Genes and viruses in hepatobiliary neoplasia

Cholangiocarcinoma: a site-specific update on the current state of surgical management and multi-modality therapy

Biliary tract cancers (BTC) are rare, heterogeneous malignancies that include cholangiocarcinoma and gallbladder cancer (GBC). Cholangiocarcinoma subtypes differ by anatomic location and molecular profile. Currently, resection with lymphadenectomy is the only curative treatment of locally advanced cholangiocarcinoma. Given the high risk of recurrence, multi-modality therapy spanning surgery, chemotherapy, and radiation therapy should be considered. Current data is discordant and there is limited prospective data to support an optimal treatment regimen, though recent studies have demonstrated the utility of adjuvant chemotherapy and chemoradiation in specific settings and patient populations. There is a potential role for neoadjuvant chemotherapy in patients with resectable disease or chemoradiation in select patients with unresectable, locally advanced disease. Randomized clinical trials are necessary to establish the effectiveness of therapies specific to disease sites, especially with the emerging role of immunotherapy and targeted therapy to actionable mutations.

Molecular Pathogenesis of Cholangiocarcinoma

BACKGROUND

Cholangiocarcinomas are a heterogeneous group of malignancies arising from a number of cells of origin along the biliary tree. Although most cases in Western countries are sporadic, large population-based studies have identified a number of risk factors. This review summarises the evidence behind reported risk factors and current understanding of the molecular pathogenesis of cholangiocarcinoma, with a focus on inflammation and cholestasis as the driving forces in cholangiocarcinoma development.

RISK FACTORS FOR CHOLANGIOCARCINOGENESIS

Cholestatic liver diseases (e.g. primary sclerosing cholangitis and fibropolycystic liver diseases), liver cirrhosis, and biliary stone disease all increase the risk of cholangiocarcinoma. Certain bacterial, viral or parasitic infections such as hepatitis B and C and liver flukes also increase cholangiocarcinoma risk. Other risk factors include inflammatory disorders (such as inflammatory bowel disease and chronic pancreatitis), toxins (e.g. alcohol and tobacco), metabolic conditions (diabetes, obesity and non-alcoholic fatty liver disease) and a number of genetic disorders.

MOLECULAR PATHOGENESIS OF CHOLANGIOCARCINOMA

Regardless of aetiology, most risk factors cause chronic inflammation or cholestasis. Chronic inflammation leads to increased exposure of cholangiocytes to the inflammatory mediators interleukin-6, Tumour Necrosis Factor-ɑ, Cyclo-oxygenase-2 and Wnt, resulting in progressive mutations in tumour suppressor genes, proto-oncogenes and DNA mismatch-repair genes. Accumulating bile acids from cholestasis lead to reduced pH, increased apoptosis and activation of ERK1/2, Akt and NF-κB pathways that encourage cell proliferation, migration and survival. Other mediators upregulated in cholangiocarcinoma include Transforming Growth Factor-β, Vascular Endothelial Growth Factor, Hepatocyte Growth Factor and several microRNAs. Increased expression of the cell surface receptor c-Met, the glucose transporter GLUT-1 and the sodium iodide symporter lead to tumour growth, angiogenesis and cell migration. Stromal changes are also observed, resulting in alterations to the extracellular matrix composition and recruitment of fibroblasts and macrophages that create a microenvironment promoting cell survival, invasion and metastasis.

CONCLUSION

Regardless of aetiology, most risk factors for cholangiocarcinoma cause chronic inflammation and/or cholestasis, leading to the activation of common intracellular pathways that result in reactive cell proliferation, genetic/epigenetic mutations and cholangiocarcinogenesis. An understanding of the molecular pathogenesis of cholangiocarcinoma is vital when developing new diagnostic biomarkers and targeted therapies for this disease.

Efficacy and safety of trametinib in Japanese patients with advanced biliary tract cancers refractory to gemcitabine

Gemcitabine‐based therapy remains the mainstay of treatment for patients with biliary tract cancers (BTCs) with no second‐line treatment(s) established yet. Aberrant activation of the MAPK pathway in patients with BTC indicates its importance in BTC. Trametinib is a potent, highly selective, allosteric non‐competitive inhibitor of MEK1/MEK2. In this phase IIa open‐label, single‐arm study, we investigated the efficacy and safety of trametinib in Japanese patients with advanced BTC refractory to gemcitabine‐based therapy. All patients received oral trametinib 2 mg once daily until progressive disease (PD), death, or unacceptable toxicity. The primary objective was to determine the 12‐week non‐PD rate. Secondary assessments included safety, progression‐free survival (PFS), overall survival, and overall response rate. Targeted exome sequencing was used to identify biomarkers for sensitivity or resistance to trametinib monotherapy. Twenty patients (median age, 61.5 years) with carcinoma of gall bladder (40%), intrahepatic (25%) or extrahepatic (30%) bile duct, and ampulla of Vater (5%) were enrolled. The non‐PD rate at week 12 was 10% (95% confidence interval, 1.2‐31.7); it did not reach the threshold rate of 25%. Median PFS was 10.6 weeks (95% confidence interval, 4.6‐12.1) and 1‐year overall survival was 20.0%. Stable disease and PD were observed in 13 (65%) and seven (35%) patients, respectively. No new safety signals were reported. Although the primary end‐point was not met, prolonged PFS was observed in one patient having six somatic variants including synonymous NF1 exon 12 splice variant and a loss‐of‐function variant in ARID1A. Efforts to understand responsive mutations and sensitivity to targeted therapies are warranted. This trial was registered with ClinicalTrials.gov: NCT01943864.

Selumetinib for the treatment of cancer

Introduction: The MAPK pathway is essential for regulation of cellular proliferation, differentiation and survival. Multiple human cancers have demonstrated activation of Raf-mitogen-activated kinase kinase (MEK)-extracellular signal-related kinase signaling, a hallmark of these tumors. Efforts to inhibit various protein kinases in this pathway have led to the development of MEK inhibitors. Selumetinib is one such drug, functioning as an oral, selective non-ATP-competitive MEK1/2 inhibitor. Areas covered: In this article, the authors discuss the underlying biology of MEK inhibition and its rationale in cancer treatment. Furthermore, the authors summarize the clinical development of selumetinib in various tumor types, from initial Phase I studies to randomized Phase II studies, both as monotherapy or in combination with other chemotherapeutics. Expert opinion: Given the frequency of activated MAPK signaling in multiple tumor types, the potent MEK inhibitor selumetinib had strong preclinical and early clinical rationale, particularly in those tumors harboring KRAS or BRAF mutations. While efficacy signals have been seen in various tumor types treated with selumetinib, better biomarkers are needed to select patients most likely to respond favorably to this agent. Furthermore, combinatorial therapy with selumetinib and other targeted agents can likely be optimized to maximize the antitumor effect of inhibiting RAS/MAPK signaling.

The metabolic syndrome and risk factors for biliary tract cancer: a case-control study in China

OBJECTIVES

Recent data show that the metabolic syndrome may play a role in several cancers, but the etiology for biliary tract cancer is incompletely defined. The present aim was to evaluate risk factors for biliary tract cancer in China.

METHODS

A case-control study in which cases were biliary tract cancer patients referred to Peking Union Medical College Hospital (PUMCH). Controls were randomly selected from an existing database of healthy individuals at the Health Screening Center of PUMCH. Data on the metabolic syndrome, liver diseases, family history, and history of diabetes and hypertension were collected by retrospective review of the patients' records and health examination reports or by interview.

RESULTS

A total of 281 patients (102 intrahepatic cholangiocarcinoma (ICC), 86 extrahepatic cholangiocarcinoma (ECC) and 93 gallbladder carcinoma (GC)) and 835 age- and sex-matched controls were enrolled. HBsAg+/anti-HBc+ (P=0.002), history of diabetes (P=0.000), cholelithiasis (P=0.000), TC (P=0.003), and HDL (P=0.000) were significantly related to ICC. Cholelithiasis (P=0.000), Tri (P=0.001), LDL (P=0.000), diabetes (P=0.000), Apo A (P=0.000) and Apo B (P=0.012) were significantly associated with ECC. Diabetes (P=0.017), cholelithiasis (P=0.000) and Apo A (P=0.000) were strongly inversely correlated with GC.

CONCLUSION

Cholelithiasis, HBV infection and metabolic symptoms may be potential risk factors for the development of biliary tract cancer.

Comparison of hepatocellular carcinoma in American and Asian patients by tissue array analysis

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. Although some epidemiologic and etiologic differences between Asian and Western HCC are known, detailed comparative studies with pathologic correlations have not been performed.

METHODS

Paraffin sections of resected HCC specimens from Memorial Sloan-Kettering Cancer Center and Korea University Medical Center were used to construct tissue microarrays. Immunohistochemical staining of microarray sections was performed using antibodies against markers of proliferation and regulators of cell cycle. Patient data were correlated with staining results.

RESULTS

When comparing both cohorts, significant differences were found in expression of p53 and MDM2. In the Asian group, more frequent positive staining for p53 (24%) was observed compared with the American group (9%; P = 0.037). For MDM2, 26% of American cases stained positive compared with 2% of Asian cases (P = 0.0003). No significant differences were found in expression of Ki67, p21, p27, cyclin D1, or bcl2. Female gender, vascular invasion, and lack of viral hepatitis infection correlated with positive MDM2 staining.

CONCLUSION

These data likely correlate with differences in molecular pathogenesis of HCC based on racial and regional differences. These findings may have implications in choice of molecular targeted therapies based on patient ethnicity.

Multi-institutional phase II study of selumetinib in patients with metastatic biliary cancers

PURPOSE

Biliary cancers (BCs) carry a poor prognosis, but targeting the RAS/RAF/mitogen-activated protein kinase kinase (MEK)/extracellular signal-related kinase (ERK) pathway is of significance. Selumetinib is an inhibitor of MEK1/2, so this trial was designed to determine the safety and efficacy of selumetinib in BC.

PATIENTS AND METHODS

This was a multi-institutional phase II study of selumetinib at 100 mg given orally twice per day to patients with advanced BC. The primary end point was response rate. All patients were required to provide tissue before enrolling. The levels of phosphorylated ERK (pERK) and AKT (pAKT) were assessed by immunohistochemistry. Tumors were genotyped for the presence of BRAF- and/or RAS-activating mutations.

RESULTS

Twenty-eight eligible patients with a median age of 55.6 years were enrolled. Thirty-nine percent of patients had received one prior systemic therapy. Three patients (12%) had a confirmed objective response. Another 17 patients (68%) experienced stable disease (SD), 14 of whom (56%) experienced prolonged SD (> 16 weeks). Patients gained an average nonfluid weight of 8.6 pounds. Median progression-free survival was 3.7 months (95% CI, 3.5 to 4.9) and median overall survival was 9.8 months (95% CI, 5.97 to not available). Toxicities were mild, with rash (90%) and xerostomia (54%) being most frequent. Only one patient experienced grade 4 toxicity (fatigue). All patients had tissue available for analysis. No BRAF V600E mutations were found. Two patients with short-lived SD had KRAS mutations. Absence of pERK staining was associated with lack of response.

CONCLUSION

Selumetinib displays interesting activity and acceptable tolerability in patients with metastatic BC. Our results warrant further evaluation of selumetinib in patients with metastatic BC.

Multi-institutional phase II study of selumetinib in patients with metastatic biliary cancers

PURPOSE

Biliary cancers (BCs) carry a poor prognosis, but targeting the RAS/RAF/mitogen-activated protein kinase kinase (MEK)/extracellular signal-related kinase (ERK) pathway is of significance. Selumetinib is an inhibitor of MEK1/2, so this trial was designed to determine the safety and efficacy of selumetinib in BC.

PATIENTS AND METHODS

This was a multi-institutional phase II study of selumetinib at 100 mg given orally twice per day to patients with advanced BC. The primary end point was response rate. All patients were required to provide tissue before enrolling. The levels of phosphorylated ERK (pERK) and AKT (pAKT) were assessed by immunohistochemistry. Tumors were genotyped for the presence of BRAF- and/or RAS-activating mutations.

RESULTS

Twenty-eight eligible patients with a median age of 55.6 years were enrolled. Thirty-nine percent of patients had received one prior systemic therapy. Three patients (12%) had a confirmed objective response. Another 17 patients (68%) experienced stable disease (SD), 14 of whom (56%) experienced prolonged SD (> 16 weeks). Patients gained an average nonfluid weight of 8.6 pounds. Median progression-free survival was 3.7 months (95% CI, 3.5 to 4.9) and median overall survival was 9.8 months (95% CI, 5.97 to not available). Toxicities were mild, with rash (90%) and xerostomia (54%) being most frequent. Only one patient experienced grade 4 toxicity (fatigue). All patients had tissue available for analysis. No BRAF V600E mutations were found. Two patients with short-lived SD had KRAS mutations. Absence of pERK staining was associated with lack of response.

CONCLUSION

Selumetinib displays interesting activity and acceptable tolerability in patients with metastatic BC. Our results warrant further evaluation of selumetinib in patients with metastatic BC.

Beta2-GPI: a novel factor in the development of hepatocellular carcinoma

PURPOSE

This study investigated the effect and clinical significance of beta2-GPI in hepatocellular carcinoma (HCC).

METHODS

Double fluorescent immunostaining analysis was performed in paraffin wax-embedded histological sections of nine HCC parenchyma, seven adjacent non-cancerous tissues and seven control liver tissues from hepatitis B virus (HBV) infected patients using a beta2-GPI polyclonal antibody and a HBV surface antibody. NF-κB activation was assessed by a non-radioactive electrophoretic mobility shift assay (EMSA) and immunofluorescence assay in SMMC-7721 HCC cells exposed to various treatments. The cells were transiently transfected with vectors expressing beta2-GPI (group one), HBsAg (group two), both beta2-GPI and HBsAg (group three), or with a control vector (group four). Untransfected cells (group five) were also used as a control. Alpha fetoprotein (AFP) expressions were also detected by ELISA in all groups.

RESULTS

The highest degree of co-localization of beta2-GPI and HBsAg proteins was seen in the endochylema and occurred at the nuclear border in the cancer tissues. Weak beta2-GPI protein staining was present in the endochylema, with a strong signal for HBsAg protein in HBV control samples. Adjacent non-tumorous liver tissue samples also showed HBsAg staining but stronger beta2-GPI signals in the endochylema. In experiments with SMMC-7721 HCC cells, groups one and two had induced activation of NF-κB with the relative NF-κB DNA-binding activities of 55.84 and 51.12, respectively. However, the highest relative NF-κB DNA-binding activity was observed in group three (80.5). The percentages of cells with NF-κB translocated from the cytoplasm to nucleus in groups one, two, three, four and five compared with total cells were 13.5, 8.7, 24.9, 5.7 and 0.95%, respectively. The mean AFP levels were significantly higher in group three (0.0640 ± 0.0059) than in group five (P < 0.001). It appeared higher in group three than in group one (0.0562 ± 0.0060, P < 0.05) and group four (0.0585 ± 0.0040, P < 0.05), while no significant differences were seen between groups three and two, and between groups four and five.

CONCLUSIONS

Beta2-GPI may play a role in the development of HBV-related HCC by activating NF-κB via interaction of beta2-GPI and HBsAg.

Chromogenic in situ hybridization analysis of Epidermal Growth Factor Receptor gene/chromosome 7 numerical aberrations in hepatocellular carcinoma based on tissue microarrays

Although Epidermal Growth Factor Receptor (EGFR) overexpression is observed frequently in hepatocellular carcinomas (HCC), specific gene deregulation mechanisms remain unknown. Our aim was to investigate the prognostic significance of the combined protein and gene/chromosome 7 numerical alterations. Using tissue microarray technology, thirty-five (n = 35) paraffin embedded histologically confirmed HCCs were cored and re-embedded in a paraffin block. Immunohistochemistry was performed for the determination of EGFR protein levels and evaluated by the performance of digital image analysis. Chromogenic in situ hybridization was also performed based on the use of EGFR gene and chromosome 7 centromeric probes, respectively. EGFR overexpression was observed in 26/35 (74.2%) cases and was correlated to the grade of the tumors and also to the history of the patients (p = 0.013, p = 0.036, respectively). Numerical alterations regarding gene and chromosome 7 were identified in 4/35 (11.4%) and 12/35 (43.2%) cases associated to the grade of the tumors (p = 0.019, p = 0.001, respectively) and to the survival rate of the patients (p = 0.037, p = 0.001, respectively). EGFR overall expression was also correlated to the gene copies (p = 0.020). EGFR gene numerical alterations -although rare- and also chromosome 7 aneuploidy maybe affect prognosis in HCC patients. To our knowledge this is the first chromogenic in situ hybridization analysis based on tissue microarrays in hepatocellular carcinoma.

Clinical implication of recurrent copy number alterations in hepatocellular carcinoma and putative oncogenes in recurrent gains on 1q

To elucidate the pathogenesis of hepatocellular carcinoma (HCC) and develop useful prognosis predictors, it is necessary to identify biologically relevant genomic alterations in HCC. In our study, we defined recurrently altered regions (RARs) common to many cases of HCCs, which may contain tumor-related genes, using whole-genome array-CGH and explored their associations with the clinicopathologic features. Gene set enrichment analysis was performed to investigate functional implication of RARs. On an average, 23.1% of the total probes were altered per case. Mean numbers of altered probes are significantly higher in high-grade, bigger and microvascular invasion (MVI) positive tumors. In total, 32 RARs (14 gains and 18 losses) were defined and 4 most frequent RARs are gains in 1q21.1-q32.1 (64.5%), 1q32.1-q44 (59.2%), 8q11.21-q24.3 (48.7%) and a loss in 17p13.3-p12 (51.3%). Through focusing on RARs, we identified genes and functional pathways likely to be involved in hepatocarcinogenesis. Among genes in the recurrently gained regions on 1q, expression of KIF14 and TPM3 was significantly increased, suggesting their oncogenic potential in HCC. Some RARs showed the significant associations with the clinical features. Especially, the recurrent loss in 9p24.2-p21.1 and gain in 8q11.21-q24.3 are associated with the high tumor grade and MVI, respectively. Functional analysis showed that cytokine receptor binding and defense response to virus pathways are significantly enriched in high grade-related RARs. Taken together, our results and the strategy of analysis will help to elucidate pathogenesis of HCC and to develop biomarkers for predicting behaviors of HCC.

Evaluation of serum levels of p53 in hepatocellular carcinoma in Egypt

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-induced death. Somatic mutation of the p53 gene is the most common genetic abnormality so far described in human cancer and there is evidence that supports a high level of p53 alterations in HCC. The aim of this study was to investigate serum levels of p53 in Egyptian patients with HCC, and its relation to other prognostic factors such as tumor grade, alpha-fetoprotein (AFP), and liver function tests in an attempt to clarify their significance in the pathogenesis of the disease. Liver function tests were carried out and AFP and p53 levels were measured for all individuals studied. Our results show that detection of p53 increased the frequency of HCC prediction from 79.5% to 86.3%. Moreover, significant positive correlation between p53 and tumor size (cm) for tumor grade II and III was identified. In conclusion, serum concentration of p53 protein may be a convenient and useful non-invasive screening test for prediction of HCC.

Identification of intrahepatic cholangiocarcinoma related genes by comparison with normal liver tissues using expressed sequence tags

Intrahepatic cholangiocarcinoma (ICC), a malignant tumor derived from the bile duct epithelium, is one of the leading causes of death from cancer, worldwide. However, the mechanisms related to it remain largely unknown. In this study, an analysis of the gene expression profiles for ICC was done using the frequency of the ESTs obtained from nine cDNA libraries that constructed from 4 ICC cell lines and 4 normal liver tissues. One hundred and thirty-seven genes were identified as being either up- or down-regulated in human ICC cells. Thirty genes were randomly selected to confirm their differential expression in 4 human ICC cell lines and 5 ICC tissues compared to normal liver tissues by semi-quantitative RT-PCR. Among these genes, ANXA1, ANXA2, AMBP, and SERPINC1 were further verified by immunohistochemical analyses. In conclusion, these identified genes represent potential biomarkers for ICC and represent potential targets for elucidating the molecular mechanisms that are associated with ICC.

The value of serum CA 19-9 in predicting cholangiocarcinomas in patients with primary sclerosing cholangitis

CA 19-9 has been used with questionable accuracy to aid diagnosis of cholangiocarcinoma complicating primary sclerosing cholangitis. We aimed to characterize the test properties of CA 19-9 and of a change in CA 19-9 over time in predicting cholangiocarcinoma. Charts of 208 patients were reviewed. Fourteen patients had cholangiocarcinoma. Median CA 19-9 was higher with cholangiocarcinoma (15 vs. 290 U/ml, p < 0.0001). A cutoff of 129 U/ml provided: sensitivity 78.6%, specificity 98.5%, adjusted positive predictive value 56.6% and negative predictive value 99.4%. The median change over time was 664 U/ml in cholangiocarcinoma compared to 6.7 U/ml in primary sclerosing cholangitis alone (p < 0.0001). A cutoff of 63.2 U/ml for change in CA 19-9 provided: sensitivity 90%, specificity 98% and positive predictive value 42%. Only 2 patients with cholangiocarcinoma were the candidates for curative therapy. In conclusion, the positive predictive value of an elevated CA 19-9 was 56.6%; only advanced cases were detected by this method.

Nuclear factor-kappaB and liver carcinogenesis

Hepatocellular carcinoma (HCC) is the third deadliest and fifth most common human cancer worldwide. Hepatitis C virus (HCV) and hepatitis B virus (HBV) infections along with alcohol and aflatoxin B1 intake are widely recognized etiological agents in HCCs. It is anticipated that HCCs will constitute a major health problem in the next two decades because of the rising incidence of HCV infections in the US. The poor survival rate achieved by current surgical procedures and chemotherapy treatment has prompted the scientific community to gain a better understanding of the molecular events involved in hepatocarcinogenesis in order to define new targets for more effective treatment. Recent findings from several laboratories have implicated constitutive activation of the transcription factor NF-kappaB as one of the early key events involved in neoplastic progression of the liver. Data is summarized here from recently published studies illustrating a crucial role of NF-kappaB in bridging the action of growth factors and inflammation to hepatic oncogenesis. Although additional work is needed to fully understand the precise role of NF-kappaB in the regulation of the various transitions of HCC development, these new findings raise the intriguing possibility that pharmacologic inhibition of NF-kappaB in the liver could selectively eradicate malignant liver cells without affecting normal liver homeostasis.

Review article: current management of primary sclerosing cholangitis

The management of primary sclerosing cholangitis (PSC) is hindered by incomplete understanding of the pathogenesis of the disease and the lack of good prognostic models. Few large randomized controlled trials of drug therapy have been published. Best practice in the management of PSC is currently based therefore on careful interpretation of the available evidence, close observation of individual patients and clinical experience of the disease. Drug therapy is useful for alleviating symptoms. Ursodeoxycholic acid may slow progression of the disease and reduce the frequency of complications. Consensus is emerging on the issues of screening for the malignant complications of PSC and the indications for liver transplantation are becoming broader and encompassing the earliest stages of cholangiocarcinoma. In view of the rarity of the disease in the general population, large international collaborations to study PSC are necessary to provide clearer answers in areas of uncertainty, and these are now beginning to emerge.

Mutational analysis of BRAF in gallbladder carcinomas in association with K-ras and p53 mutations and microsatellite instability

BACKGROUND

Little is known about the genetic changes involved in the pathogenesis of gallbladder cancer. The aim of this study was to examine the presence of mutations in exon 15 of the B-raf gene to investigate its role in gallbladder carcinogenesis.

MATERIALS AND METHODS

We examined the mutational status in exon 15 of B-raf gene in 21 gallbladder carcinoma specimens and investigated its association with the presence of K-ras and p53 alterations, microsatellite instability and the clinicopathological features of tumors.

RESULTS

B-raf mutations were observed in 7 of 21 (33%) gallbladder carcinomas examined, and all were located at the hot spot codon 599 of exon 15. K-ras and B-raf mutations were never in the same specimens.

CONCLUSIONS

B-raf gene mutations seem to be a quite common event in gallbladder carcinomas, implying that B-raf may play an important role in the pathogenesis of this tumor.

Critical evaluation of the different staging systems for hepatocellular carcinoma

BACKGROUND

Diagnostic and therapeutic options for hepatocellular carcinoma (HCC) have improved substantially in recent years. A number of new palliative and potentially curative treatment strategies are now available. However, evaluation of the therapeutic modalities and assessment of the prognosis of HCC remain difficult owing to the lack of consensus on a single staging system and the availability of a number of new staging systems, each claiming to be the most appropriate.

METHODS

The most frequently used staging systems for HCC are presented here. Their ability to stratify patients into different treatment groups and to define prognosis are discussed. In addition, the advantages and disadvantages of each system are analysed.

RESULTS AND CONCLUSION

None of the currently used staging systems fulfils all the requirements for stratification of patients with HCC into groups of different prognosis and therapeutic recommendations. An international agreement on a single staging system is urgently needed in order to permit comparable randomized clinical trials. Only in this way will the outcome for those with HCC be improved.

The alteration of PTEN tumor suppressor expression and its association with the histopathological features of human primary hepatocellular carcinoma

PURPOSE

Although deletions or inactivating mutations of the tumor suppressor gene PTEN (phosphatase and tensin homolog deleted on chromosome 10) are involved in the development of a variety of tumors including glioblastoma, melanoma, prostate cancer, breast cancer, endometrial cancers etc., the role of PTEN expression in human primary hepatocellular carcinoma (HCC) has not yet been clarified. The aim of this study is to investigate the involvement of PTEN mRNA and protein expression in HCC.

METHODS

The level of PTEN mRNA expression in HCC specimens was analyzed by Northern blot. PTEN poly-clonal antibody was raised by immunizing New Zealand white rabbit with (His)(6)-tagged PTEN fusion protein and characterized by Western blot. The level of PTEN protein expression was determined by immunohistochemistry. The significance of PTEN in HCC was analyzed by comparing its expression level with the clinicopathological parameters of HCC patients.

RESULTS

Four transcripts of PTEN mRNA at 5.5 kb, 4.4 kb, 2.4 kb, and 1.8 kb were detected in most para-carcinoma liver tissues, and the expression level of PTEN mRNA in carcinoma liver tissues was found to decrease significantly. The poly-clonal antibody raised against histidine-tagged fusion PTEN protein showed specific immuno-reactivity to PTEN protein. Using the specific poly-clonal antibody prepared and characterized by ourselves, we found that PTEN protein was significantly down-regulated in HCC tissues compared with paired para-carcinoma tissues. The protein expression of PTEN is negatively associated with the pathological grading and presence of cancer thrombus of HCC.

CONCLUSIONS

Down-regulation of PTEN expression may play an important role in the development of HCC and the level of PTEN expression may be a potential adjuvant parameter in forecasting the progression and prognosis of HCC patients.

Examination of oncogene amplification by genomic DNA microarray in hepatocellular carcinomas: comparison with comparative genomic hybridization analysis

To identify amplified oncogenes involved in hepatocellular carcinomas (HCC), we applied a genomic DNA microarray spotted with 57 oncogenes to 20 HCCs. Aberrations in DNA copy number also were analyzed by comparative genomic hybridization (CGH) using an aliquot of DNA samples. In 5 of 20 HCCs, only 6 oncogenes (CCND1, FGF3/FGF4, SAS/CDK4, TERC, MET, and MYC) were amplified, whereas in the remaining 15 tumors no oncogenes were amplified. A comparison of DNA microarray and conventional CGH analyses showed that, although 5 of 6 amplified oncogenes shown by microarray were located in chromosomal regions shown by CGH to have increased DNA copy numbers, not all genes located in such chromosomal regions were affected. One of the amplified oncogenes (SAS/CDK4) was found in a chromosomal region that was undetected by CGH. We, therefore, conclude that amplification of the oncogenes examined in this series is not directly implicated in hepatocellular carcinogenesis.