Growth patterns and interstitial invasion of small hepatocellular carcinoma

Advanced Imaging of Hepatocellular Carcinoma: A Review of Current and Novel Techniques

Hepatocellular carcinoma (HCC) is the most common primary carcinoma arising from the liver. Although HCC can arise de novo, the vast majority of cases develop in the setting of chronic liver disease. Hepatocarcinogenesis follows a well-studied process during which chronic inflammation and cellular damage precipitate cellular and genetic aberrations, with subsequent propagation of precancerous and cancerous lesions. Surveillance of individuals at high risk of HCC, early diagnosis, and individualized treatment are keys to reducing the mortality associated with this disease. Radiological imaging plays a critical role in the diagnosis and management of these patients. HCC is a unique cancer in that it can be diagnosed with confidence by imaging that meets all radiologic criteria, obviating the risks associated with tissue sampling. This article discusses conventional and emerging imaging techniques for the evaluation of HCC.

Oct3/4 is potentially useful for the suppression of the proliferation and motility of hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) cells are immature compared with healthy mature hepatocytes. Transcription factors serve a role in hepatocyte differentiation. The expression levels of transcription factors in HCC cell lines have been investigated to determine potential therapeutic targets. In the present study, the HLE, HLF, PLC/PRF/5, Huh-7, Hep3B, Huh-6 and HepG2 HCC cell lines were subjected to reverse-transcription polymerase chain reaction (RT-PCR) of transcription factors, including NANOG, Oct3/4, GATA binding protein 4 (GATA4), GATA6 and hematopoietically expressed homeobox (HHEX). In addition, these cell lines were analyzed using RT-quantitative PCR (RT-qPCR) of NANOG and Oct3/4. The 201B7 human induced pluripotent stem cells were evaluated as a model of pluripotent cells. The HLF cells were transfected with Oct3/4 small interfering RNA (siRNA) and used in an MTS colorimetric assay and a scratch assay. NANOG was not expressed in any of the cell lines. However, GATA4, GATA6 and HHEX were expressed in the majority of the HCC cell lines. In addition, NANOG and Oct3/4 were expressed in 201B7 cells. Oct3/4 was expressed in HLE, HLF and Hep3B cells; however, its expression levels were significantly reduced compared with those in 201B7 cells. RT-qPCR demonstrated that the expression of Oct3/4 siRNA suppressed the proliferation and motility of HLF cells. Oct3/4 siRNA may be a potentially effective therapy for the suppression of the proliferation and motility of HCC cells.

Diagnostic accuracy of contrast-enhanced dynamic CT for small hypervascular hepatocellular carcinoma and assessment of dynamic enhancement patterns: Results of two-year follow-up using cone-beam CT hepatic arteriography

Objective

To evaluate the accuracy of CT for small, hypervascular hepatocellular carcinomas (HCCs) and assess the enhancement patterns on CT.

Materials and methods

Ninety-nine patients who underwent cone-beam CT hepatic arteriography (CBCT-HA) during initial chemoembolization for HCC suspected on CT were enrolled in this study. A total of 297 hypervascular HCCs (142 ≥ 1 cm, 155 < 1 cm) were confirmed as HCCs based on two-year follow-up CT and CBCT-HA images. During the two-year follow-up, pre-existing hypervascular foci on CBCT-HA were regarded as HCCs at the initial presentation. Two radiologists categorized HCCs according to the following enhancement patterns on CT: type I, arterial enhancement and washout; type II, arterial enhancement without washout; and type III, no arterial enhancement. Two blinded reviewers rated the possibility of HCC.

Results

For the 297 HCCs, the enhancement patterns according to size were as follows: type I ≥1 cm in 114 HCCs; type I <1 cm in 40 HCCs; type II ≥1 cm in 16 HCCs; type II <1 cm in 37 HCCs; type III ≥1 cm in 12 HCCs; and type III <1 cm in 10 HCCs. The remaining 68 HCCs (22.9%) were not detected on CT. The detection rates of HCCs ≥ 1 cm were 83.1%, 76.8%, and 83.1% in the formal report for reviewer 1 and reviewer 2. In comparison, the detection rates of HCCs < 1 cm were 20.6%, 17.4%, and 17.4% in the formal report for reviewer 1 and reviewer 2.

Conclusion

Many subcentimeter sized hypervascular HCCs were frequently missed or not evident on CT at the initial diagnostic workup. CT has limitations for diagnosing HCCs that are <1 cm in size or have atypical enhancement patterns.

Hepatocyte selection medium-enriched hepatocellular carcinoma cells are positive for α-fetoprotein and CD44

Tissues surrounding hepatocellular carcinomas (HCCs) lack glucose. Hepatocyte selection medium (HSM) is deficient in glucose and is supplemented with galactose. HCC cells were cultured in HSM to investigate the stem cell markers α-fetoprotein (AFP) and cluster of differentiation 44 (CD44). HCC cells (HLF and PLC/PRF/5 cells) were cultured in HSM. Viable cell numbers were determined on days 0 and 7 following culture in HSM. RNA was isolated and subjected to reverse transcription-quantitative PCR (RT-qPCR) to analyze the mRNA expression levels of AFP and CD44. Immunostaining was performed to analyze the protein levels of AFP and CD44. The number of viable cells was significantly decreased on day 7 following culture in HSM. The expression levels of AFP and CD44 increased on day 7 as assessed using RT-qPCR. Immunostaining confirmed the results of RT-qPCR analysis. The number of viable HCC cells was decreased in HSM, whereas the expression levels of AFP and CD44 increased. Therefore, HSM is potentially useful for the enrichment of HCC cells with cancer stem cell characteristics.

2-Deoxyglucose and sorafenib synergistically suppress the proliferation and motility of hepatocellular carcinoma cells

Cancer cells consume more glucose than normal cells, mainly due to their increased rate of glycolysis. 2-Deoxy-d-glucose (2DG) is an analogue of glucose, and sorafenib is a kinase inhibitor and molecular agent used to treat hepatocellular carcinoma (HCC). The present study aimed to demonstrate whether combining 2DG and sorafenib suppresses tumor cell proliferation and motility more effectively than either drug alone. HLF and PLC/PRF/5 HCC cells were incubated with sorafenib with or without 1 µM 2DG, and subjected to a proliferation assay. A scratch assay was then performed to analyze cell motility following the addition of 2DG and sorafenib in combination, and each agent alone. RNA was isolated and subjected to reverse transcription-quantitative polymerase chain reaction to analyze the expression of cyclin D1 and matrix metalloproteinase-9 (MMP9) following the addition of 2DG and sorafenib in combination and each agent alone. Proliferation was markedly suppressed in cells cultured with 1 µM 2DG and 30 µM sorafenib compared with cells cultured with either agent alone (P<0.05). In addition, levels of Cyclin D1 expression decreased in cells exposed to 3 µM sorafenib and 1 µM 2DG compared with cells exposed to 2DG or sorafenib alone (P<0.05). Scratch assay demonstrated that the distance between the growing edge of the cell sheet and the scratched line was shorter in cells cultured with sorafenib and 2DG than in cells cultured with 2DG or sorafenib alone (P<0.05). Levels of MMP9 expression decreased more in cells treated with both sorafenib and 2DG than in cells treated with 2DG or sorafenib alone (P<0.05). Therefore, 2DG and sorafenib in combination suppressed the proliferation and motility of HCC cells more effectively than 2DG or sorafenib alone, and a cancer treatment combining both drugs may be more effective than sorafenib alone.

Cell death in a co-culture of hepatocellular carcinoma cells and human umbilical vascular endothelial cells in a medium lacking glucose and arginine

Human primary hepatocytes are able to survive in a medium without glucose and arginine that is instead supplemented with galactose and ornithine (hepatocyte selection medium; HSM). This is because the cells produce glucose and arginine by the action of galactokinase (GALK) and ornithine carbamoyltransferase (OTC), respectively. It was expected that hepatocellular carcinoma (HCC) cells do not survive in HSM. In the current study, HCC cell lines (namely HLE, HLF, PLC/PRL/5, Hep3B and HepG2) and human umbilical vascular endothelial cells (HUVECs) were cultured in HSM, and the expression levels of GALK1, GALK2 and OTC were analyzed by reverse transcription-quantitative polymerase chain reaction. HLE, HLF and PLC/PRL/5 cells died on day 11, while Hep3B, HepG2 and HUVECs died on day 7. HLF cells were further analyzed as these cells had lower expression levels of GALK1, GALK2 and OTC compared with adult liver cells, and survived until day 11. In these cells, the expression levels of GALK1, GALK2 and OTC did not change on days 3 and 7 as compared to day 0. In addition, a co-culture of HLF cells with HUVECs was established and the medium was changed to HSM. It was observed that HLF cells and HUVECs in co-culture were damaged in HSM. In summary, HCC cells and HUVECs died in a medium without glucose and arginine that was supplemented with galactose and ornithine. HCC cells and HUVECs were damaged in HSM, suggesting a potential application for treatment with the medium.

Suppression of hepatocellular carcinoma cell proliferation by short hairpin RNA of frizzled 2 with Sonazoid-enhanced irradiation

Short-hairpin RNA of frizzled-2 (shRNA-Fz2) is known to suppress the proliferation of hepatocellular carcinoma (HCC) cells; however, its effect on HCC cell motility is unknown. In this study, suppression of HCC cell motility by shRNA-Fz2 was analyzed, and introduction of shRNA-Fz2 into HCC cells was facilitated with ultrasound (US) irradiation generated from a diagnostic US device, which was enhanced by the contrast-enhanced US reagent Sonazoid. The HCC cell lines HLF and PLC/PRF/5 that were transfected with shRNA-Fz2 were plated to form monolayers, following which the cell monolayers were scratched with a sterile razor. After 48 h, the cells were stained with hematoxylin and eosin, and the distance between the growing edge of the cell layer and the scratch lines was measured. Total RNA from the cells was isolated and subjected to real-time quantitative PCR to quantify matrix metalloproteinase 9 expression at 48 h after transfection of shRNA-Fz2. Starch-iodide method was applied to analyze the generation of H2O2 following US irradiation with the addition of Sonazoid in the liquid, and cell proliferation was analyzed 72 h later. The distances between the growing edge of the cell layer and the scratch lines and MMP9 expression levels were significantly decreased with transfection of shRNA-Fz2 (P<0.05). In the starch-iodide method, absorbance significantly decreased with the addition of Sonazoid (P<0.05), which suggested that US irradiation with Sonazoid generated H2O2 and enhanced sonoporation. ShRNA-Fz2 suppressed cell proliferation of both cell lines at a mechanical index of 0.4. Motility of HLF cells and PLC/PRF/5 cells was suppressed by shRNA-FZ2. Sonazoid enhanced sonoporation of the cells with the diagnostic US device and the suppression of proliferation of both HCC cell lines by shRNA-Fz2.

Niclosamide suppresses migration of hepatocellular carcinoma cells and downregulates matrix metalloproteinase-9 expression

Metastasis negatively affects the prognosis of hepatocellular carcinoma (HCC). In the present study, niclosamide, which is known to suppress the proliferation of HCC cells, was investigated for possible suppressant effects on the migration of HCC cells. HLF and PLC/PRF/5 HCC cells were cultured in the presence of niclosamide. Cell proliferation was analyzed using the MTS assay. Cell migration was measured by performing a scratch assay. Expression levels of cyclin D1 and matrix metalloproteinase 9 (MMP9) were analyzed by performing revers transcription-quantitative polymerase chain reaction. Compared with the control treatment, treatment with 10 µm niclosamide suppressed the proliferation of the HLF and PRL/PRF/5 cells to 49.9±3.7 and 17.9±11.5% (P<0.05), respectively. Furthermore, compared with the control treatment, treatment with 1.0 µM niclosamide downregulated the expression of cyclin D1 to 52.4±4.4 and 23.9±5.4% (P<0.05) in the HLF and PRL/PRF/5 cells, respectively. In the scratch assay, treatment of the HLF cells with niclosamide (1.0 µm) decreased the distance of the scratched line from the growing edge to 4.6±1.0 mm compared with the 9.2±1.4 mm observed with the control treatment (P<0.05). Similarly, treatment of the PRL/PRF/5 cells with niclosamide (1.0 µm) also decreased the distance of the scratched line from the growing edge to 3.0±0.8 mm compared with the 5.5±0.9 mm observed with the control treatment (P<0.05). Further, MMP9 expression levels in the HLF cells treated with 1.0 µm niclosamide decreased to 22.4±1.76% (P<0.05) compared with those in the untreated control HLF cells. Similarly, expression level of MMP9 in the PRL/PRF/5 cells treated with 1.0 µm niclosamide deceased to 18.7±10.7% (P<0.05) compared with those in the untreated control PRL/PRF/5 cells. Overall, niclosamide downregulated the expression of MMP9 in and suppressed the migration of HCC cells.

SU11274 suppresses proliferation and motility of pancreatic cancer cells

Mesenchymal-epithelial transition factor (c-Met) is associated with the proliferation and motility of cancer cells. c-Met expression has been detected in surgical pancreatic cancer specimens, and its overexpression is associated with a poor prognosis. SU11274 is a specific inhibitor of c-Met. In the present study, the cell proliferation and motility of pancreatic cancer cells treated with SU11274 was investigated. The PANC-1, MIA-Paca2, NOR-P1, PK-45H, PK-1 and PK-59 pancreatic cancer cell lines were used. The expression of c-Met and cyclin D1 was analyzed by quantitative polymerase chain reaction. In addition, a 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium inner salt assay was performed to assess cell proliferation, and a scratch assay was performed to assess cell motility. c-Met expression was higher in PANC-1, PK-45H, PK-1 and PK-59 cell lines compared with that in normal pancreatic tissue. Following treatment with 30 µM SU11274, the proliferation of MIA-Paca2 and PK-45H cells was suppressed to 19.8±10.7% (P<0.05) and 45.8±14.8% (P<0.05) of the control level, respectively. Furthermore, cyclin D1 expression was downregulated to 43.7±17.9% (P<0.05) and 53.2±18.6% (P<0.05) of the control level in the MIA-Paca2 and PK-45H cell lines, respectively, following treatment with 30 µM SU11274. In addition, cell motility was reduced to 1.0±0.3% in MIA-Paca2 (P<0.05) and 14.7±3.5% in PK-45H (P<0.05) following treatment with 30 µM SU11274, compared with the motility of untreated cells. These results indicated that SU11274 suppresses the proliferation of pancreatic cancer cells via the downregulation of cyclin D1. The present study also demonstrated that cell motility was suppressed by treatment with SU11274.

Co-culture of hepatocellular carcinoma cells and human umbilical endothelial cells damaged by SU11274

Mesenchymal-epithelial transition factor (c-Met) is a receptor that binds to the hepatocyte growth factor and is upregulated in hepatocellular carcinoma (HCC). The anti-tumor effects of (3Z)-N-(3-chlorophenyl)-3-({3,5-dimethyl-4-[(4- methyl-piperazin-1-yl)carbonyl]-1H-pyrrol-2-yl}methylene)-N-me- thyl-2-oxo-2,3-dihydro-1H-indole-5-sulfonamide (SU11274), a c-Met inhibitor, were investigated in the present study. HCC cells (HLE, HLF, PLC/PRL/5, Hep3B, Huh-6 and HepG2) and human umbilical vein endothelial cells (HUVECs) were used. Quantitative polymerase chain reaction was performed to detect the expression level of c-Met in HCC and HUVECs, and cyclin D1 in HCC. The 3-(4,5-dimethylthiazol-2-yl)-5-(3-car-boxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium inner salt assay was performed to assess the proliferation of the HCC cells and HUVECs cultured with SU11274. Co-culture of HLF or PLC/PRL/5 cells and HUVECs was established as an in vitro model of HCC tissues. The expression levels of c-Met in HLE, HLF, PLC/PRL/5, Hep3B, Huh-6 and HepG2, adult healthy liver and HUVECs were 4.43±0.50, 1.61±0.18, 3.70±0.08, 0.81±0.18, 6.60±1.29, 1.06±0.35, 1.00±0.09 and 88.8±17.3 (mean ± standard deviation), respectively. SU11274 (30 μM) suppressed the proliferation of HLF, PLC/PRL/5 and HUVECs to 11.0±9.4, 46.5±30.7 and 29.4±5.0%, respectively. SU11274 (30 μM) decreased the expression levels of cyclin D1 in HLF and PLC/PRL/5 cells to 45.1±11.6 and 30.1±10.3%, respectively. SU11274, at a concentration of 30 μM damaged the morphology of the co-cultures of HLF or PLC/PRL/5 cells with HUVECs and all the cells died. c-Met is highly expressed in HUVECs and HCC cells, but not in Hep3B. At a 30-μM concentration, SU11274 suppresses the proliferation of HLF, PLC/PRL/5 and HUVECs. SU11274 (30 μM) damages the co-cultures of HLF or PLC/PRL/5 cells with HUVECs.

Picropodophyllin and sorafenib synergistically suppress the proliferation and motility of hepatocellular carcinoma cells

Resistance is one limitation of sorafenib in the treatment of hepatocellular carcinoma (HCC). Insulin-like growth factor-1 receptor (IGF-1R) is involved in cancer cell proliferation. To assess the potential synergistic antitumor effects of picropodophyllin (PPP), an IGF-1R inhibitor, HLF and PLC/PRL/5, HCC cells were treated with PPP alone or PPP in combination with sorafenib, a multikinase inhibitor. Normal human umbilical vein endothelial cells (HUVECs) were also used to analyze the antiangiogenic effects of the drugs. HCC cells and HUVECs were cultured on 96-well plates, and then treated with PPP, with and without the addition of sorafenib. A 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium inner salt assay and hematoxylin and eosin staining were then performed 48 h later. The HCC cells were also analyzed using scratch assays and hematoxylin and eosin staining after 48 h. The proliferation of HLF, PLC/PRF/5 and HUVEC cells was suppressed by the combination of 0.2 μM PPP and 3 μM sorafenib more effectively than by 10 μM sorafenib alone. The motility of HLF and PLC/PRF/5 cells was also suppressed to a greater extent with the combination of PPP at 0.2 μM and sorafenib at 3 μM than with sorafenib at 10 μM alone. The cells that had been treated with 0.2 μM PPP and 3 μM sorafenib also exhibited pyknotic nuclei, which is characteristic of apoptosis. In conclusion, PPP enhanced sorafenib-mediated suppression of proliferation and motility in HCC cells. Therefore, the combination of PPP and sorafenib may exert antitumor and antiangiogenic effects.

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

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

Assessment of stromal invasion for correct histological diagnosis of early hepatocellular carcinoma

Stromal invasion (invasive growth of tumor tissue into portal tracts and fibrous septa) is now recognized as the most important finding in the diagnosis of the well-differentiated type of early hepatocellular carcinomas (HCCs). In differentiating stromal invasion from pseudoinvasion (benign hepatic tissue in fibrous stroma), the following 5 items are useful: (1) macroscopic or panoramic views of the histological specimen, (2) the amount of fibrous components of stroma, (3) destruction of the structure of portal tracts, (4) loss of reticulin fibers around cancer cells, and (5) cytokeratin 7 immunostaining for ductular proliferation. Knowledge of stromal invasion is also useful for a better understanding of the vasculature (hypovascular HCCs) and histological features (fatty change) of early HCCs. Invasion of preexisting arteries and portal veins causes hypo-vascularity of HCCs. Further, hypovascularity causes fatty change as a hypoxic change of cancer tissues.

Sorafenib suppresses the cell cycle and induces the apoptosis of hepatocellular carcinoma cell lines in serum-free media

To suppress the invasion of hepatocellular carcinoma (HCC) cells into surrounding connective tissues during metastasis, we investigated the usefulness of sorafenib. In order to search for model cell lines, cell numbers were counted to reveal cell lines with the potential to proliferate in serum-free media. Cell proliferation and cell motility were analyzed with the MTS and wound assay, respectively. 5-Bromo-2'-deoxyuridine (BrdU) labeling and mitotic and apoptotic indices were analyzed to assess the cell cycle and apoptosis. The expression levels of cyclin D1 and the cleavage of caspase-3 were analyzed by Western blotting. HLF cells exhibited growth in the serum-free medium, while the other cell lines examined did not. Sorafenib suppressed the cell proliferation and motility of the HLF cells in the serum-free media. Both indices of BrdU and mitotic potential decreased and the apoptotic index was increased in the serum-free media with sorafenib, suggesting that the cell cycle was suppressed and apoptosis was induced. The expression levels of cyclin D1 decreased and the cleavage of caspase-3 was noted in the serum-free media with sorafenib. Sorafenib may be suitable for molecular therapy to suppress the metastasis of HCC.

Recent advances in the natural history of hepatocellular carcinoma

Ongoing advances in liver disease management and basic research in recent years have changed our knowledge of the natural history of hepatocellular carcinoma (HCC). Indeed, the natural history of this tumor is fairly long and covers a preclinical and a clinical phase. Some of the biological steps involved in cell transformation and different carcinogenic pathways have been identified, disclosing potential novel markers for HCC. Following the progress in surveillance and early diagnosis, much more is now known about precancerous lesions and the process leading to overt HCC, including growth patterns, dedifferentiation and neoangiogenenesis. In particular, research has focused on clinical and biological factors predicting tumor aggressiveness and patients' prognosis. Lastly, clinical studies have described tumor presentation, evolution and causes of patients' death and how the new knowledge has influenced clinical management and patients' survival in recent years. By addressing 10 key questions, this review will summarize well-established and novel features of the natural history of HCC.

Recent advances in the diagnosis of hepatocellular carcinoma

In the last decade, new imaging techniques have become available, offering the possibility of investigating contrast perfusion of liver nodules in cirrhosis. It is now accepted that a non-invasive diagnosis of hepatocellular carcinoma (HCC) can be established based on the vascular pattern, obtained with pure blood pool contrast agents. The diagnostic pattern includes: hypervascularity in the arterial phase (15-35 s after contrast injection), consisting in a contrast signal in the nodule greater than in the surrounding parenchyma, followed by contrast wash out, which leads the nodule to show the same, or, more specifically, a lower contrast signal, than the surrounding parenchyma in the portal and late phases (>40 s after injection). Such a pattern can be obtained not only by computed tomography or magnetic resonance imaging, but also by contrast-enhanced ultrasonography, most simply with real-time low mechanical index harmonic imaging ultrasound equipment with second-generation ultrasound contrast agents. The risk of false-positive diagnosis of malignancy isnearly abolished when the functional vascular pattern is not the only feature, but is superimposed on a nodule visible also without contrast. One single contrast imaging technique may suffice to make a diagnosis of HCC if the nodule is >1 cm in diameter and has developed during a surveillance program. Other types of contrast agents, such as those taken up by the reticular-endothelial system cells, may offer additional diagnostic clues, but definitive evidence of their efficacy is still to be produced. In conclusion, contrast-enhanced imaging techniques now offer the possibility of a non-invasive diagnosis of HCC in a large number of cases, reducing the need of invasive investigations, such as ultrasound-guided biopsy or angiography.

Diagnostic discrepancy of early hepatocellular carcinoma between Japan and West

The diagnoses for a range of hepatocellular neoplastic lesions amongst Japanese and Western pathologists show a striking lack of consistency, especially in distinguishing dysplastic nodules (DN) from very well-differentiated hepatocellular carcinomas (HCC). Namely, very well-differentiated HCC showing a vaguely nodular appearance diagnosed by Japanese pathologists tends to be diagnosed as high-grade DN by Western pathologists. Both Japanese and Western pathologists agreed that "stromal invasion", which is tumor cell invasion into the intra-tumoral portal tracts, is considered the most helpful morphologic clue to distinguish high-grade DN from well-differentiated HCC.

Classification tool for the systematic histological assessment of hepatocellular carcinoma, macroregenerative nodules, and dysplastic nodules in cirrhotic liver

AIM: To design a classification tool for the histological assessment of hepatocellular carcinoma (HCC), dysplastic nodules (DN), and macroregenerative nodules (MRN) in cirrhotic liver.

METHODS: Two hundred and twelve hepatocellular nodules (106 HCC; 74 MRN; 32 DN) were assessed systematically, quantitatively, and semiquantitatively as appropriate for 10 histological features that have been described as helpful in distinguishing small HCC, DN, and MRN in cirrhotic livers. The data were analyzed by multiple correspondence analysis (MCA).

RESULTS: MCA distributed HCC, DN, and MRN as defined by traditional histological evaluation as well as the individual histological variables, in a “malignancy scale”. Based on the MCA data representation, we created a classification tool, which categorizes an individual nodular lesion as MRN, DN, or HCC based on the balance of all histological features (i.e., vascular invasion, capsular invasion, tumor necrosis, tumor heterogeneity, reticulin loss, capillarization of sinusoids, trabecular thickness, nuclear atypia, and mitotic activity). The classification tool classified most (83%) of a validation set of 47 nodules in the same way as the routine histological assessment. No discrepancies were present for DN and MRN between the routine histological assignment and the classification tool. Of 25 HCC assigned by routine assessment in the validation set, 8 were assigned to the DN category by the classification tool.

CONCLUSION: We have designed a classification tool for the histological assessment of HCC and its putative precursors in cirrhotic liver. Application of this tool systematically records histological features of diagnostic importance in the evaluation of small HCC.

Histopathology of liver cancers

Recently, new pathomorphologic information about early-stage small hepatocellular carcinoma (HCC) and the multi-step process of human hepatocarcinogenesis has been obtained, along with advances in the development of diagnostic modalities. The most valuable information is that in the majority of cases HCC arises as a very well differentiated cancer and proliferates with a stepwise process of dedifferentiation. In addition, it has been suggested that many HCCs seem to arise from dysplastic nodules (DNs) on the basis of the following evidence: the presence of DNs containing HCC foci, frequent association of DNs in the vicinity of HCC, and clinical progression from DN to HCC. However, as many HCCs are still detected at an advanced stage, it is also important to understand not only the classical pathologic features of HCC but also unusual features such as scirrhous change, sarcomatous change, fibrolamellar variant, and intra-bile duct or intra-atrial tumor growth.

Focus on dysplastic nodules and early hepatocellular carcinoma: an Eastern point of view

Although increasing numbers of equivocal nodular lesions have been detected in patients with liver cirrhosis with the development of various diagnostic imaging modalities, the pathological diagnosis of small, well-differentiated hepatocellular carcinoma (HCC) in the early stage and of high-grade dysplastic nodules (DNs) is a controversial issue among both Japanese and Western pathologists. In particular, many of the vaguely nodular HCCs of well-differentiated HCC diagnosed by Japanese pathologists tend to be interpreted as high-grade DNs rather than HCC by Western pathologists. In contrast, many of the high-grade DNs diagnosed by Western pathologists are interpreted as well-differentiated HCC by Japanese pathologists. The reasons for the discrepancy between Japanese and Western pathologists can be explained by the following: for Western pathologists, most information comes from the study of HCC and advanced cirrhosis explanted at liver transplantation without detailed clinical information about the nodules; for Japanese pathologists, most information comes from the examination of surgical and biopsy materials together with detailed clinical information that includes meticulous follow-up data on the clinical course of the nodular lesions. To resolve the diagnostic confusion concerning equivocal nodular lesions in the cirrhotic liver, it is necessary to promote the active exchange of clinicopathologic information between Japan and Western countries.

Natural history of inoperable hepatocellular carcinoma: estrogen receptors' status in the tumor is the strongest prognostic factor for survival

Clinical course in hepatocellular carcinoma may be very different. We prospectively evaluated 96 patients with hepatocellular carcinoma unsuitable for radical therapy to investigate factors that could influence survival. Clinical, pathologic, and molecular data of patients were analyzed by univariate and multivariate analysis. The overall actuarial probability of survival at year 1, 2, 3, 4, 5, and 6 was 72%, 41%, 38%, 24%, 20%, and 9%. At univariate analysis, alpha-fetoprotein (AFP) (P =.0082); alkaline phosphatase (P =.0281); bilirubin (P =.0076); etiology (P =.0001); increment of tumor mass at month 3 (P =.0051); type of estrogen receptor (ER) in the tumor (P =.0000); prothrombin time (P =.0003); and portal vein thrombosis (P =.0000) had prognostic significance. At multivariate analysis, only type of ER (P =.0000) and bilirubin (P =.0030) showed independent predictive value for mortality. Survival was significantly longer in patients with wild-type estrogen receptors (P =.0000). Cumulative probability of survival at year 1, 2, 3, 4, 5, and 6 was 94%, 66%, 52%, 43%, 35%, and 18% for wild-type and 51%, 21%, 16%, and 9% for variant estrogen receptors (no patients alive after 4 years). Hepatitis B surface antigen (HBsAg)-positive patients with variant ERs had a median survival of 8 months versus 45 months in anti-hepatitis C virus-positive patients with wild-type ERs (P =.0001). In conclusion, (1) the presence of variant liver ER transcripts in the tumor was the strongest negative predictor of survival in inoperable hepatocellular carcinoma; (2) their presence was associated with spontaneous survival significantly worse than in patients with wild-type estrogen receptors; and (3) HBsAg-positive patients with variant receptors were characterized by the worst survival.

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.

Interstitial invasion of well-differentiated hepatocellular carcinoma and subsequent tumor growth

Pathological processes of interstitial invasion of hepatocellular carcinoma (HCC) were investigated in 125 autopsy and seven surgical cases, where selection focused on those occurring in well-differentiated HCC. The invasive pattern of well-differentiated HCC was characterized by the formation of streaks of tumor cell cords running along connective tissue fibers, referred to as a streak pattern. These cell cords were unaccompanied by reticulin frameworks and type IV collagen, which are consistent components of HCC parenchyma. The typical streak pattern was observed only in HCC cases and could be useful in differential diagnosis. Following progressive accumulation or proliferation of the tumor cells within the interstitium, many capillaries appeared between the cell cords while collagen fibers tended to disappear. The tumor cell cords then showed branching and were accompanied by reticulin frameworks, type IV collagen and sinusoidal blood spaces. In the setting of interstitial invasion of well-differentiated HCC, it is suggested that interstitial tissue is converted into HCC parenchyma via the aforementioned steps.

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.