Medical Library

Tumor suppressor and hepatocellular carcinoma.

A few signaling pathways are driving the growth of hepatocellular carcinoma. Each of these pathways possesses negative regulators. These enzymes, which normally suppress unchecked cell proliferation, are circumvented in the oncogenic process, either the over-activity of oncogenes is sufficient to annihilate the activity of tumor suppressors or tumor suppressors have been rendered ineffective. The loss of several key tumor suppressors has been described in hepatocellular carcinoma. Here, we systematically review the evidence implicating tumor suppressors in the development of hepatocellular carcinoma.

Martin J, Dufour JF.

Department of Clinical Pharmacology, University of Bern, Murtenstrasse, 35, CH-3010 Bern, Switzerland. juliette.martin@ikp.unibe.ch.

Current role of ultrasound for the management of hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) has a decisive influence on the prognosis of cirrhotic patients. Although alpha-fetoprotein (AFP) is a known and specific tumor maker for HCC, it is not suitable for the screening and surveillance of HCC because of its poor predictive value and low sensitivity. The use of imaging modalities is essential for the screening, diagnosis and treatment of HCC. Ultrasound (US) plays a major role among them, because it provides real-time and non-invasive observation by a simple and easy technique. In addition, US-guided needle puncture methods are frequently required for the diagnosis and/or treatment process of HCC. The development of digital technology has led to the detection of blood flow by color Doppler US, and the sensitivity for detecting tumor vascularity has shown remarkable improvement with the introduction of microbubble contrast agents. Moreover, near real-time 3-dimensional US images are now available. As for the treatment of HCC, high intensity focused ultrasound (HIFU) was developed as a novel technology that provides transcutaneous ablation effect without needle puncture. These advancements in the US field have led to rapid progress in HCC management, and continuing advances are expected. This article reviews the current application of US for HCC in clinical practice.

Maruyama H, Yoshikawa M, Yokosuka O.

Department of Medicine and Clinical Oncology, Chiba University Graduate School of Medicine 1-8-1, Inohana, Chuou-ku, Chiba 260-8670, Japan. maru-cib@umin.ac.jp.

Activins and activin antagonists in hepatocellular carcinoma.

In many parts of the world hepatocellular carcinoma (HCC) is among the leading causes of cancer-related mortality but the underlying molecular pathology is still insufficiently understood. There is increasing evidence that activins, which are members of the transforming growth factor beta (TGFbeta) superfamily of growth and differentiation factors, could play important roles in liver carcinogenesis. Activins are disulphide-linked homo- or heterodimers formed from four different beta subunits termed betaA, betaB, betaC, and betaE, respectively. Activin A, the dimer of two betaA subunits, is critically involved in the regulation of cell growth, apoptosis, and tissue architecture in the liver, while the hepatic function of other activins is largely unexplored so far. Negative regulators of activin signals include antagonists in the extracellular space like the binding proteins follistatin and FLRG, and at the cell membrane antagonistic co-receptors like Cripto or BAMBI. Additionally, in the intracellular space inhibitory Smads can modulate and control activin activity. Accumulating data suggest that deregulation of activin signals contributes to pathologic conditions such as chronic inflammation, fibrosis and development of cancer. The current article reviews the alterations in components of the activin signaling pathway that have been observed in HCC and discusses their potential significance for liver tumorigenesis.

Deli A, Kreidl E, Santifaller S, Trotter B, Seir K, Berger W, Schulte-Hermann R, Rodgarkia-Dara C, Grusch M.

Department of Medicine I, Division: Institute of Cancer Research, Medical University of Vienna, Borschkegasse 8a, Vienna A-1090, Austria. michael.grusch@meduniwien.ac.at.

Reactivation of the insulin-like growth factor-II signaling pathway in human hepatocellular carcinoma.

Constitutive activation of the insulin-like growth factor (IGF)-signaling axis is frequently observed in human hepatocellular carcinoma (HCC). Especially the overexpression of the fetal growth factor IGF-II, IGF-I receptor (IGF-IR), and cytoplasmic downstream effectors such as insulin-receptor substrates (IRS) contribute to proliferation, anti-apoptosis, and invasive behavior. This review focuses on the relevant alterations in this signaling pathway and independent in vivo models that support the central role IGF-II signaling during HCC development and progression. Since this pathway has become the center of interest as a target for potential anti-cancer therapy in many types of malignancies, various experimental strategies have been developed, including neutralizing antibodies and selective receptor kinase inhibitors, with respect to the specific and efficient reduction of oncogenic IGF-II/IGF-IR-signaling.

Breuhahn K, Schirmacher P.

Institute of Pathology, University Hospital of Heidelberg, Heidelberg 69120, Germany. kai.breuhahn@med.uni-heidelberg.de.

Is human hepatocellular carcinoma a hormone-responsive tumor?

Before the positive results recently obtained with multitarget tyrosine kinase inhibitor sorafenib, there was no standard systemic treatment for patients with advanced hepatocellular carcinoma (HCC). Sex hormones receptors are expressed in a significant proportion of HCC samples. Following preclinical and epidemiological studies supporting a relationship between sex hormones and HCC tumorigenesis, several randomized controlled trials (RCTs) tested the efficacy of the anti-estrogen tamoxifen as systemic treatment. Largest among these trials showed no survival advantage from the administration of tamoxifen, and the recent Cochrane systematic review produced a completely negative result. This questions the relevance of estrogen receptor-mediated pathways in HCC. However, a possible explanation for these disappointing results is the lack of proper patients selection according to sex hormones receptors expression, but unfortunately the interaction between this expression and efficacy of tamoxifen has not been studied adequately. It has been also proposed that negative results might be explained if tamoxifen acts in HCC via an estrogen receptor-independent pathway, that requires higher doses than those usually administered, but an Asian RCT conducted to assess dose-response effect was completely negative. Interesting, preliminary results have been obtained when hormonal treatment (tamoxifen or megestrol) has been selected according to the presence of wild-type or variant estrogen receptors respectively, but no large RCTs are available to support this strategy. Negative results have been obtained also with anti-androgen therapy. In conclusion, there is no robust evidence to consider HCC a hormone-responsive tumor. Hormonal treatments should not be part of the current management of HCC.

Di Maio M, Daniele B, Pignata S, Gallo C, De Maio E, Morabito A, Piccirillo MC, Perrone F.

Clinical Trials Unit, National Cancer Institute, Via M.Semmola, Napoli 80131, Italy. fr.perrone@agora.it.

Harnessing the RNA interference pathway to advance treatment and prevention of hepatocellular carcinoma.

Primary liver cancer is the fifth most common malignancy in the world and is a leading cause of cancer-related mortality. Available treatment for hepatocellular carcinoma (HCC), the commonest primary liver cancer, is rarely curative and there is a need to develop therapy that is more effective. Specific and powerful gene silencing that can be achieved by activating RNA interference (RNAi) has generated enthusiasm for exploiting this pathway for HCC therapy. Many studies have been carried out with the aim of silencing HCC-related cellular oncogenes or the hepatocarcinogenic hepatitis B virus (HBV) and hepatitis C virus (HCV). Proof of principle studies have demonstrated promising results, and an early clinical trial assessing RNAi-based HBV therapy is currently in progress. Although the data augur well, there are several significant hurdles that need to be overcome before the goal of RNAi-based therapy for HCC is realized. Particularly important are the efficient and safe delivery of RNAi effecters to target malignant tissue and the limitation of unintended harmful non-specific effects.

Arbuthnot P, Thompson LJ.

Antiviral Gene Therapy Research Unit, Department of Molecular Medicine and Haema-tology, University of the Witwatersrand Medical School, Private Bag 3, WITS 2050, South Africa. patrick.arbuthnot@wits.ac.za.

Radioembolization for the treatment of unresectable hepatocellular carcinoma: A clinical review.

Hepatocellular carcinoma (HCC) is the sixth most common cancer in the world. The majority of patients with HCC present with unresectable disease. These patients have historically had limited treatment options secondary to HCC demonstrating chemoresistance to the currently available systemic therapies. Additionally, normal liver parenchyma has shown intolerance to tumoricidal radiation doses, limiting the use of external beam radiation. Because of these limitations, novel percutaneous liver-directed therapies have emerged. The targeted infusion of radioactive microspheres (radioembolization) represents one such therapy. Radioembolization is a minimally invasive transcatheter therapy through which radioactive microspheres are infused into the hepatic arteries that supply tumor. Once infused, these microspheres traverse the hepatic vascular plexus and selectively implant within the tumor arterioles. Embedded within the arterioles, the (90)Y impregnated microspheres emit high energy and low penetrating radiation doses selectively to the tumor. Radioembolization has recently shown promise for the treatment of patients with unresectable HCC. The objective of this review article is to highlight two currently available radioembolic devices ((90)Y, (188)Rh) and provide the reader with a recent review of the literature.

Ibrahim SM, Lewandowski RJ, Sato KT, Gates VL, Kulik L, Mulcahy MF, Ryu RK, Omary RA, Salem R.

Interventional Oncology, Department of Radiology, Section of Interventional Radiology, Northwestern University Feinberg School of Medicine, 676 North St. Clair Street, Suite 800, Chicago 60611, United States. r-salem@northwestern.edu.

Hepatocellular carcinoma, human immunodeficiency virus and viral hepatitis in the HAART era.

The incidence of hepatocellular carcinoma (HCC) in patients with human immunodeficiency virus (HIV) is rising. HCC in HIV almost invariably occurs in the context of hepatitis C virus (HCV) or hepatitis B virus (HBV) co-infection and, on account of shared modes of transmission, this occurs in more than 33% and 10% of patients with HIV worldwide respectively. It has yet to be clearly established whether HIV directly accelerates HCC pathogenesis or whether the rising incidence is an epiphenomenon of the highly active antiretroviral therapy (HAART) era, wherein the increased longevity of patients with HIV allows long-term complications of viral hepatitis and cirrhosis to develop. Answering this question will have implications for HCC surveillance and the timing of HCV/HBV therapy, which in HIV co-infection presents unique challenges. Once HCC develops, there is growing evidence that HIV co-infection should not preclude conventional therapeutic strategies, including liver transplantation.

Macdonald DC, Nelson M, Bower M, Powles T.

St Bartholomew’s Hospital, Department of Medical Oncology, London, United Kingdom. thomas.powles@bartsandthelondon.nhs.uk.

Natural history of hepatitis-related hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is an important cause of cancer death in the world. It has great regional differences in the pathology and epidemiology. The variation is greatly influenced by the aetiologies of the disease. Hepatitis B and C infection are the most important risk factors. HCC incidence rates are higher but in decreasing trend in developing countries. However, the figures in the developed countries are contrary. Successful hepatitis B virus (HBV) vaccination programs, better food hygiene, increased global hepatitis C virus (HCV) prevalence and population migration are the possible explanations. A number of clinical and pathogenic differences exist between HBV- and HCV-related HCC. HBV infection leads to the development of HCC through direct and indirect pathways as it has the ability to integrate into the host genome affecting cellular signaling and growth control. HCV causes HCC mainly through indirect pathways: chronic inflammation, cell deaths and proliferation. As a result, HCC is almost exclusively found in cirrhotic HCV patients while HCC is sometimes found in HBV patients without significant liver cirrhosis. Due to the different severities of liver cirrhosis and HCC extent, therapeutic strategies from resection, liver transplantation to symptoms palliation are available. Poorly differentiated histology, lack of fibrous capsule, large tumour size, early vascular invasion and elevated serum levels of alpha fetoprotein (AFP) are the features for more aggressive disease. Combined with markers of liver reserve and performance status, accurate scoring systems and models have been developed to predict patientso survival and match best treatment option.

But DY, Lai CL, Yuen MF.

Department of Medicine, the University of Hong Kong, Queen Mary Hospital, Pokfulam Road, Hong Kong, China. mfyuen@hkucc.hku.hk.

Gastric cancer: Animal studies on the risk of hypoacidity and hypergastrinemia.

Gastric hypoacidity and hypergastrinaemia are seen in several conditions associated with an increased risk of gastric malignancy. Hypoacidity and hypergastrinaemia are closely related and their long-term effects are difficult to study separately in patients. Studies using animal models can provide valuable information about risk factors and mechanisms in gastric cancer development as the models allow a high degree of intervention when introducing or eliminating factors possibly affecting carcinogenesis. In this report, we briefly review findings from relevant animal studies on this topic. Animal models of gastric hypoacidity and hypergastrinaemia provide evidence hypergastrinaemia is a common causative factor in many otherwise diverse settings. In all species where sufficient hypoacidity and hypergastrinaemia have been induced, a proportion of the animals develop malignant lesions in the gastric oxyntic mucosa.

Fossmark R, Qvigstad G, Waldum HL.

Department of Gastroenterology and Hepatology. St. Olav’s Hospital, Olav Kyrres gate 17, Trondheim 7006, Norway. reidar.fossmark@ntnu.no.