Hepatoblastoma: an immunohistochemical and ultrastructural study

Application of Bioelectrical Impedance Analysis in Nutritional Management of Patients with Chronic Kidney Disease

Body composition measurement plays an important role in the nutritional diagnosis and treatment of diseases. In the past 30 years, the detection of body composition based on bioelectrical impedance analysis (BIA) has been widely used and explored in a variety of diseases. With the development of technology, bioelectrical impedance analysis has gradually developed from single-frequency BIA (SF-BIA) to multi-frequency BIA (multi-frequency BIA, MF-BIA) and over a range of frequencies (bioimpedance spectroscopy, BIS). As the clinical significance of nutrition management in chronic kidney disease has gradually become prominent, body composition measurement by BIA has been favored by nephrologists and nutritionists. In the past 20 years, there have been many studies on the application of BIA in patients with CKD. This review describes and summarizes the latest research results of BIA in nutritional management of patients with CKD including pre-dialysis, hemodialysis, peritoneal dialysis and kidney transplantation, in order to provide reference for the application and research of BIA in nutritional management of chronic kidney disease in the future.

Histological and immunohistochemical study of hepatoblastoma: correlation with tumour behaviour and survival

Background

Hepatoblastoma (HB) has different histological subtypes, with varying prognosis. Though the survival has drastically improved, subsets of patients are not responsive to therapy. Therefore, it becomes important to determine the factors which affect the behaviour of the tumour. This study was aimed to look at the histopathological subtypes and compare with immunohistochemical (IHC) expression of CK19, beta-catenin and EpCAM and survival.

Methods

This study included 55 cases of HB. IHC expression of CK19, beta-catenin and EpCAM were correlated with histological subtypes, tumour behaviour, response to chemotherapy and survival.

Results

Most common epithelial subtype was fetal (43.2%) and mixed epithelial (54.8%) in pre- and post-chemotherapy groups respectively. Microvascular invasion (MVI) was present in 14/33 resected tumours. CK19 expression was seen in 54.2% and 72.2% of embryonal subtype, nuclear beta-catenin expression in 48.7% and 57.1% and EpCAM in 100% and 82.1% of tumours in pre- and post-chemotherapy groups, respectively. Fetal subtype had a lesser chance of MVI, recurrence, metastasis and death. Beta-catenin expression was associated with lower event free survival (EFS) and EpCAM with ≥50% viable tumour following chemotherapy (P=0.04). Age at diagnosis ≤2 years, male sex, alpha-fetoprotein <10,000 IU/mL following chemotherapy, solitary tumour (P=0.001), size ≤5 cm, pretreatment extent of disease (PRETEXT) I&II, mitosis ≤2/10 high power fields (hpf), viable tumour <50% (P=0.04) and absent nuclear expression of beta-catenin, predicted a higher EFS rate.

Conclusions

Beta-catenin expression is associated with lower EFS and EpCAM expression with tumour viability. Multifocality and viable tumour ≥50% were significant factors predicting lower EFS. These factors should be included in the prognostication of HBs.

Pathology of the liver in children: Where would I (we) be without "Pepper"?

A tribute to Pepper's lasting contributions to Hepatopathology.

A case of hepatoblastoma misdiagnosed as combined hepatocellular carcinoma and cholangiocarcinoma in an adult

Hepatoblastoma usually occurs in children under the age of 2 years, with very few cases reported in adults. We experienced a case of adult hepatoblastoma in a 36-year-old female with chronic hepatitis B. She had experienced sudden onset abdominal pain. Her serum alpha-fetoprotein level was markedly elevated, and abdominal CT showed a 9-cm mass with internal hemorrhage in the right hepatic lobe with hemoperitoneum, so an emergency hepatic central bisectionectomy was performed. The initial histologic examination revealed that the mass mimicked combined hepatocellular carcinoma and cholangiocarcinoma with spindle-cell metaplasia of the cholangiocarcinoma element. Follow-up abdominal CT performed 3 months later showed a 5.5-cm metastatic mass in the left subphrenic area. Laparoscopic splenectomy with mass excision was performed, and hepatoblastoma was confirmed histologically. A histologic re-examination of previously obtained surgical specimens also confirmed the presence of hepatoblastoma. Metastatic hepatoblastoma was found at multiple sites of the abdomen during follow-up, and so chemotherapy with cisplatin, 5-fluorouracil (5-FU), and vincristine was applied, followed by carboplatin and doxorubicin. Despite surgery and postoperative chemotherapy, she died 12 months after symptom onset.

Neuroendocrine differentiation in embryonal type hepatoblastoma

Hepatoblastoma, a malignant tumor which arises occasionally in older children but very rarely in adults, exhibits divergent differentiation with embryonal cells, fetal hepatocytes and immature elements. This report describes an embryonal type hepatoblastoma with neuroendocrine differentiation in a 16-year-old patient, which was diagnosed postoperatively. Clinical and radiologic work-up failed to reveal a primary gastrointestinal malignancy and no primary lesions were detected in any other organ. This feature of hepatoblastoma is considered to be a multidirectional differentiation of the small epithelial or stem cells of the liver. At 2-year follow up, the patient remains symptom-free, with normal laboratory and diagnostic imaging studies, and no recurrent or metastatic disease identified.

Hepatoblastoma in a cat

Hepatoblastomas are neoplasms that originate from putative pluripotential stem cells of the liver. A hepatic mass from an 8-year-old Abyssinian cat was composed of cords and sheets of neoplastic cells, with scattered rosettes and small ductal structures. Most neoplastic cells had a pale eosinophilic cytoplasm and a round to ovoid nucleus. The tumor also had short spindle cells with an oval nucleus. Immunohistochemically, neoplastic cells were weakly positive for embryonic hepatocellular markers, such as alpha-fetoprotein and cytokeratin (CK) 8/18, but negative for the hepatocellular marker Hepatocyte Paraffin 1. The cells were also positive for CD56/neural cell adhesion molecule and for the biliary epithelial markers CK 7, CK 8/18, CK CAM5.2, and vimentin, but negative for CK 20. Some neoplastic cells expressed neuroectodermal or neuroendocrine markers, such as protein gene product 9.5 and synaptophysin, but were negative for chromogranin A and not argyrophilic by the Grimelius technique. The cat died soon after the biopsy without clinical improvement.

Occurrence of hepatocellular carcinoma after hepatoblastoma resection in an adult with hepatitis C virus

Hepatoblastoma is a rare malignancy in adults. It is often diagnosed after the appearance of symptoms, therefore, the tumor size tends to be larger. In patients with no indication for a hepatic resection, the prognosis of adult hepatoblastoma is quite poor. A 54-year-old man with hepatitis C virus-associated liver cirrhosis was initially treated with a hepatic resection for a hepatic tumor, 3 cm in diameter. The tumor consisted of osteoid-like and cartilaginous foci, myxomatous stroma, and poorly differentiated hepatocellular carcinomatous cells and was diagnosed as a mixed epithelial and mesenchymal hepatoblastoma. Two years after the first operation, multicentric hepatocellular carcinomas developed in the remnant liver and were successfully treated with a secondary hepatic resection combined with radio-frequency ablation. The patient is now alive with no recurrence at 5 years after the initial hepatectomy. To the best of our knowledge, the primary hepatoblastoma was the smallest such tumor reported and this is the first report of a metachronous hepatoblastoma and hepatocellular carcinoma in an adult hepatitis patient.

Molecular mapping of human hepatocellular carcinoma provides deeper biological insight from genomic data

DNA microarray analysis of human cancer has resulted in considerable accumulation of global gene profiles. However, extraction and understanding the underlying biology of cancer progression remains a significant challenge. This study applied a novel integrative computational and analytical approach to this challenge in human hepatocellular carcinoma (HCC) with the aim of identifying potential molecular markers or novel therapeutic targets. We analysed 100 HCC tissue samples by human 30K DNA microarray. The gene expression data were uploaded into the network analysis tool, and the biological networks were displayed graphically. We identified several activated 'hotspot' regions harbouring a concentration of upregulated genes. Several 'hotspot' regions revealed integrin and Akt/NF-kappaB signalling. We identified key members linked to these signalling pathways including osteopontin (SPP1), glypican-3 (GPC3), annexin 2 (ANXA2), S100A10 and vimentin (VIM). Our integrative approach should significantly enhance the power of microarray data in identifying novel potential targets in human cancer.

Expression of glypican 3 in hepatoblastoma: an immunohistochemical study of 65 cases

Glypican 3 is a heparin sulfate proteoglycan bound to the cell surface that is theorized to participate in cell signaling, resulting in embryonic cell growth and differentiation. The GPC3 gene is mutated in Simpson-Golabi-Behmel syndrome, whose features include numerous developmental abnormalities, tissue overgrowth, and an increased risk for embryonal malignancies, including hepatoblastoma. GPC3 has been detected in hepatic stem cells and was recently identified as one of the most overexpressed genes in hepatoblastoma by microarray analysis. The purpose of this study was to analyze the expression of GPC3 in a large series of hepatoblastoma using immunohistochemistry to assess its use as a diagnostic marker. The GPC3 immunoreactivity was semiquantitatively evaluated in 65 cases of hepatoblastoma. In addition, histologic patterns in each tumor were individually assessed for immunoreactivity. All 65 hepatoblastomas had cytoplasmic immunoreactivity for GPC3 with greater than 90% of cases showing strong, diffuse positivity. There was no reactivity in benign liver tissue. Fetal, embryonal, and small cell undifferentiated patterns were diffusely positive in almost all cases, whereas mesenchymal and teratoid patterns were nearly all negative. The high GPC3 expression consistently demonstrated in this study suggests that GPC3 may play a role in the tumorigenesis of hepatoblastoma.

Evaluation of gene expression related to hepatic cell maturation and differentiation in a chemically induced mouse hepatoblastoma cell line

The MHB-2 cell line, established from a mouse hepatoblastoma (HB), was subjected to the reverse transcriptase-polymerase chain reaction (RT-PCR) for evaluation of gene expression related to cell differentiation. RNAs for c-kit, CD34, thy-1, albumin, cytokeratin (CK) 8, 18 and 19 could be detected, but expression of alpha-fetoprotein, glucose-6-phosphatase, tyrosine aminotransferase and CK7 was not observed. MHB-2 cells were positive for CK8/18 but negative for c-kit, CD34, thy-1 and albumin on protein level. Immunohistochemical staining of the HB in vivo revealed diffusely expressed c-kit. Thy-1-positive HB cells were sparsely observed, but the tumor was negative for CD34 and rarely positive for CK8/18. By in situ hybridization, the HB was positive for CK18 but negative for CK19. Slight expression of albumin, but the lack of immature hepatocytic marker suggested some heterogeneous hepatocyte or an undifferentiated cell from other origin. Furthermore, positive expression of CK19 as well as CK8 and CK18 in culture strongly suggested the differentiation into a biliary lineage or the bidirectional state. In conclusion, the present study indicated the mouse HB to have de-differentiated, bipotent, or biliary-like cell characteristics, and considering the histological difference between HB and biliary tumors, it suggests the mouse HB cells are closely like some sort of hepatic undifferentiated cells.

Hepatoblastomas and liver development: a study of cytokeratin immunoexpression in twenty-nine hepatoblastomas

Hepatoblastomas (HBs) recapitulate liver development. It is possible that HBs result from malignant transformation of hepatic precursor cells, and they may reflect a blockage in normal development. Here we study the expression of cytokeratins (CKs) in order to delineate the immunoprofile and relationship with liver development, as well as vimentin and alphafetoprotein (AFP), of HBs. Immunohistochemistry was performed in a tissue microarray (TMA) containing representative areas of 18 HBs (fetal and/or embryonal and/or mesenchymal); we also reviewed 11 cases not included in the TMA. No cases stained for CKs 1, 5/6, 7, 10, 13, 15, 16, 20, and 34betaE12. CK8 stained 73.07% of fetal, 50% of embryonal, and 18% of mesenchymal areas. CK18 stained 100% of epithelial areas. CK19 staining was intense and diffuse in 100% of embryonal samples, but it was weaker in fetal areas (66.66%). AE1 stained epithelial areas in all cases, and it stained 29.41% of mesenchymal areas. AE3 stained 84.61% of embryonal and 60% of fetal components. AE1/AE3 showed stronger staining in embryonal (100%) than in fetal areas (76.92%). Vimentin staining was strong in embryonal (66.66%) and mesenchymal (84.61%) components but weak in fetal areas (8%). Alphafetoprotein was positive in only 20% of fetal and 70% of embryonal areas. Our results support the hypothesis that immunoexpression of HBs follows the stages of normal liver development. Embryonal areas look less differentiated, expressing vimentin and biliary epithelium CKs, whereas fetal areas display a more developed phenotype, similar to that of mature hepatocytes. These data aid in understanding the ontogenesis of HBs and may be used in histopathological diagnosis.

Stem-like cells in human hepatoblastoma

Hepatoblastoma is a pediatric liver tumor with epithelial components resembling embryonal and fetal liver cells. The existence of teratoid hepatoblastoma suggests the presence of stem cells in hepatoblastoma. The aim of this study was to analyze the expression of stem cell markers in hepatoblastomas. We studied specimens from 10 hepatoblastomas. Five of the hepatoblastomas were of epithelial and five of mixed type. Immunohistochemistry (IHC) for the stem cell markers CD34, Thy1, c-kit, and the hepatic or biliary lineage markers CK-18, OCH, CK-7, and CD56 was performed. Double IHC for stem cell and lineage markers was used to identify putative liver stem cells. The different markers showed distinct distributions on the tumor cells. Cells in atypical ducts were found to express simultaneously stem cell markers and hepatocytic or biliary lineage markers. Other cells in connective tissue showed c-kit expression, but not hepatic or biliary marker expression. The data show the presence of different cell populations bearing stem cell markers in human hepatoblastoma. Ductal cells co-expressing stem cell markers and hepatic lineage markers phenotypically resemble hepatic stem-like cells. These findings support the thesis that stem cells play a role in the histogenesis of hepatoblastoma.

Germ cell tumor-like neoplasms occurring outside the anatomic midline

Most germ cell tumors occur in the gonads or in extragonadal sites in the anatomic midline; this article reviews tumors with similar or identical histologic features that arise in other topographic locations. Such lesions often represent the presence of "germ cell-like" or "germinal" components in what is otherwise recognized as a somatic neoplasm; however, they may also occur in pure form. The morphologic and immunohistochemical features of these proliferations are reviewed, according to the types of germ cell tumors that they recapitulate.

Comparative genomic hybridization analysis of hepatoblastoma reveals high frequency of X-chromosome gains and similarities between epithelial and stromal components

Hepatoblastoma (HB) is the most common liver tumor in childhood and differs in its environmental risk factors and genetic background from hepatocellular carcinoma. HB is associated with inherited conditions such as familial adenomatous polyposis and Beckwith-Wiedemann syndrome, suggesting the importance of genetic abnormalities in the pathogenesis and progression of this disease. It has a very polymorphous morphology. A diverse range of cytogenetic alterations has been reported to date, the most frequent being trisomy 2 and trisomy 20. Thirty-five HB specimens from 31 patients (22 purely epithelial, 4 purely mesenchymal, 9 mixed) were examined by comparative genomic hybridization (CGH), a technique that enables us to screen the entire tumor genome for genetic losses and gains. Our aims were as follows: (1) to characterize chromosome abnormalities that appear in this tumor and (2) to identify possible differences between different histologic subtypes of HB. We found significant gains of genetic material, with very little difference in the number and type of alterations between the different histologic components of HB. The most frequent alterations were gains of Xp (15 cases, 43%) and Xq (21 cases, 60%). This finding was also confirmed by fluorescent in situ hybridization performed on nuclei extracted from 6 specimens. Other common alterations were 1p-, 2q+, 2q-, 4q-, and 4q+. We found no difference between different histologic subtypes, a finding that may be in agreement with the hypothesis of a common clonal origin for the different components. An hitherto-unreported high frequency of X chromosome gains may support the assumption that X-linked genes are involved in the development of this neoplasm.

Stem-like cells in hepatoblastoma

BACKGROUND

The principles of tumor biology suggest that hepatoblastoma is derived from a pluripotent stem cell. Our studies were undertaken to investigate this tumor for the presence of cells with morphologic and immunophenotypic features of the oval cells of rodents that are thought to be closely related to hepatic stem cells.

PROCEDURE

Hepatoblastomas of various subtypes were investigated by electron microscopy and immunoelectron microscopy with antibodies against cytokeratin 7, in the liver a marker of biliary differentiation, and albumin, a marker of hepatocytic differentiation. Immunohistochemical investigations were performed with the antibodies OV-1 and OV-6, which recognize antigens associated with oval cells.

RESULTS

OV-1 stained scattered cells in seven of 12 tumors investigated and OV-6 in nine. Small epithelial cells (SEC) with the ultrastructural features of the oval cells were found by electron microscopy. They were characterized by small size (7-18 microm), often an oval shape, tonofilament bundles, and tight junctions or desmosome-like junctions. SEC were found in small numbers in areas of fetal differentiation and in moderate numbers in areas of embryonal differentiation. In small cell hepatoblastoma, nearly all the tumor cells exhibited SEC-like features. Immunoelectron microscopy revealed coexpression of cytokeratin 7 and albumin by SEC.

CONCLUSIONS

SEC with ultrastructural and immunophenotypic features exhibited by oval cells, i.e., hepatic stem-like cells, are found in hepatoblastoma. Their numbers vary with the differing degrees of differentiation seen in the various subtypes. The findings further support the hypothesis that hepatoblastoma is derived from a pluripotent stem cell.

Pediatric liver tumors and hepatic ontogenesis: common and distinctive pathways

Several types of pediatric liver tumors exhibit structural features apparently reflecting processes which normally occur during hepatic ontogenesis: some hepatoblastomas mimic distinct phases of hepatogenesis, including the formation of mesenchymal structures closely associated with immature epithelia, and there are tumors almost exclusively consisting of complex mesenchymal patterns. Current classifications of hepatoblastomas refer to the identification of more or less mature (differentiated) single or mixed components seen in histologic preparations. These do not, however, attempt to integrate ontogenic pathways, in contrast for example, to nephroblastoma and associated lesions, where such a view has proved to be highly fruitful. Based on the fact that an enormous amount of knowledge has recently been accumulated regarding hepatic ontogenesis, time may have come to look at these tumors with a new eye. In what follows, we aim at trying to analyze distinct features of pediatric hepatic tumors (except vascular tumors) within the background of ontogenesis. Some key steps of hepatogenesis and the regulatory factors involved may, in the future, deliver an armamentarium to search for novel molecular mechanisms involved in tumorigenic pathways.

The role of immunohistochemistry in diagnosis

Immunohistochemistry is a strong tool in hepatopathologic diagnosis: the technique is relatively simple and inexpensive. New and very sensitive detection methods have been recently developed (e.g., the EnVision technique and the microwave antigen retrieval method). This article discusses the role of immunohistochemistry in differentiating chronic cholestatic diseases from chronic hepatitis and in characterizing infectious agents. Algorythms for the typing of lymphomas and for the differentiation of primary tumors versus metastases are proposed as well. The immunohistochemical criteria for the diagnosis of premalignant lesions are discussed.

Small cell undifferentiated histology in hepatoblastoma may be unfavorable

BACKGROUND

Chemotherapy has improved the prognosis of hepatoblastoma demonstrably. It renders seemingly unresectable primary tumors amenable to surgery and can cure metastases. Some authors advocate preoperative chemotherapy for patients with tumors that are deemed resectable, relying solely on percutaneous biopsy or even on diagnostic imaging and elevated serum alpha-fetoprotein levels for diagnosis. However, certain cytologic features of hepatoblastoma appear to have important prognostic consequences. Well differentiated fetal hepatoblastomas that are confined to the liver and that have minimal mitotic activity may not require additional therapy if they are resected totally.

METHODS

In the current study 16 completely resected hepatoblastomas that exhibited partial or predominant small cell undifferentiated histology were identified retrospectively and correlated with patient outcome.

RESULTS

Ten of 16 patients with completely resected tumors exhibiting small cell undifferentiated histology developed a disease recurrence. Five of these recurrences were fatal.

CONCLUSIONS

Small cell undifferentiated histology may have an unfavorable effect on outcome in patients with completely resected hepatoblastoma. The focal distribution of small cell histology in the majority of these tumors suggests that treating hepatoblastoma based on limited preexcision biopsies may deprive some patients of appropriate therapy.

Hepatic stem cells: a review

The existence of a liver stem cell population has only gained credence recently, following the results of animal experiments. These cells are thought to reside in the terminal bile ductules (canals of Hering). Hepatocyte division is responsible for liver regeneration after most causes of injury. However, stem cells may contribute to hepatocyte regeneration, or even take over this role if the liver injury is severe and associated with an impairment of hepatocyte proliferation as in cirrhosis or submassive/massive necrosis, due to drugs, toxins or viruses. "Oval" cells are the descendants of the stem cells and are found in the portal and periportal regions in experimental animals within days of the liver injury. These cells proliferate to form narrow ductules, which may stain positively for biliary cytokeratins CK 19, and radiate out into the damaged parenchyma. Both in vitro and in vivo animal studies now suggest that oval cells can differentiate into bile ductular cells or hepatocytes to allow repopulation of the injured liver. As the oval cells differentiate into hepatocytes they may show positive staining for pyruvate kinase isoenzyme L-PK, albumin and alpha-fetoprotein. There is also growing evidence that bone marrow stem cells may contribute to liver regeneration. The possible involvement of hepatic stem cells in the development of dysplastic nodules, hepatocellular carcinoma and cholangiocarcinoma has been suggested but remains highly controversial. Oval cell isolation and culture techniques, together with stem cell transplantation strategies, may in the future provide novel treatments for individuals with inherited and acquired hepatic disorders.

Immunohistochemical characterization of hepatoblastomas in B6C3F1 mice treated with diethylnitrosamine and sodium phenobarbital

Hepatoblastomas (HBs) were induced in B6C3F1 male mice by diethylnitrosamine (DEN) and sodium phenobarbital (PB). Six-week-old mice received a single intraperitoneal dose of DEN followed by a continuous treatment with PB in diet at a concentration of 0 (group 1) or 500 (group 2) ppm for 50 weeks. HBs were observed in 13 of 21 (62%) group 2 mice, with typical histologic features as reported previously, while no such tumors were observed in group 1. Seven of 13 (54%) HBs were found in and/or adjacent to hepatocellular adenomas (HCAs) or hepatocellular carcinomas (HCCs). Immunohistochemically, all HBs were positive for S-100 protein but negative for keratin, alpha-fetoprotein (AFP), albumin (ALB) and vimentin, while HCC cells occasionally reacted positively for AFP with a mosaic pattern. HCC and HCA cells were occasionally positive for ALB. Non-neoplastic hepatocytes and normal bile ducts were positively stained for ALB and keratin/S-100 protein, respectively. S-100 protein is known to be expressed in many mesenchymal tissues and neoplasms including neuroectodermal elements but negative in cells of the hepatic lineage. Thus, the present immunohistochemical results suggested that mesenchymal differentiation occurs in mouse HB cells as observed in human HBs, one of the most frequent infant liver tumors in humans. Although the susceptibility of mouse HBs to PB-promotion suggests a hepatocytic histogenesis, the present immunohistochemical results support the hypothesis that the mouse HB is derived from pluripotent endodermal stem-like cells.

Inhibition by an angiogenesis inhibitor, TNP-470, of the growth of a human hepatoblastoma heterotransplanted into nude mice

BACKGROUND/PURPOSE

The effect of TNP-470, an angiogenesis inhibitor, on the growth of a hepatoblastoma transplanted into nude mice was examined.

METHODS

A hepatoblastoma obtained from a 3-year-old girl was serially transplanted into nude mice subcutaneously, and the transplant tumors of the seventh and eighth generations were used for experiments. Expression of various markers in the tumors was examined immunohistochemically. TNP-470 was injected subcutaneously every other day into tumor-bearing mice from 3 weeks after tumor transplantation. The proliferation of tumor cells and endothelial cells was estimated by means of the bromodeoxyuridine labeling index.

RESULTS

The original hepatoblastoma showed the histology of the epithelial type, consisting of both the fetal and embryonal subtypes and was positively stained with anti-alpha-fetoprotein (AFP), anti-cytokeratin-19 and polyclonal anticarcinoembryonic antigen antibodies, and an antihuman hepatocyte antibody (hepatocyte paraffin 1). The transplant tumors consisted of solid nests of tumor cells with numerous vascular lakes of various sizes, and showed positive staining with all antibodies that reacted positively with the original hepatoblastoma. Injections of TNP-470 at the doses of 15 mg and 30 mg/kg body weight suppressed the tumor growth and the increase in the serum level of AFP dose dependently. Injections of TNP-470 also suppressed the proliferation of tumor cells and endothelial cells in the tumors.

CONCLUSIONS

Hepatoblastomas maintained in nude mice retained the immunohistochemical characteristics of the original hepatoblastoma, and TNP-470 suppressed the growth of hepatoblastomas transplanted into nude mice. TNP-470 may be worth investigating further as to its usefulness as a therapy for hepatoblastomas.

Two-year toxicity and carcinogenicity study of methyleugenol in F344/N rats and B6C3F(1) mice

Methyleugenol (MEG) was tested for toxicity/carcinogenicity in a 2-yr carcinogenesis bioassay because of its widespread use in a variety of foods, beverages, and cosmetics as well as its structural resemblance to the known carcinogen safrole. F344/N rats and B6C3F(1) mice (50 animals/sex/dose group) were given MEG suspended in 0.5% methylcellulose by gavage at doses of 37, 75, or 150 mg/kg/day for 2 yr. Control groups (60 rats/sex and 50 mice/sex) received only the vehicle. A stop-exposure group of 60 rats/sex received 300 mg/kg/day by gavage for 53 weeks followed by the vehicle only for the remaining 52 weeks of the study. A special study group (10 animals/sex/species/dose group) were used for toxicokinetic studies. All male rats given 150 and 300 mg/kg/day died before the end of the study; survival of female rats given 150 mg/kg/day and all treated female mice was decreased. Mean body weights of treated male and female rats and mice were decreased when compared to control. Area under the curve results indicated that greater than dose proportional increases in plasma MEG occurred for male 150 and 300 mg/kg/day group rats (6 and 12 month) and male 150 mg/kg/day mice (12 month). Target organs included the liver, glandular stomach, forestomach (female rats) and kidney, mammary gland, and subcutaneous tissue (male rats). Liver neoplasms occurred in all dose groups of rats and mice and included hepatoadenoma, hepatocarcinoma, hepatocholangioma (rats only), hepatocholangiocarcinoma, and hepatoblastoma (mice only). Nonneoplastic liver lesions included eosinophilic and mixed cell foci (rats only), hypertrophy, oval cell hyperplasia, cystic degeneration (rats only), and bile duct hyperplasia. Mice also exhibited necrosis, hematopoietic cell proliferation, and hemosiderin pigmentation. Glandular stomach lesions in rats and mice included benign and malignant neuroendocrine tumors, neuroendocrine cell hyperplasia, and atrophy and in mice included glandular ectasia/chronic active inflammation. In female rats, the forestomach showed a positive trend in the incidences of squamous cell papilloma or carcinoma (combined). Male rats also exhibited kidney (renal tubule hyperplasia, nephropathy, and adenomacarcinoma), mammary gland (fibroadenoma), and subcutaneous tissue (fibroma, fibrosarcoma) lesions. Male rats also exhibited malignant mesotheliomas and splenic fibrosis. These data demonstrate that MEG is a multisite, multispecies carcinogen.

Liver transplantation and chemotherapy for hepatoblastoma and hepatocellular cancer in childhood and adolescence

OBJECTIVE

To describe our experience with total hepatectomy and liver transplantation as treatment for primary hepatoblastoma (HBL) and hepatocellular carcinoma (HCC) in children.

STUDY DESIGN

A retrospective analysis of the perioperative course of 31 children with unresectable primary HBL (n = 12) and HCC (n = 19) who underwent transplantation between May 1989 and December 1998. Systemic (n = 18) and intraarterial (n = 7) neoadjuvant chemotherapy were administered; follow-up ranged from 1 to 185 months.

RESULTS

For HBL, 1-year, 3-year, and 5-year posttransplantation survival rates were 92%, 92%, and 83%, respectively. Intravenous invasion, positive hilar lymph nodes, and contiguous spread did not have a significant adverse effect on outcome; distant metastasis was responsible for 2 deaths. Intraarterial chemotherapy was effective in all patients treated. For HCC, the overall 1-year, 3-year, and 5-year disease-free survival rates were 79%, 68%, and 63%, respectively. Vascular invasion, distant metastases, lymph node involvement, tumor size, and gender were significant risk factors for recurrence. Intraarterial chemotherapy was effective in 1 of 3 patients. Six patients died of recurrent HCC, and 3 deaths were unrelated to recurrent tumor.

CONCLUSION

Liver transplantation for unresectable HBL and HCC can be curative. Risk factors for recurrence were significant only for HCC, with more advanced stages amenable to cure in the HBL group.

Congenital primitive epithelial tumor of the liver showing focal rhabdoid features, placental involvement, and clinical features mimicking multifocal hemangioma or stage 4S neuroblastoma

We describe an unusual case of congenital primitive epithelial tumor of the liver with focal rhabdoid features. The present case is unique and informative in the following aspects: (1) a first case of congenital epithelial tumor of the liver with no hepatocytic differentiation but focal rhabdoid features, (2) clinical similarities to multicentric hemangioma or stage 4S neuroblastoma, (3) diagnosis obtained from histological examination of the placenta immediately after birth.

Paclitaxel: an effective antineoplastic agent in the treatment of xenotransplanted hepatoblastoma

BACKGROUND

Hepatoblastoma is an uncommon liver tumor of infancy and early childhood. Though most patients with nonmetastatic hepatoblastomas can be cured by defining surgical strategies and chemotherapy regimes, new drugs are needed for children with advanced hepatoblastomas. The activity of paclitaxel as a new antineoplastic agent with limited experience in pediatric oncology was studied in a xenograft model.

PROCEDURE

Hepatoblastoma cell suspensions from three children were transplanted subcutaneously into nude mice NMRI (nu/nu). One of the primary tumors was an embryonal multifocal hepatoblastoma, whereas the other tumors were embryonal/fetal hepatoblastomas localized on a liver lobe. After 4 weeks, xenografted tumor sizes reached 50-100 mm3. The xenografted tumors resembled their originals histologically and produced high levels of alpha-fetoprotein. The efficiency of paclitaxel at equitoxic doses was analyzed.

RESULTS

Paclitaxel produced an effect in all three hepatoblastomas. There was a significant reduction of tumor volume (P < 0.001) and alpha-fetoprotein levels after chemotherapy (P < 0.0001). The proliferation activity of the tumor cells corresponded with these results. Histologically, after treatment with paclitaxel the tumor regression was 35%-49%. The mechanism of paclitaxel action could be demonstrated by light microscopy immunohistochemistry and electron microscopy.

CONCLUSIONS

The preliminary results in phase I trials of solid tumors in children and the results of this study suggest that paclitaxel in phase II studies can now be entertained for patients with hepatoblastoma.

Comparative activity of cisplatin, ifosfamide, doxorubicin, carboplatin, and etoposide in heterotransplanted hepatoblastoma

BACKGROUND

Hepatoblastoma is the most common primary malignant liver tumor affecting infants and young children. Recent clinical experience with advanced hepatoblastoma shows that a reliable in vivo model to study the tumor's response to drugs is needed urgently.

METHODS

Hepatoblastoma cell suspensions from three children were transplanted subcutaneously into NMRI nude mice (nu/nu). One of the primary tumors was a embryonal multifocal hepatoblastoma, whereas the other tumors were embryonal/fetal hepatoblastomas localized to one liver lobe. The xenograft tumors resembled their original tumors histologically and produced high levels of alpha-fetoprotein. The mice who received the tumors were given ifosfamide, cisplatin, doxorubicin, carboplatin, and etoposide as single agents. Thereafter, the tumor growth rate and alpha-fetoprotein levels in the animal sera were measured before and after chemotherapy and compared with the control group. After chemotherapy, the tumors were studied by conventional histology.

RESULTS

The tumors in the nude mice derived from the multifocal hepatoblastoma reacted minimally against four of the five cytotoxic agents, whereas cisplatin reduced the tumor volume significantly. There was a marked reduction in tumor volume in the other tumors after application of cisplatin and doxorubicin, respectively. The tumors displayed a moderate reduction in size after treatment with ifosfamide, etoposide, and carboplatin. The responses to the different cytostatic agents also corresponded with serum alpha-fetoprotein levels and mitotic rates in the tumor cells.

CONCLUSIONS

To the authors' knowledge, this is the first time an in vivo model for analyzing the effects of chemotherapy on hepatoblastoma has been established. The animal model may be suited for the evaluation of new drugs for the treatment of hepatoblastoma and for the investigation of multidrug resistance mechanisms in hepatoblastoma.

Expression of transforming growth factor-alpha in hepatoblastoma

BACKGROUND

Transforming growth factor-alpha (TGF-alpha) is a potent stimulator of cell proliferation in the liver and in liver tumors; however, its significance and association with hepatocyte proliferation remains unclear.

METHODS

Expression of TGF-alpha and proliferation markers, such as proliferating cell nuclear antigen (PCNA) and cyclin A, were studied and correlated with each other in samples of tumor and surrounding liver tissue taken from nine patients with hepatoblastoma. An avidin-biotin-peroxidase immunohistochemical method was used for detection of TGF-alpha, PCNA, and cyclin A, and in situ hybridization was used to detect TGF-alpha mRNA.

RESULTS

Two types of tumor cells of epithelial origin were distinguished based on the expression of TGF-alpha protein and RNA. The more differentiated "fetal" phenotype had a high expression of TGF-alpha and correlated with a low expression of proliferation markers. The less differentiated "embryonal" phenotype had low TGF-alpha expression and high proliferation activity.

CONCLUSIONS

The expression of TGF-alpha is associated with a certain morphologic phenotype of tumor cells in hepatoblastoma; higher expression can be detected in more differentiated tumor cells. The negative correlation between the expression of TGF-alpha and proliferation markers suggests that the less differentiated embryonal cells do not depend on growth stimulation provided by TGF-alpha.

Hepatoblastoma: DNA nuclear content, proliferative indices, and pathology

Hepatoblastoma (HB) is the most frequent malignant liver tumor in infancy, and both its biological features and its prognostic behavior are still under investigation. DNA content and proliferative activity of the tumor have been considered as biological parameters related to the tumor's aggressiveness. The present study attempts to investigate the possible association between histologic subtype, DNA content, and proliferative indices in HB. DNA content and the proportion of cells in the S-phase were assessed by flow cytometry in 34 cases of HB (14 prior to chemotherapy, 20 after chemotherapy), using formalin-fixed, paraffin-embedded archival samples. The proliferative cell nuclear antigen (PCNA) labeling index was also evaluated by immunohistochemistry, and both the flow cytometry (FC) and the immunohistochemical data were correlated with tumor pathology. A significant association was found between histological type, DNA content and the percentage of cells in the S-phase, with aneuploidy and the highest proportions of S-phase cells significantly associated with embryonal tumors. The PCNA labeling index was found to be significantly higher in embryonal than in fetal phenotype. The biological heterogeneity of HB is Confirmed by the different nuclear content of the fetal (diploid) and embryonal (aneuploid) epithelial components of the tumor, also ruling out the likelihood of fetal (diploid) clones deriving from the embryonal (aneuploid) neoplastic cells. Since the highly proliferative neoplastic clones (i.e., embryonal) are thought to be more sensitive to antimitotic drugs, further studies are indicated to determine the relationship between ploidy, proliferative indices and chemoresponsiveness.

Hepatoblastoma in a dog

A hepatoblastoma was found in a 13-year-old female Maltese dog. Histologically, the tumor showed a wide trabecular pattern and was frequently accompanied with vascular lake formation. Tumor cells were positive for cytokeratin and neuron specific enolase, but negative for chromogranin. Electronmicroscopically, tumor cells were accompanied with continuous basement membrane and had poorly developed desmosomes. Sinusoidal endothelia had fenestration and were surrounded by myofibroblast-like cells. To the best of our knowledge, this paper is the first report of morphological studies on canine hepatoblastoma.

A comparison of methods for heat-mediated antigen retrieval for immunoelectron microscopy: demonstration of cytokeratin No. 18 in normal and neoplastic hepatocytes

Postembedding antigen retrieval is a well established technique for immunoelectron microscopy; however, many antigens cannot be detected without additional unmasking procedures. This study was undertaken to determine whether microwave oven heating, autoclaving, and pressurized boiling, which are well recognized methods of antigen retrieval for light microscopy, and simple boiling can also be used in electron microscopy. We investigated neoplastic and normal hepatocytes using a commercially available mouse monoclonal antibody against cytokeratin NO. 18 (CK 18). The tissue was fixed in paraformaldehyde/glutaraldehyde and embedded in Lowicryl K4M at -40 C. Ultrathin sections in various buffers were exposed to heat using one of four methods or to pronase at 37 C before incubation with the primary antibody. The secondary antibody was gold-labeled goat anti-mouse antibody. Sections that were not heat-treated remained unlabeled, but heat-treated sections showed immunoreactivity located mainly at the cytoplasmic periphery. Some of the gold particles lay in direct or loose association with intermediate filaments, some were seen in the area of desmosomes, and some did not appear related to any structures. No difference in immunostaining was found among the four methods of heat treatment. The citrate buffer, pH 6.0, and 10 mM EDTA, pH 8.0, generated the best labeling results.

Successful transplantation of human hepatoblastoma into immunodeficient mice

Six hepatoblastomas (HBs) from pediatric patients were transplanted into immunodeficient NMRI nu/nu mice. Cells from two fetal HBs did not develop tumors. In contrast, xenografts derived from three nonpretreated HBs and one HB after three courses of chemotherapy, all comprising embryonal cells, showed growth after 8 to 10 weeks. The take rates of HB varied from 60% to 90% (mean, 80%). Histologically, they resembled their originals in the pattern of fetal and embryonal differentiated areas and contained hematopoietic foci. The tumors produced high levels of alpha-feto-protein in the patients and the animals. In contrast to the patients, tumor-bearing mice did not display elevated platelet counts. During serial grafting, growth rates of the tumors gradually increased, and hematopoiesis was no longer detectable; however, histologically, a dedifferentiation could not be clearly identified. The addition of viable human or murine fibroblasts to inoculated cells of three nude mouse HBs resulted in a significant increase in the growth rate of all tumors and reappearance of hematopoiesis in three of the examined 10 xenografts of one HB. The authors conclude that HB xenografts in immunodeficient mice are a feasible in vivo model for studies of the biological behavior of this tumor.

Infrequent mutations of the TP53 gene and no amplification of the MDM2 gene in hepatoblastomas

We have investigated the mutation of the TP53 gene in hepatoblastomas (HBLs) by using polymerase chain reaction-single strand conformation polymorphism and direct sequencing in 38 HBL tumor samples and in two HBL cell lines. We detected the TP53 gene mutation in an anaplastic hepatoblastoma cell line, but no aberration of the TP53 gene (exons 5-9) was found in tumor samples and in the other HBL cell line. The mutation of the cell line was a missense mutation from GAC (asparagine) to CAC (histidine) at codon 281, which was different from the G-to-T transversion of codon 249 that is frequently found in adult hepatocellular carcinomas (HCCs). In addition, we performed Southern blot analysis of the MDM2 gene, but we did not find MDM2 gene amplification in 19 cases tested. Our results suggest that, in contrast to the findings in HCCs in adults, TP53 gene aberrations are not involved in the development or progression of HBLs in children.

Immunoreactivity of sinusoids in hepatoblastoma: an immunohistochemical study using lectin UEA-1 and antibodies against endothelium-associated antigens, including CD34

Sinusoids are found not only in the normal liver but also in certain liver tumours, including hepatoblastoma, the most common malignant liver tumour in childhood. In this study, sinusoids in 12 hepatoblastomas, of various subtypes, and in normal liver were investigated with UEA-1 and antibodies against von Willebrand's factor, CD31 and CD34 to detect differences of possible diagnostic significance. In the normal liver, staining of sinusoids was seen with all these markers, but it was focal and confined to a few sinusoids near the portal tracts. In hepatoblastoma, the endothelial markers reacted with the sinusoids to varying extents. UEA-1 and anti-CD34 usually stained the majority of these vessels, anti-CD34 staining greater numbers of sinusoids and with greater intensity. Immunostaining revealed that both number and spatial organization of sinusoids in hepatoblastoma are dependent on the subtype. In addition to staining of endothelium, one of the two small cell hepatoblastomas exhibited strong immunoreactivity of the tumour cells for CD34. These findings show that the marked difference in sinusoidal immunoreactivity for CD34 between normal liver and hepatoblastoma could be useful for discriminating between non-neoplastic liver tissue and highly differentiated fetal hepatoblastoma. Our findings also show that small cell hepatoblastoma, in addition to acute leukaemia, should be considered when immunoreactivity for CD34 is found in small round and blue cell tumours in childhood.

Dissimilar frequency of hepatoblastomas and hepatic cystadenomas and adenocarcinomas arising in hepatocellular neoplasms of D2B6F1 mice initiated with N-nitrosodiethylamine and subsequently given Aroclor-1254, dichlorodiphenyltrichloroethane, or phenobarbital

Aroclor-1254 (Ar-1254) and dichlorodiphenyltrichloroethane (DDT) were compared to phenobarbital (PB) for their ability to promote hepatocellular proliferative lesions to hepatocellular adenomas and carcinomas and to hepatoblastomas in D2B6F1 male mice initiated with N-nitrosodiethylamine (NDEA). Hepatocellular neoplasms developed in all mice given NDEA and were more numerous in mice fed promoters. Multiplicities decreased in the order Ar-1254 > PB > DDT, indicating that Ar-1254 was more potent than either PB or DDT at the dosage levels used. PB was the most effective of the 3 agents in stimulating the evolution of hepatocellular neoplasms to hepatoblastoma. The incidence of hepatoblastomas in the NDEA.PB group was 72% but was only 27% in NDEA-initiated, DDT-promoted mice and 33% in low-dose and only 9% in high-dose Ar-1254-promoted mice. In contrast, lesions resembling benign and malignant cholangiocellular neoplasms were frequently found within hepatocellular tumors in Ar-1254-promoted mice but not in mice fed PB or DDT, either alone or after NDEA. Some cystic glandular structures in Ar-1254-promoted mice contained mucous cells, argentaffin cells, and Paneth cells and thus constituted intestinal metaplasia. Hepatoblastoma and intestinal metaplasia/cholangiocellular tumor morphology appear to constitute different patterns of genetic programming induced by certain promoters in expanding clones of initiated hepatocytes, on favorable genetic backgrounds such as that of D2B6F1 male mice.

Hepatic neoformations

The aim of the paper is an accurate histologic description and illustration of those liver lesions that are usually summarized under the heading of "hepatic tumors and related subjects". For in some cases it may be unclear or at least controversial, whether the individual lesion is indeed an autonomous neoplasia or a malformation, regeneration or hyperplasia, the indifferent master term of neoformation is introduced, based on the fact that all of them are characterized by a cellular multiplication. According to common definitory practice the survey distinguishes between mesenchymal (angiomatous and non angiomatous) and epithelial neoformations. Among the latter hepatocellular and cholangiocellular types are distinguished, the criterium for differentiation being a phenomenological one, which is by no means identical with a histogenetical statement. The definition of subgroups mostly adheres to current nomenclatory usage; only occasionally--in the group of endothelial tumors--a novel term is employed, in view of brevity and coordination with the overall system of neoformations.

P53 protein expression in hepatoblastoma: an immunohistochemical investigation

Mutations of the p53 tumor suppressor gene with immunohistochemically detectable expression of p53 protein have been described in many different malignant tumors. In this study, 12 hepatoblastomas of various subtypes were investigated immunohistochemically with a monoclonal antibody for the expression of p53 protein. Immunoreactivity for p53 protein was found in both small cell tumors investigated and in embryonal areas in two out of eight tumors, but not fetal (eight tumors) or mesenchymal (four tumors) areas. The findings show that immunohistochemically detectable expression of p53 protein, which generally indicates mutation of the gene, may also be present in hepatoblastoma. The finding of p53 protein immunoreactivity in both of the small cell tumors but none of the fetal areas is consistent with a proposal in the literature concerning the histogenesis and differentiation of the various subtypes---that fetal hepatoblastoma is the most well-differentiated and small cell hepatoblastoma the least well-differentiated subtype.

Combined cystic teratoma and hepatoblastoma of the liver. Probable divergent differentiation of an uncommitted hepatic precursor cell

BACKGROUND

Hepatic cystic teratoma is an extremely rare tumor and hepatoblastoma a relatively rare tumor of childhood. Their occurrence as a combined tumor has not been previously reported.

METHODS

The relevant clinical, radiologic, and pathologic findings are presented.

RESULTS

A 17-month-old boy presented with an abdominal mass. Imaging studies suggested an intrahepatic teratoma, but serum alpha-fetoprotein levels were extremely elevated. The resected tumor comprised adjoining benign cystic teratoma and epithelial hepatoblastoma. The child remains alive and well 37 months after complete resection of the tumor.

CONCLUSIONS

The tumor was considered most likely to originate from divergent differentiation of a single uncommitted liver precursor cell.

Production of interleukin-1 beta and interleukin-6 in hepatoblastoma

Thrombocytosis and fever are frequent symptoms in children with hepatoblastoma. Interleukin-6 (IL-6) has been shown to mediate thrombocytosis and an acute-phase reaction including fever. We therefore investigated samples from 14 untreated patients with hepatoblastoma for this cytokine and in addition for interleukin-1 alpha (IL-1 alpha), interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha), all of which are known to induce IL-6 production. High serum levels of IL-6 were only found in 3/14 patients; the other cytokines were not detectable. In contrast, 12/14 tumors produced substantial amounts of IL-6 in primary cell culture, while IL-1 beta was found in 3/14 supernatants; IL-1 alpha and TNF-alpha were always negative. Immunoenzymatic staining of fresh tumors revealed that IL-6 is not produced by the tumor cells, but rather by surrounding fibroblasts and endothelial cells. In tumor cells only IL-1 beta, but neither IL-1 alpha, TNF-alpha nor IL-6, could be detected. In co-culture experiments with fibroblasts and endothelial cells, addition of hepatoblastoma cells enhanced IL-6 production. Including an IL-1 receptor antagonist abolished this effect incompletely. Our results suggest that tumor cells in hepatoblastoma induce IL-6 production in surrounding fibroblasts and endothelial cells by virtue of their endogenous secretion of IL-1 beta and supposedly some other, as yet unidentified, mediator.