EGFR and HER2 expression in advanced biliary tract cancer

AIM:To analyze the pathogenetic role and potential clinical usefulness of the epidermal growth factor receptor(EGFR)and the human epidermal growth factor receptor 2(HER2)in patients with advanced biliary tract cancer(BTC). METHODS:EGFR and HER2 expression was studied in biopsy samples from 124 patients(51%women; median age 64.8 years),with advanced BTC diagnosed between 1997 and 2004.Five micrometers sections of paraffin embedded tissue were examined by standard, FDA approved immunohistochemistry.Tumors with scores of 2+or 3+for HER2 expression on immunochemistry were additionally tested for HER2 gene amplification by fluorescence in situ hybridisation(FISH).RESULTS:34/124 patients(27.4%)had gallbladder cancer,47(37.9%)had intrahepatic BTC and 43(34.7%)had extrahepatic or perihilar BTC.EGFR expression was examined in a subset of 56 samples. EGFR expression was absent in 22/56 tumors(39.3%). Of the remaining samples expression was scored as 1+in 12(21.5%),2+in 13(23.2%)and 3+in 9(16%), respectively.HER2 expression was as follows:score 0 73/124(58.8%),score 1+27/124(21.8%),score 2+ 21/124(17%)and score 3+4/124(3.2%).HER2 gene amplification was present in 6/124,resulting in an overall amplification rate of 5%. CONCLUSION:Our data suggest that routine testing and therapeutic targeting of HER2 does not seem to be useful in patients with BTC,while targeting EGFR may be promising.

Hepatocellular carcinoma: Therapy and prevention

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide. The major etiologies and risk factors for the development of HCC are well defined and some of the multiple steps involved in hepatocarcinogenesis have been elucidated in recent years. Despite these scientific advances and the implementation of measures for the early detection of HCC in patients at risk, patient survival has not improved during the last three decades. This is due to the advanced stage of the disease at the time of clinical presentation and limited therapeutic options. The therapeutic options fall into five main categories: surgical interventions including tumor resection and liver transplantation, percutaneous interventions including ethanol injection and radiofrequency thermal ablation, transarterial interventions including embolization and chemoembolization, radiation therapy and drugs as well as gene and immune therapies. These therapeutic strategies have been evaluated in part in randomized controlled clinical trials that are the basis for therapeutic recommendations. Though surgery, percutaneous and transarterial interventions are effective in patients with limited disease (1-3 lesions, ＜5 cm in diameter) and compensated underlying liver disease (cirrhosis Child A), at the time of diagnosis more than 80% patients present with multicentric HCC and advanced liver disease or comorbidities that restrict the therapeutic measures to best supportive care. In order to reduce the morbidity and mortality of HCC, early diagnosis and the development of novel systemic therapies for advanced disease, including drugs, gene and immune therapies as well as primary HCC prevention are of paramount importance. Furthermore, secondary HCC prevention after successful therapeutic interventions needs to be improved in order to make an impact on the survival of patients with HCC. New technologies, including gene expression profiling and proteomic analyses, should allow to further elucidate the molecular events underlying HCC development and to identify novel diagnostic markers as well as therapeutic and preventive targets.

Interaction of hepatitis C virus envelope glycoprotein E2 with the large extracellular loop of tupaia CD81

AIM: To further analyze the interaction of tupaia CD81 with hepatitis C virus (HCV) envelope protein E2. METHODS: A tupaia CD81 large extracellular loop (CD81 LEL), which binds to HCV E2 protein, was cloned and expressed as a GST-fusion protein, and interaction of HCV E2 protein with a tupaia CD81 LEL was evaluated by enzyme-linked immunosorbent assay (EIA). RESULTS: Although tupaia and human CD81 LEL differed in 6 amino acid changes, tupaia CD81 LEL was strongly recognized by anti-CD81 antibodies against human CD81 LEL conformation-dependent epitopes. Investigating LEL CD81-E2 interactions by EIA, we demonstrated that binding of tupaia CD81 LEL GST fusion protein to recombinant HCV E2 protein was markedly reduced compared to binding of human CD81 LEL GST fusion protein to recombinant HCV E2 protein. CONCLUSION: These data suggest that the structural differences in-between the tupaia and human CD81 may alter the interaction of the large extracellular loop with HCV envelope glycoprotein E2. These findings may be important for the understanding of the mechanisms of binding and entry of HCV to PTHs.

Hepatitis C virus infection and apoptosis

Apoptosis is central for the control and elimination of viral infections. In chronic hepatitis C virus (HCV) infection, enhanced hepatocyte apoptosis and upregulation of the death inducing ligands CD95/Fas, TRAIL and TNFα occur. Nevertheless, HCV infection persists in the majority of patients. The impact of apoptosis in chronic HCV infection is not well understood. It may be harmful by triggering liver fibrosis, or essential in interferon (IFN) induced HCV elimination. For virtually all HCV proteins, pro- and anti-apoptotic effects have been described, especially for the core and NS5A protein. To date, it is not known which HCV protein affects apoptosis in vivo and whether the infectious virions act pro- or anti- apoptotic. With the availability of an infectious tissue culture system, we now can address pathophysiologically relevant issues. This review focuses on the effect of HCV infection and different HCV proteins on apoptosis and of the corresponding signaling cascades.

Pseudomonas exotoxin antisense RNA selectively kills hepatitis B virus infected cells

AIM: To present an approach for selectively killing retrovirus-infected cells that combines the toxicity of Pseudomonas exotoxin (PE) and the presence of reverse transcriptase (RT) in infected cells. METHODS: PE antisense toxin RNA has palindromic stem loops at its 5' and 3' ends enabling self-primed generation of cDNA in the presence of RT. The RT activity expressed in retrovirus-infected cells converts "antisense-toxin-RNA" into a lethal toxin gene exclusively in these cells. RESULTS: Using cotransfection studies with PE-expressing RNAs and β-gal expressing reporter plasmids, we show that, in HepG2 and HepG2.2.15 hepatoma cells as well as in duck hepatitis B virus (DHBV) infected cells, HBV or DHBV-polymerase reverse transcribe a lethal cDNA copy of an antisense toxin RNA, which is composed of sequences complementary to a PE gene and eukaryotic transcription and translation signals. CONCLUSION: This finding may have important implications as a novel therapeutic strategy aimed at the elimination of HBV infection.

Host and viral factors contributing to CD8+ T cell failure in hepatitis C virus infection

Virus-specific CD8+ T cells are thought to be the major anti-viral effector cells in hepatitis C virus (HCV) infection. Indeed, viral clearance is associated with vigorous CD8+ T cell responses targeting multiple epitopes. In the chronic phase of infection, HCV-specific CD8+ T cell responses are usually weak, narrowly focused and display often functional defects regarding cytotoxicity, cytokine production, and proliferative capacity. In the last few years, different mechanisms which might contribute to the failure of HCV-specific CD8+ T cells in chronic infection have been identified, including insufficient CD4+ help, deficient CD8+ T cell differentiation, viral escape mutations, suppression by viral factors, inhibitory cytokines, inhibitory ligands, and regulatory T cells. In addition, host genetic factors such as the host’s human leukocyte antigen (HLA) background may play an important role in the efficiency of the HCV- specific CD8+ T cell response and thus outcome of infection. The growing understanding of the mechanisms contributing to T cell failure and persistence of HCV infection will contribute to the development of successful immunotherapeutical and -prophylactical strategies.

Screening for hepatocellular carcinoma by Egyptian physicians

AIM: To assess the practice of Egyptian physicians in screening patients for hepatocellular carcinoma(HCC). METHODS: The study included 154 physicians from all over Egypt caring for patients at risk for HCC. The study was based on a questionnaire with 20 items. Each questionnaire consisted of two parts:(1) personal information regarding the physician(name, age, specialty and type of health care setting); and(2) professional experience in the care of patients at risk for HCC development(screening, knowledge about the cause and natural course of liver diseases and HCC risk). RESULTS: Sixty-eight percent of doctors with an MD degree, 48% of doctors with a master degree or a diploma and 40% of doctors with a Bachelor of Medicine, Bachelor of Surgery certificate considered the hepatitis C virus(HCV) genotype as risk factor for HCC development(P < 0.05). Ninety percent of physicians specialized in tropical medicine, internal medicine or gastroenterology and 67% of physicians in other specialties advise patients to undergo screening for HCV and hepatitis B virus infection as well as liver cirrhosis(P < 0.05). Eighty-six percent of doctors in University Hospitals and 69% of Ministry of Health(MOH) doctors consider HCV infection as the leading cause of HCC in Egypt(P < 0.05). Seventy-two percent of doctors with an MD degree, 55% of doctors with a master degree or a diploma, 56% of doctors with an MBBCH certificate, 74% of doctors in University Hospitals and 46% of MOH hospital doctors consider abdominal ultrasonography as the most important investigation in HCC screening(P < 0.05). Sixty-five percent of physicians in tropical medicine, internal medicine or gastroenterology and 37% of physicians in other specialties recommend as HCC screening interval of 3 mo(P < 0.05). Seventy-one percent of doctors with an MD degree, 50% of doctors with a master degree or diploma and 60% of doctors with an MBBCH certificate follow the same recommendation.CONCLUSION: In Egypt, physicians specialized in tropical medicine, internal medicine or gastroenterology with an MD degree and working in a University Hospital are best informed about HCC.