIVKA-II values in the HX group tended to be higher than in the PEI group. In conclusion, these findings will provide useful information for selection of a therapeutic modality for small-sized HCCs.

Clinicopathologic study on hepatocellular carcinoma negative for hepatitis B surface antigen and antibody to hepatitis C virus

Among 326 consecutively resected cases of hepatocellular carcinoma (HCC), we studied clinicopathologic features of 13 cases (NBNC-HCC) negative for hepatitis B surface antigen (HBsAg), antibody to HBsAg (HBsAb), antibody to hepatitis B core antigen (HBcAb), hepatitis B envelope antigen (HBeAg), antibody to HBeAg (HBeAb), and antibody to hepatitis C virus (HCVAb). Forty-four HCC cases positive only for HBsAg (B-HCC) and 232 cases positive only for HCVAb (C-HCC) were studied as controls. Clinically, NBNC-HCC cases showed good liver function reserve. None of NBNC-HCC cases had periodic medical check ups and HCC was detected in 12 cases (92.3%) incidentally. Pathologically, the mean tumor diameter was significantly larger and the histologic grade was less differentiated in NBNC-HCC cases than in B-HCC and C-HCC cases. In the background liver, liver cirrhosis was associated in 15.4% of NBNC-HCC cases, 50.0% of B-HCC and 38.2% of C-HCC cases. The degree of inflammation and fibrosis was less in NBNC-HCC cases, and two cases (15.4%) had almost normal liver histology. In NBNC-HCC cases, synchronous and metachronous multicentric occurrence was not observed. In B-HCC cases, synchronous multicentric occurrence was found in 1 case (20.0%), but no metachronous multicentric occurrence. In C-HCC cases, synchronous and metachronous multicentric occurrence was found in 13 (43.3%) and 8 (30.8%) cases, respectively. However, the cumulative recurrence-free rate was not significantly different among the three groups. Accordingly, it was suggested that better prognosis could be expected in NBNC-HCC cases compared with B- and C-HCC cases, if the cancer could be detected in the early stage.

Bright loop appearance; a characteristic ultrasonography sign of early hepatocellular carcinoma

Ultrasonography (US) and computed tomography (CT) are the most effective screening methodologies for hepatocellular carcinoma (HCC). In our US screening, 20% of small HCC nodules less than 20 mm in diameter were detected as hyperechoic tumors. Among these hyperechoic HCC nodules, we have often observed <bright loop appearance> (BL) which is defined as hypoechoic nodules in the hyperechoic tumor. In this study, we report that the BL is a sign of dedifferentiation of early stage of HCC with fatty change by US. From 1994 to 1998, we performed tumor targeting needle biopsy in 938 hepatic nodular lesions. Among them, 284 nodules <20 mm in diameter, histologically diagnosed as HCC, were studied. BL is defined as a hyperechoic tumor containing a hypoechoic nodule >4 mm in diameter by US. Among 284 nodules, well, moderately and poorly differentiated HCC were 183 (64.4%), 100 (35.2%) and 1 (0.4%), respectively. On US, hypoechoic, isoechoic, and hyperechoic nodules were 188 (66.2%), 32 (11.3%) and 64 (22.5%), respectively. Forty-seven nodules of 64 hyperechoic HCC nodules <20 mm in diameter, 47 nodules (73.4%) showed fatty changes. Of 64 hyperechoic HCC nodules, we recognized 22 nodules (34.4%) as BL. The proportion of BL type hyperechoic nodules increased with the tumor size. Two hyperechoic nodules followed by US changed to BL with tumor enlargement. Histologic examination of a resected HCC with BL showed that hyperechoic HCC nodule represented well-differentiated HCC with fatty change and inner hypoechoic lesion represented moderately differentiated HCC without fatty change. In US screening for HCC, BL was often observed in HCC nodules from 11 to 20 mm in diameter. Histologic examination revealed that BL of HCC on US was associated with tumor progression and indicated dedifferentiation showing moderately differentiated HCC in well-differentiated HCC with fatty change.

Pathomorphologic study on the mechanism of fatty change in small hepatocellular carcinoma of humans

BACKGROUND/AIMS

Fatty change is frequently observed in small hepatocellular carcinoma (HCC) of the early stage. However, the mechanism of fatty change and its pathomorphological features in small HCC are not yet fully understood. These issues are addressed here.

METHODS

Histological examinations were conducted on 260 HCC nodules (< or =3 cm in diameter) which were surgically obtained from 249 patients. According to the distribution pattern, fatty changes were classified into two types: 'diffuse type' when the change was found throughout the cancerous nodule; and 'focal type' when the change was localized in part of the nodule. To study the pathogenesis of fatty change in HCC in relation to angioarchitecture, the number of arterial tumor vessels and intratumoral portal tracts in 104 of the 260 nodules was counted.

RESULTS

Fatty change was found in 51 of the 260 nodules (19.6%), the frequency was highest (36.4%) in the nodules whose diameter was 1.1 to approximately 1.5 cm, and the frequency decreased with the increase in tumor diameter. Small well-differentiated HCCs were often associated with a diffuse type fatty change. With the increase in tumor diameter, moderately differentiated cancerous tissues without associated fatty change appeared, and the focal type was found more frequently. According to the angioarchitecture, in HCCs < or =1.5 cm, the number of intratumoral arteries was significantly smaller in HCCs with fatty change (p<0.05), though the number of intratumoral portal tracts was not significantly different compared with HCCs without fatty change.

CONCLUSION

These findings suggest that fatty change of small HCC is closely related to the tumor size, the histological grade and insufficient development of the arterial tumor vessels.

Expression and localization of vascular endothelial growth factor receptors in human hepatocellular carcinoma and non-HCC tissues

Flt-1 (VEGF receptor-1) and KDR/Flk-1 (VEGF receptor-2) are the high-affinity receptors for the angiogenesis factor, vascular endothelial growth factor (VEGF). VEGF expression has been confirmed in human hepatocellular carcinoma (HCC), and VEGF is thought to be involved in the angiogenesis within HCC tissues. However, expressions of VEGF receptors in HCC have not been reported. We immunohistochemically examined expressions and localizations of Flt-1 and KDR in 28 surgically resected HCC tissues. In non-cancerous area, Flt-1 and KDR were mainly found in macrophages including Kupffer cells; both receptors were found in vascular endothelial cells in the portal veins and arteries within portal tracts; and KDR was also found in some sinusoidal endothelial cells. In cancerous area, Flt-1 and KDR were found in some macrophages, and also in the endothelial cells of intratumoral blood vessels. In 25 moderately and/or poorly differentiated HCCs, KDR expression in the blood space endothelial cells was clear and continuous in 20 cases, and focal in 5 cases. These results suggest that there would be an angiogenesis mechanism via VEGF/Flt-1 or VEGF/KDR in HCC, and the VEGF/KDR system would take a more important role.

Kinetics of apoptotic cells in experimental autoimmune uveoretinitis

PURPOSE

To investigate the role of apoptosis in immunopathogenic mechanisms of experimental autoimmune uveoretinitis (EAU), the kinetics of apoptotic cells and expression of Fas and Fas ligand (FasL) in the eye with EAU were studied.

METHODS

Male inbred Lewis rats were immunized with S-antigen (40 microg/rat), and eyes were examined to detect apoptotic cells on days 1, 4, 8, and 10 post-immunization and days 0, 2, 4, 6, and 8 after the onset of EAU. The clinical and pathologic scores were used for estimating EAU. Apoptotic cells were analyzed by TdT-mediated dUTP nick-end labeling, electron microscopic and immunohistologic examinations, and agarose gel electrophoresis. The anti-rat Fas and anti-rat FasL antibodies were used to examine the expression of Fas and FasL.

RESULTS

Apoptotic cells were detected in the infiltrating cells in the aqueous humor, the vitreous body, the iris-ciliary body, and the retina. Apoptotic cells were observed as early as the day of EAU onset and reached a peak on day 2 after the disease onset. Fas and FasL were expressed on the infiltrating cells in the aqueous humor and the vitreous. FasL was expressed on resident cells of the ciliary body. The kinetics of the expression of FasL corresponded with the kinetics of apoptotic cells.

CONCLUSIONS

Fas-FasL-mediated apoptosis is considered to occur in the eye with EAU and plays a role in the immunopathogenic mechanisms to eliminate ocular infiltrating cells, thereby down-regulating the inflammatory processes.

Development of a TT virus DNA quantification system using real-time detection PCR

Although TT virus (TTV) was isolated from a cryptogenic posttransfusion hepatitis patient, its pathogenic role remains unclear. It has been reported that the majority of the healthy population is infected with TTV. To elucidate the differences between TTV infection in patients with liver diseases and TTV infection in the healthy population, a quantification system was developed. TTV DNA was quantified by a real-time detection PCR (RTD-PCR) assay on an ABI Prism 7700 sequence detector. With this system, TTV DNA was quantified in 78 hepatitis C virus (HCV)-infected patients (63 with elevated serum alanine aminotransferase [ALT] levels and 15 with normal ALT levels) and in 70 voluntary blood donors (BDs). The quantification range was 2.08 to 7.35 log copies/ml. The intra-assay and interassay coefficients of variation were 0.37 to 6.33% and 0.60 to 7.07%, respectively. The mean serum TTV DNA levels in the HCV-infected patients with both elevated and normal ALT levels and BDs were 3.69 +/- 0.89, 3.45 +/- 0.76, and 3.45 +/- 0.67 log copies/ml, respectively. Comparison of the serum TTV DNA levels among the HCV-infected patients revealed that they were not related to the serum ALT and HCV core protein levels or to the histopathological score on liver biopsy. This study showed that (i) the RTD-PCR assay for the detection of TTV was accurate and had a high degree of sensitivity, (ii) the mean serum TTV DNA level was similar among HCV-infected patients, irrespective of their ALT level, and also among BDs, and (iii) a high serum TTV DNA level does not affect the serum ALT and HCV levels or liver damage in HCV-infected patients.

Metachronous multicentric occurrence of hepatocellular carcinoma after surgical treatment - clinicopathological comparison with recurrence due to metastasis

This study investigated clinicopathological features of patients with recurrence of metachronous multicentric occurrence by comparison with patients with recurrence due to metastasis. In 177 patients, recurrences after curative surgical treatment were classified into recurrence due to metastasis according to criteria based on imaging findings. This group consisted of 35 patients. Among the rest of the patients, 59 underwent fine needle biopsies for recurrent tumor and, in these patients, a classification of recurrence of metachronous multicentric occurrence was made based on the histological findings of primary and recurrent tumor. This group consisted of 33 patients. The estimated incidence for recurrence of metachronous multicentric occurrence was 44.8% to total total patients. Metachronous multicentric occurrence frequently developed in patients with anti-HCV antibody and an early stage of primary tumor. In 80% of the patients who had recurrent tumor of multicentric origin, the recurrence developed within 3 postoperative years. The survival rate in patients with metachronous multicentric occurrence was significantly higher than that in patients with recurrence due to metastasis. Conclusively, the incidence of patients with recurrence of metachronous multicentric occurrence was high, but the prognosis for these patients was significantly better than that for patients with recurrence due to metastasis.

Histopathologic evaluation of hepatocellular carcinoma with special reference to small early stage tumors

Over the past decade extensive studies on small early stage hepatocellular carcinomas (HCCs) have defined their pathomorphologic features. Most early HCCs are well differentiated, with an ill-defined nodular appearance. Proliferation of well-differentiated small HCCs is closely related to tumor dedifferentiation. When a well-differentiated HCC reaches a size of about 1.0-1.5 cm in diameter, less-differentiated cancerous tissues with greater proliferative activity evolve within it. Such a phenomenon is often appreciated grossly and/or histologically as a "nodule-in-nodule" appearance. Subsequently, moderately to poorly differentiated HCC tissues gradually replace the initial surrounding HCC. This replacement of well-differentiated HCC tissue is completed when the tumor reaches a size of about 2-3 cm. Hyperplastic nodular lesions in cirrhotic livers may have a premalignant potency. HCC frequently occurs multicentrically whether synchronously or metachronously, defying complete cure by conventional therapies other than liver transplantation.

Integrin alpha6beta1 plays a significant role in the attachment of hepatoma cells to laminin

BACKGROUND/AIMS

Tumor invasion and metastasis consist of a series of complex events. During this process, the ability of tumor cells to adhere to laminin, a major component of basement membranes, is required at various steps. The expression of laminin-binding integrins and the extent of tumor metastasis and progression appear to be related. In hepatocellular carcinoma, increased expression of laminin-binding integrins is observed. However, little is known concerning the possible functional interactions between laminin-binding integrins and laminin. Therefore, we investigated the participation of laminin-binding integrins in the attachment of hepatoma cells to laminin.

METHODS

Human hepatoma cell lines (KIM-1, KYN-1, 2) were used. We investigated the expression of integrin alpha1, alpha2, alpha3, alpha6, beta1, and beta4 subunits on hepatoma cells by immunocytochemical and flow cytometric analysis. Participation of these integrin subunits in the attachment of hepatoma cells to laminin was evaluated by an inhibition of cell adhesion assay.

RESULTS

Integrin alpha1, alpha2, alpha3, alpha6 and beta1 subunits were expressed at the marginal areas of hepatoma cells, while the integrin beta4 subunit was scarcely detected. Laminin promoted the attachment of hepatoma cells in a dose-dependent manner. Although anti-integrin alpha1, alpha2, beta3 and beta4 subunit antibodies did not inhibit cell attachment to laminin, anti-integrin alpha6 and beta1 subunit antibodies inhibited the attachment by 50% or more.

CONCLUSIONS

These findings indicate that integrin alpha6beta1 is very important in the attachment of hepatoma cells to laminin, suggesting the participation of this integrin in metastasis and invasion of hepatoma cells.

Cell motility mediated by rho and Rho-associated protein kinase plays a critical role in intrahepatic metastasis of human hepatocellular carcinoma

Human hepatocellular carcinoma (HCC) can invade the portal vein and metastasizes to other parts of the liver even at a relatively early stage of the disease, with less tumor spread occurring outside the liver. This intrahepatic metastasis is the main cause of liver failure and death in HCC patients. To analyze the mechanisms of intrahepatic metastasis we have constructed metastatic models using orthotopic implantation of human HCC cell lines. Five HCC cell lines formed liver tumors after injection into the livers of SCID mice, and of those 5 cell lines, Li7 and KYN-2 cells also resulted in vascular tumor thrombi and intrahepatic metastasis. These 2 cell lines had markedly higher cell motilities than the other 3 cell lines in vitro. Their motilities appeared to be Rho-mediated; serum and lysophosphatidic acid (LPA) evoked actin reorganization and motility of Li7 cells, and C3 exoenzyme exposure reduced the motility of both serum-stimulated Li7 cells and KYN-2 cells. Dominant negative and active forms of p160 Rho-associated coiled-coil forming protein kinase (p160ROCK), one of the downstream effectors of Rho, were separately and stably introduced into Li7 cells. Dominant active p160ROCK transfectants showed increased motility that was independent of serum and LPA, and dominant negative p160ROCK transfectants showed reduced motility under stimulation. Furthermore, implantation of dominant negative p160ROCK transfectants resulted in a reduced metastatic rate in vivo compared with the parent cells or a control transfectant. These findings indicate that cell motility mediated by the Rho/p160ROCK signaling pathway plays a critical role in intrahepatic metastasis of human HCC.

Establishment and characterization of a new human hepatocellular carcinoma cell line, HAK-3, and its response to growth factors

A new human hepatocellular (HCC) cell line, HAK-3, was established from a resected HCC of a Japanese, female patient. HAK-3 retains morphologic features of the original HCC, and proliferates in a monolayered sheet (doubling time: 26 h). HAK-3 is a single aneuploid cell population with a DNA index of 2.42, the karyotype is human, chromosomes are 80-85 (mode: 83), and secretes fibronectin and tissue polypeptide antigen. Epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) dose-dependently accelerated the cell proliferation, while deletion-type hepatocyte growth factor (dHGF) tended to suppress the proliferation, and transforming growth factor (TGF)-alpha showed almost no influence. dHGF induced the decrease of cell adhesiveness, changed the cell morphology to spindle-shaped cells, increased cell movement, and showed chemotactic effects with the increase of its concentration gradient in cultures. HAK-3 would be useful in studies on the acceleration mechanisms of cancer cell proliferation by growth factors and of chemotaxis by dHGF.

High prevalance of TT virus infection in Japanese patients with liver diseases and in blood donors

BACKGROUND/AIMS

Although a novel DNA virus, TT virus (TTV), has been isolated from a patient with cryptogenic post-transfusion hepatitis, its pathogenic role remains unclear. To elucidate its prevalence and clinical impact in patients with liver diseases, the presence of TTV DNA was assessed in patients with liver diseases and blood donors (BDs) in Japan using two primer sets, one conventional and the other new and highly sensitive.

METHODS

We studied 261 samples, 72 with chronic hepatitis associated hepatitis C virus (HCV-CH), 57 with hepatocellular carcinoma associated HCV (HCV-HCC), 12 with HCC without either HCV or hepatitis B virus (NBNC-HCC), and 120 of BDs.

RESULTS

Using two primer sets, TTV DNA was detected in 68 (94.4%), 53 (93.0%), 12 (100%), and 98 (81.7%) HCV-CH, HCV-HCC, NBNC-HCC, and BDs, respectively. The prevalence was not significantly different between HCV-CH and HCV-HCC, or between HCV-HCC and NBNC-HCC. Comparison between patients with and without TTV revealed no significant differences in backgrounds or biochemical findings. Histopathological findings in patients with HCV-CH, and number, maximum diameter, and histological differentiation of HCC also did not demonstrate any relation to TTV infection. TTV strains can be divided into five groups using phylogenetic analysis, but no disease-specific group appears to exist.

CONCLUSIONS

Our data suggest that: 1) TTV is very prevalent among patients with liver diseases and even among BDs in Japan, 2) TTV infection does not impact on liver damage with HCV infection, and 3) TTV infection also does not affect the development or progression of HCC.

Interferon alfa receptor expression and growth inhibition by interferon alfa in human liver cancer cell lines

Type I interferon (IFN) receptor consists of two chains (Hu-IFN-alphaR1 and Hu-IFN-alphaR2), and Hu-IFN-alphaR2 takes a soluble (Hu-IFN-alphaR2a), short (Hu-IFN-alphaR2b), or long (Hu-IFN-alphaR2c) form. We examined the expression of type I IFN receptor, the growth-suppression effect of IFN-alpha, and their relationship in 13 liver cancer cell lines. With reverse-transcription polymerase chain reaction (RT-PCR) analysis, the expressions of Hu-IFN-alphaR1, Hu-IFN-alphaR2a, and Hu-IFN-alphaR2c were confirmed in all cell lines, and that of Hu-IFN-alphaR2b in 12 cell lines. All cell lines expressed mRNAs of a transcriptional activator, interferon regulatory factor (IRF)-1, and its antagonistic repressor (IRF-2). Flow cytometry revealed weak expression of Hu-IFN-alphaR2 on the cell surface in 12 cell lines. The soluble-form protein of Hu-IFN-alphaR2 was detected at varying levels in culture supernatants of all cell lines with enzyme-linked immunosorbent assay (ELISA). Cell proliferation was suppressed in proportion to the dose of human natural IFN-alpha at 96 hours of culture, but it was not clearly related to the expression of Hu-IFN-alphaR2 protein on the cell surface. Investigations on the morphology, DNA, and cell cycle presented four growth suppression patterns as a result of IFN-alpha: 1) induction of apoptosis and blockage of cell cycle at the S phase (9 cell lines); 2) blockage at the S phase (2 cell lines); 3) induction of apoptosis and blockage at the G2/M phase (1 cell line); and 4) blockage at the G1 phase (1 cell line). There was no evidence showing that changes in the expressions of Bcl-2, Bcl-xL, Bak, and Bax lead directly to IFN-alpha-mediated apoptosis. Our findings demonstrated that IFN-alpha would express growth-suppression effects at varying degrees by inducing inhibition of cell-cycle progression with or without apoptosis, regardless of the expression level of Hu-IFN-alphaR2 protein on the cell surface.

Expressions of epidermal growth factor family and its receptor in hepatocellular carcinoma cell lines: relationship to cell proliferation

In 6 HCC cell lines, clear expressions of EGFR and TGF-alpha were found in flow cytometry, while expressions of EGF, HB-EGF and AR were quite low. TGF-alpha secretion into culture supernatants became measurable when TPA 0.5 microM was added. TPA accelerated the proliferation of KYN-3 cells, and anti-TGF-alpha neutralizing antibody suppressed this proliferation in a dose-dependent manner. Addition of exogenous TGF-alpha, EGF, AR, or HB-EGF with heparin accelerated cell proliferation. In non-stimulated cultures, cell proliferation was suppressed by anti-EGFR neutralizing antibody, but not by the antibodies for EGF, TGF-alpha, AR and HB-EGF. HCC may possess a paracrine system regulated by these 4 ligands, and an autocrine system, under a certain condition, via TGF-alpha and EGFR.

Expression of cyclooxygenase-2 in human hepatocellular carcinoma: relevance to tumor dedifferentiation

Cyclooxygenase (COX) is a key enzyme in the synthesis of prostanoids. Two isoforms of this enzyme have been identified: COX-1 and COX-2. Recent studies have suggested that COX-2, but not COX-1, may play a role in colorectal tumorigenesis. In the present study, we investigated the expression of COX-2 as well as COX-1 in human hepatocellular carcinoma (HCC) tissues using immunohistochemistry and immunoblotting. Forty-four surgically resected HCC tissues with adjacent nontumorous livers (NTs), involving 17 cases of chronic viral hepatitis and 27 cases of cirrhosis, and 7 surgically resected, histologically normal liver tissues were used. The well-differentiated HCC expressed COX-2 more frequently and strongly than less-differentiated HCC or hepatocytes of NTs. Less-differentiated HCCs expressed less COX-2 than hepatocytes of NTs, which showed scattered, strong COX-2 expression. Histologically normal liver was weakly positive for COX-2. The expression of COX-1 was weaker than that of COX-2 in hepatic neoplastic and non-neoplastic parenchymal cells. An enhanced expression of COX-1 was not observed in well-differentiated HCCs. Immunoblotting also confirmed up-regulation of COX-2, but not COX-1, in well-differentiated HCCs. The present study is the first to demonstrate a high expression of COX-2 in well-differentiated HCC and a low expression in advanced HCC, in contrast to its continuous expression during colorectal carcinogenesis. These findings suggested that COX-2 may play a role in the early stages of hepatocarcinogenesis, but not in the advanced stages, and may consequently be related to HCC dedifferentiation.

Vascularization of small hepatocellular carcinomas: correlation with differentiation

BACKGROUND

Hepatocellular carcinoma (HCC) is generally considered a hypervascular tumor when visualized by angiography. However, small HCCs are not always found to be hypervascular.

METHODS

To evaluate this, 50 HCCs < or =3 cm in diameter were studied. The 50 tumors consisted of 16 well-differentiated HCCs, 25 moderately differentiated HCCs, and 9 that were each a mixture of well- and moderately differentiated HCC.

RESULTS

The mean number of portal tracts in the well-differentiated HCCs was 34% of the number in the surrounding nontumorous liver, and few intratumoral arterioles were seen. In contrast, the mean number of portal tracts in the moderately differentiated HCCs was 0.6% of the number in the surrounding nontumorous liver, and abundant intratumoral arterioles were seen. For HCCs that contained both well-differentiated and moderately differentiated tumor, the distribution of portal tracts and intratumoral arterioles in each portion was similar to that seen in well-differentiated or moderately differentiated HCC alone, respectively. HCCs that were larger than 1.5 cm in diameter had fewer portal tracts and more intratumoral arterioles than HCCs whose diameters were < or =1.5 cm.

CONCLUSIONS

As small HCCs increase in size and become increasingly dedifferentiated, the number of portal tracts apparently decreases and intratumoral arterioles develop. These findings may reflect changes in the hemodynamics as the HCC develops.

Evaluation of curability and prediction of prognosis after surgical treatment for hepatocellular carcinoma by lens culinaris agglutinin-reactive alpha-fetoprotein

The clinical significance of serum lens culinaris agglutinin-reactive alpha-fetoprotein (AFP-L3), which can distinguish between hepatocellular carcinoma and hepatitis by detecting a sugar chain micro heterogeneity, was evaluated for its possible ability to recognize previously undetectable residual tumors, and for increasing the accuracy of prognosis after surgical treatment for hepatocellular carcinoma. Serum lens culinaris agglutinin-reactive alpha-fetoprotein was measured pre- and post-operatively in 130 patients who underwent curative surgical treatment for hepatocellular carcinoma. The preoperative AFP-L3 positive rate was 35.4%. AFP-L3 remained positive postoperatively in 28 of the 46 preoperative AFP-L3 positive patients, and converted to positive in 4 of the 84 preoperative AFP-L3 negative patients. Regardless to preoperative AFP-L3, the postoperative AFP-L3 positive patients had a poorer recurrence-free rate (p<0.0001). The postoperative L3 positive patients had a high incidence of recurrence due to metastasis, but did not have recurrence due to multicentric origin. Multivariate analysis revealed that AFP-L3 (p<0.0001) was the most independently significant factor for predicting survival after surgery among several conventional prognostic factors. Thus, AFP-L3 is a valuable marker for evaluation of curability of surgical treatment and for improving the accuracy of prognosis.

An unusual hyperplastic hepatocellular nodule in a patient with hepatitis C virus-related liver cirrhosis

Recent advances in diagnostic imaging techniques have increased the likelihood of detecting novel nodular lesions of the liver. We report here a case of unusual hyperplastic hepatocellular tumor found in a 70-yr-old woman with hepatitis C virus-related cirrhosis. A mass was incidentally detected in the right lobe by abdominal ultrasonography and confirmed by computed axial tomography (CT). Magnetic resonance imaging demonstrated that the tumor had hyperintense signal with a small hypointense region in the center and a thin, hypointense rim on T1-weighted image and a hypointense signal on T2-weighted image. CT during hepatic arteriography showed that the tumor was hypodense with a central hyperdense region, whereas CT during arterial portography revealed that the tumor was isodense and surrounded by a thin circular hypodense band with a central hypodense region. These radiographic findings suggested a diagnosis of dysplastic nodule with malignant foci of hepatocellular carcinoma. The patient underwent tumor resection. Macroscopically, the tumor, 45 x 45 x 30 mm in size, was encapsulated and had a central stellate-like scar with radiating septa. Histological examination showed a hyperplastic hepatocellular tumor without cellular, nuclear or structural atypia. The central fibrous scar contained abundant small, artery-like and vein-like vessels, whereas there were no normal portal triads but rather several portal tract-like structures lacking bile ducts in the parenchyma of the tumor. Some of the portal tract-like structures were composed of artery-like and vein-like vessels, and the others possessed vein-like vessels only. There were no bile ducts in the tumor. The nontumorous liver tissue had evidence of macronodular cirrhosis. Finally, this tumor was regarded as an unusual type of hyperplastic hepatocellular nodule encountered in cirrhotic liver, characterized by the presence of central stellate-like fibrosis and the lack of bile ducts. Although the pathogenesis of the hyperplastic lesion is unclear, it may represent a focal regenerative hepatocellular response to localized circulatory disorder.

Angioarchitecture and blood circulation in focal nodular hyperplasia of the liver

BACKGROUND/AIMS

We sought to clarify important unresolved points regarding angioarchitecture and blood circulation in focal nodular hyperplasia.

METHODS

Twenty-nine surgically resected focal nodular hyperplasia lesions were examined histologically, immunohistochemically, and radiologically. In three autopsy cases, red- and blue-colored gelatin was injected into the hepatic artery and the portal vein, respectively, to demonstrate the vasculature in focal nodular hyperplasia.

RESULTS

Histologically, no orientation with respect to portal tracts and central veins was evident in any lesion. Within lesions, vessels were classified as: (i) anomalous arteries in the fibrous septa, (ii) capillaries in the fibrous septa, or (iii) venous vessels located mainly in the parenchyma. Vessels and sinusoids adjacent to fibrous septa were stained for CD 34 and von Willebrand factor. The anomalous arteries were connected to the capillaries. Capillaries in the fibrous septa were connected to sinusoids adjacent to fibrous septa. Venous vessels were connected to central or hepatic veins surrounding the lesions. Intranodular sinusoids were connected to the sinusoids in the surrounding normal liver. Red-colored gelatin, injected at autopsy into the hepatic artery, appeared not only in the anomalous arteries but also in capillaries and in sinusoids adjacent to the fibrous septa of the lesion. Angiography clearly depicted hepatic veins located near the lesions in nine cases. Computed tomography during arterial portography disclosed no portal blood flow in the lesions.

CONCLUSIONS

In focal nodular hyperplasia, arterial blood flows from the anomalous arteries via the capillaries into sinusoids adjacent to fibrous septa. The blood in the sinusoids drained to the hepatic vein either directly or via perinodular sinusoids.

Schwannoma of the liver: report of two surgical cases

Two surgical cases of benign schwannoma of the liver were examined: A 64-year-old female who was admitted to hospital for the treatment of early gastric cancer (case 1) and a 69-year-old female who had pitting edema in the legs (case 2). Diagnostic imaging revealed large solid masses located in the caudate lobe through to the left lobe of the liver in case 1 and in the left lobe in case 2. Both patients showed no signs of von Recklinghausen's disease. Partial hepatectomies were performed and the maximum diameter of their resected hepatic tumors was 4 cm and 15 cm, respectively. Histologically, the well-demarcated tumors were yellowish in color, elastic-hard in consistency and consisted predominantly of short spindle-shaped cells proliferating in an interlacing fashion. The tumor lesions were separated by fibrous bands and surrounded by a lymphoid cuff. Immunohistochemically, the tumor cells were positive for S-100 protein. The tumors were diagnosed as benign hepatic schwannoma.

Pathology of early hepatocellular carcinoma: progression from early to advanced

Small, early stage hepatocellular carcinoma (HCC) can be divided into 2 types; small nodular HCC with distinct margins and small HCC with indistinct margins. The latter consists of well-differentiated cancerous tissue with replacing growth at the boundary and with many portal tracts retained in the tumor. When these tumors reach approximately 1.5-2.0 cm in diameter, moderately or poorly differentiated cancer tissues develop within the well-differentiated cancer tissue and well-differentiated cancer tissues are replaced by less differentiated cancer tissues. This dedifferentiation seems to be closely related to tumor proliferation. When less differentiated cancer tissues within the well-differentiated cancer nodules proliferate in an expansive fashion, a "nodule in nodule" appearance is frequently identified. On the other hand, small nodular HCCs with distinct margins are well-defined, with more than half of them encapsulated by a thin fibrous capsule, and about 60% moderately differentiated. Tumor invasion into the portal vein and intrahepatic metastasis are found in 27% and 10%, respectively. Thus, although the size of the tumor may be small, some distinctly nodular small HCCs can already be interpreted as advanced cancers.

Expression of vascular endothelial growth factor in human hepatocellular carcinoma

Vascular endothelial growth factor (VEGF) is thought to take an important role in tumor angiogenesis. The present study examined VEGF expression immunohistochemically in hepatocellular carcinomas (HCCs) in various histological grades and sizes. In HCCs that were composed of cancerous tissues of single histological grade, VEGF expression was the highest in well-differentiated HCCs, followed by moderately differentiated HCCs, and then poorly differentiated HCCs. VEGF positivity gradually decreased with the increase in tumor size. In the nodules larger than 3.0 cm, 36.8% were VEGF-negative. In HCCs consisting of cancerous tissues of two different histological grades, the expression was less intensive in the higher-grade HCC component. VEGF was not expressed in sarcomatous areas, while VEGF was expressed in the surrounding HCC tissues. The expression was also remarkable in the noncancerous tissues in which inflammatory cell infiltration was apparent. VEGF expression was also examined in six HCC cell lines. In reverse-transcription polymerase chain reaction (RT-PCR) analysis, expressions of the two secretion types (VEGF121 and VEGF165) were the highest. Thus, VEGF protein in culture supernatant was measured by using enzyme-linked immunosorbent assay (ELISA) with or without inflammatory cytokines, i.e., interleukin (IL)-1beta, interferon (IFN)-alpha, IFN-gamma, and tumor necrosis factor (TNF)-alpha; and growth factors, i.e., epidermal growth factor (EGF), platelet-derived growth factor (PDGF)-BB, basic fibroblast growth factor (bFGF), and transforming growth factor (TGF)-alpha. As a result, secretion of VEGF from the cell lines was upregulated at various degrees. Based on these findings, VEGF expression in HCC tissues was thought to be related to the histological grade. The findings also indicate that various cytokines and growth factors could cooperatively act to enhance VEGF expressions in HCC.

Epidermoid cyst of the spleen with CA19-9 or carcinoembryonic antigen productions: report of three cases

True splenic cyst is a relatively rare disease, and the majority of the cases are classified as epidermoid cysts. Three cases of epidermoid cysts in the spleen or accessory spleen were studied using an immunohistochemical technique and staining for mucin. In case 1, serum carcinoembryonic antigen (CEA) and CA19-9, and in cases 2 and 3, serum CA19-9, before surgery were markedly elevated, and these levels decreased postoperatively. This strongly indicates the relationship between the increase of tumor marker levels and the presence of the epidermoid cyst. In addition, stratified squamous epithelium in the resected tissues of cases 1 and 2 was positive for anti-CEA antibody and anti-CA19-9 antibody, and that of case 3 was positive for anti-CA19-9 antibody. This strongly supports CEA or CA19-9 production in the squamous epithelium.

Immunohistochemical measurement of cell proliferation as replicative DNA synthesis in the liver of male Fischer 344 rats following a single exposure to nongenotoxic hepatocarcinogens and noncarcinogens

We aimed to modify an in vivo/in vitro hepatocyte replicative DNA synthesis (RDS) test using autoradiography of [3H]methylthymidine (3HTdR) into a nonradioactive in vivo version by applying 5-bromo-2'-deoxyuridine (BrdU) immunohistochemistry. The effects of 12 nongenotoxic hepatocarcinogens and 4 noncarcinogens on RDS induction and histological changes in the liver of male Fischer 344 (F344) rats were investigated 24 or 48 hrs after a single oral administration at diverse dose levels. A statistically significant, dose-related elevation in BrdU labeling indices (LI) was obtained for all of the 12 nongenotoxic hepatocarcinogens with only one exception of D,L-ethionine at relatively lower dose levels. No increase was observed in LI for any of the four noncarcinogens examined. From the results of histopathological evaluation, the increase in hepatocyte proliferation by carbon tetrachloride (CCl4), chloroform (CHCl3), and thioacetamide (TAA) was confirmed to be a regenerative liver response following cytotoxicity. Conversely, safrole, tannic acid, and urethane yet hepatotoxicants did not show inflammatory reaction or necrosis under the condition of the present study, and hence their mode of action by which they induce proliferative response was not obvious. The results of this study showed that the in vivo version of RDS test efficiently discriminated nongenotoxic hepatocarcinogens from noncarcinogens, while it did not well clarify the induction mode of cell proliferation.

alpha-Fetoprotein-producing rectal carcinoma--a case report

A case with an alpha-fetoprotein (AFP)-producing carcinoma originating from the rectum is described. A 71-year-old male patient, who underwent a rectectomy for rectal carcinoma, developed space occupying lesions in the liver and a remarkable AFP elevation (220,000 ng/ml) in the 6th month postoperatively, and then expired one year later. Histologically, the rectal carcinoma consisted of well-differentiated adenocarcinomas, and contiguous cancerous cells proliferating in either a medullary or trabecular pattern. In the "trabecular" areas, localization of AFP was confirmed immunohistochemically. Results of concanavalin A or lens culinaris agglutinin affinity chromatography demonstrated that it was between a hepatic type and a yolk sac type, and was considered to be an intestinal type. This could have been an AFP-producing rectal carcinoma, in which the patient experienced liver metastasis at a relatively early postoperative period and died. This shows that AFP-producing rectal carcinomas are highly malignant, biologically, similar to AFP-producing gastric cancers.

Clinicopathological study on hepatocellular carcinoma with lymphocytic infiltration

We examined the clinicopathologic features of 11 surgically resected hepatocellular carcinomas (HCCs) less than 3 cm in diameter with marked inflammatory cell infiltration (LHCCs). In comparison with the other 152 HCCs without such an infiltration (controls), there were no significant differences in male/female ratio, age, serum alpha-fetoprotein levels, and laboratory and imaging findings. All the 11 LHCC cases were hepatitis B surface antigen (HBsAg) negative and hepatitis C virus antibody positive. Among the 152 controls, 116 cases were also HBsAg negative and HCVAb positive and were referred to as HCV-only controls. The clinical features were not significantly different between the LHCC and the HCV-only controls. The LHCC group tended to have higher numbers of lymphocytes and monocytes in pre- and post-operative peripheral blood, but there were no significant group differences. Recurrence rate was 9.1% in the LHCC group, 47.7% in the controls and 47.5% in the HCV-only controls (P < .01). Five-year survival rate was 100% in the LHCC group, 65.1% in the controls and 68.1% in the HCV-only controls (P < .01). Histologically, remarkable inflammatory cell infiltration, mostly lymphocytic, was observed in the cancerous tissue of the LHCC group. Varying degrees of piecemeal necrosis of cancer nests produced by infiltrating lymphocytes were observed in all the 11 cases. Lymph follicle formation was also found in 10 of 11 cases (90.9%). Liver cirrhosis was associated in 6 LHCC cases (54.5%), in 117 control cases (77.0%), and in 91 HCV-only controls (78.4%). Tumor invasion into the portal vein in the vicinity of the tumor was found in 1 LHCC case (9.1%), in 54 controls (35.5%), and in 34 HCV-only controls (29.3%). Immunohistochemically, most of the infiltrating lymphocytes, other than those in the lymph follicle, were identified as T lymphocyte, and CD8+ T lymphocyte was more predominant than CD4+ T lymphocyte. Better prognosis of the LHCC group could attribute to the anti-tumor effect induced by cellular immunity of CD8+ and CD4+ T lymphocytes, and partly by humoral immunity of B cells which formed lymph follicles.

Clinicopathological study on hepatocellular carcinoma with lymphocytic infiltration

We examined the clinicopathologic features of 11 surgically resected hepatocellular carcinomas (HCCs) less than 3 cm in diameter with marked inflammatory cell infiltration (LHCCs). In comparison with the other 152 HCCs without such an infiltration (controls), there were no significant differences in male/female ratio, age, serum alpha-fetoprotein levels, and laboratory and imaging findings. All the 11 LHCC cases were hepatitis B surface antigen (HBsAg) negative and hepatitis C virus antibody positive. Among the 152 controls, 116 cases were also HBsAg negative and HCVAb positive and were referred to as HCV-only controls. The clinical features were not significantly different between the LHCC and the HCV-only controls. The LHCC group tended to have higher numbers of lymphocytes and monocytes in pre- and post-operative peripheral blood, but there were no significant group differences. Recurrence rate was 9.1% in the LHCC group, 47.7% in the controls and 47.5% in the HCV-only controls (P < .01). Five-year survival rate was 100% in the LHCC group, 65.1% in the controls and 68.1% in the HCV-only controls (P < .01). Histologically, remarkable inflammatory cell infiltration, mostly lymphocytic, was observed in the cancerous tissue of the LHCC group. Varying degrees of piecemeal necrosis of cancer nests produced by infiltrating lymphocytes were observed in all the 11 cases. Lymph follicle formation was also found in 10 of 11 cases (90.9%). Liver cirrhosis was associated in 6 LHCC cases (54.5%), in 117 control cases (77.0%), and in 91 HCV-only controls (78.4%). Tumor invasion into the portal vein in the vicinity of the tumor was found in 1 LHCC case (9.1%), in 54 controls (35.5%), and in 34 HCV-only controls (29.3%). Immunohistochemically, most of the infiltrating lymphocytes, other than those in the lymph follicle, were identified as T lymphocyte, and CD8+ T lymphocyte was more predominant than CD4+ T lymphocyte. Better prognosis of the LHCC group could attribute to the anti-tumor effect induced by cellular immunity of CD8+ and CD4+ T lymphocytes, and partly by humoral immunity of B cells which formed lymph follicles.

p53 overexpression in small hepatocellular carcinomas containing two different histologic grades

There is evidence to suggest that a focus of less-differentiated hepatocellular carcinoma (HCC) may arise within a pre-existing well-differentiated HCC, eventually replacing it. In the present study, the p53 tumor suppressor gene was analyzed by immunohistochemistry in 31 hepato-cellular carcinomas (HCCs) containing two or more regions in the same nodule with different histologic grades. p53 was overexpressed in the nucleus in 13 of 31 HCCs (42%), in seven of which p53 overexpression was seen only in the less-differentiated area of the tumor. This suggests that overexpression of presumed mutant p53 may have contributed to dedifferentiation during the development of HCC.

A new human hepatocellular carcinoma cell line (HAK-2) forms various structures in collagen gel matrices

We established a new human hepatocellular carcinoma (HCC) cell line, designated HAK-2, from a surgically resected HCC of a 57-yr-old Japanese man. The patient's tumor consisted of 5 different histological features in a single nodule: well-differentiated HCC with trabecular pattern; and moderately differentiated HCC with 4 different patterns (i.e., trabecular, pseudoglandular, solid, and scirrhous). Morphologically, HAK-2 cells on a plastic dish showed oval-shaped nuclei and large flat, polygonal eosinophilic cytoplasm and proliferated in a monolayered sheet with a population doubling time of 36.8 hours. Meanwhile, various structures, such as compact, trabecular, and tubular arrangements, were induced in HAK-2 cells cultured in type I collagen gel matrix. Also, HAK-2 cells in vitro underwent spontaneous apoptosis more frequently than other HCC cell lines examined. HAK-2 cells secreted various plasma proteins including albumin into the culture medium. Chromosome and flow cytometric analyses revealed that HAK-2 had many structural abnormalities with human karyotype and a single aneuploid cell population with a DNA index of 3.7, respectively. These findings suggest that HAK-2 is a new human HCC cell line representing two morphological characteristics; (1) formation of various structures in the presence of extracellular matrix and (2) frequent spontaneous apoptosis in vitro.

Pathology of chronic hepatitis C in children. Child Liver Study Group of Japan

Limited information is available regarding the histology of hepatitis C virus infection in children. The aim of this study was to determine the histological pattern of chronic hepatitis C (CHC) in children, and liver biopsy specimens from 109 pediatric patients with CHC were examined. Each biopsy specimen was evaluated based on a numerical scoring system for the stage of fibrosis (1-4), the grade of portal/periportal necroinflammation (0-4), the grade of lobular necroinflammation (0-4), and their sum (final grade). The histological lesions considered to be characteristic of chronic hepatitis were also evaluated. None of the children had liver cirrhosis, and 105 cases (97%) were stage 1 or 2. Only 4 children were stage 3. Two of these 4 cases showed hemosiderosis. A significant correlation was observed between the staging score and the final grade in the pediatric patients (r = .59; P < .0001). The histological characteristics of adult CHC, such as lymphoid aggregate, bile duct injury, and fatty changes, were also observed in the children. In conclusion, the majority of children with CHC presented with mild fibrosis, but a few showed CHC with lobular distortion and hemosiderosis. Frequent blood transfusion may aggravate hepatic lesions in pediatric CHC.