Hepatocellular carcinoma (HCC) is the most important primary hepatic cancer and is a common cancer type worldwide. Many aetiological factors have been related to HCC development, such as liver cirrhosis, hepatitis viruses and alcohol consumption. Inactivation of the p53 tumour suppressor gene is one of the most common abnormalities in many tumours, including HCC. p53 is of crucial importance for the regulation of the cell cycle and the maintenance of genomic integrity. In HCC, hepatitis B and C virus (HBV and HCV) effect carcinogenic pathways, independently leading to anomalies in p53 function. Several authors have reported that some HCV proteins, such as the core, NS5A and NS3 proteins, interact with p53 and prevent its correct function. The mechanisms of action of these HCV proteins in relation to p53 are not completely clear, but they might cause its cytoplasmic retention or accumulation in the perinuclear region where the protein is not functional. The identification of the interactions between p53 and HCV proteins is of great importance for therapeutic strategies aimed at reducing the chronicity and/or carcinogenicity of the virus.

Hepatic fibrosis is a wound-healing response to chronic liver injury, which if persistent can lead to cirrhosis and liver failure. Activation of hepatic stellate cells (HSCs), leading to accumulation of extracellular matrix, is the central event of fibrogenesis. Exciting progress has been made in understanding the molecular basis of this process. Major advances include: (1) elucidation of the effects (and signalling pathways) of key cytokines on HSCs; (2) understanding the transcriptional regulation of HSC activation; (3) characterisation of matrix proteases and their inhibitors; (4) demonstration of apoptosis as an important event in the resolution of hepatic fibrosis, and identification of its mediators; (5) elucidation of the complex and dynamic interaction between HSCs and matrix; and (6) understanding the role of other cellular elements in hepatic fibrosis and their interaction with HSCs. Ongoing research with gene analysis using cDNA or oligonucleotide microarrays, or transcriptional profiling, will further increase our knowledge of the regulation of the process. Ultimately, advances in the understanding of the molecular biology of hepatic fibrosis are critical to the development of effective, targeted antifibrotic therapy that might benefit millions of patients with chronic liver disease worldwide.

The generation of transgenic mice with yeast artificial chromosomes (YACs) has proven to be a valuable system to: (1) study gene structure–function relationships; (2) produce mouse models of human disease; (3) complement mouse mutants; (4) generate mice bioreactors; and (5) screen YAC libraries in vivo. Continued refinement of current techniques and development of new protocols should encourage widespread adaptation of this strategy for these and other applications. Use of whole loci as transgenes is an important improvement in murine transgenesis because it results in a more realistic pattern and level of gene expression during ontogeny. Application of this technology to develop human artificial chromosomes (HACs) might provide the next generation of gene therapy vectors that will overcome most of the problems and barriers associated with current vector systems.

Mutation and aberrant expression of the p53 tumour suppressor protein are the most frequent molecular alterations in human malignancy. Peptides derived from the p53 protein and presented by major histocompatibility complex molecules for T-cell recognition could serve as universal tumour-associated antigens for cancer immunotherapy. Because p53 normally functions as a ubiquitously expressed self-protein, controlling cell-cycle progression and apoptosis, it also represents a paradigm target molecule for tumour-reactive yet self-antigen-specific T cells. Tailoring p53-based cancer immunotherapy thus requires both interference with p53-specific self-tolerance and induction of the entire repertoire of p53-reactive T cells. Transferring selected T-cell receptor genes into human T cells offers a novel and appealing strategy to meet these requirements.

Traditional anti-cancer drugs preferentially kill rapidly growing tumour cells rather than normal cells. However, most of these drugs have no preferential selection towards cancer cells and are taken up by the whole body, resulting in significant adverse side effects. Therapeutic molecules that could specifically inhibit undesirable phenotypes are an attractive way of eliminating cancer cells. There is a widespread effort to develop inhibitors against signal transduction molecules that play a key role in the proliferative, migratory and invasive properties of a cancer cell. Grb7 is an adaptor-type signalling protein that is recruited via its Src-homology 2 (SH2) domain to a variety of tyrosine kinases. Grb7 is overexpressed in breast, oesophageal and gastric cancers, and may contribute to the invasive potential of cancer cells. Molecular interactions involving Grb7 therefore provide attractive targets for therapeutic intervention.

Although effective in the short-term, clinical solid-organ transplantation has not achieved its goals as a long-term treatment for patients with end-stage organ failure. Development of so-called chronic transplant dysfunction (CTD) is now recognised as the predominant cause of allograft loss long-term (after the first post-operative year) following transplantation. CTD has the remarkable histological feature that the luminal areas of intragraft arteries become obliterated, predominantly with vascular smooth muscle cells intermingled with some inflammatory cells. The development of this transplant vasculopathy, referred to as transplant arteriosclerosis (TA), is a multifactorial process and many risk factors have been identified. However, the precise pathogenetic mechanisms leading to TA are largely unknown and, as a result, current prevention and treatment protocols are inadequate. This review discusses the risk factors for TA and current views on the pathogenetic mechanisms leading to this vasculopathy. We argue here that host-derived cells contribute to the development of these vascular lesions, and propose that TA results from a normal vascular repair process that proceeds beyond the needs of functional repair. Guided by the proposed sequence of events, we finally discuss possible directions for future intervention strategies to prevent TA after solid-organ transplantation.

The major histocompatibility complex (MHC) harbours genes whose primary function in regulating immune responsiveness to infection is to present foreign antigens to cytotoxic T lymphocytes (CTLs) and T helper cells. In the case of infection by human immunodeficiency virus (HIV), defining the optimal HIV epitopes that are recognised by CTLs is important for vaccine design, and this in turn will depend on the characteristics of the predominant infecting virus. Moreover, the particular MHC human leukocyte antigens (HLAs) expressed by a geographical population is important since these are likely to determine which HIV epitopes are immunodominant in the anti-HIV immune response. Consideration of these aspects has lead to the dawn of a new era of MHC-based vaccine design, in which the CTL epitopes are selected on the basis of the frequency of restricting MHC alleles. This article reviews data on the distribution patterns of molecular subtypes of HLA class I and class II extended haplotypes, discussing distribution among Asian Indians but with reference to global distributions. These data provide a genetic basis for the possible predisposition and fast progression of HIV infections in the Indian population. Since there is selective predominance of different HLA alleles and haplotypes in different populations, a dedicated screening effort is required at the global level to develop MHC-based vaccines against infectious diseases. It is hoped that this might lead to the development of multivalent, poly-epitope, subtype-specific HIV vaccines that are specific for the target geographical location.

Repeat-expansion mutations cause 13 autosomal dominant neurodegenerative disorders falling into three groups. Huntington's disease (HD), dentatorubral pallidoluysian atrophy (DRPLA), spinal and bulbar muscular atrophy (SBMA), and spinocerebellar ataxias (SCAs) types 1, 2, 3, 7 and 17 are each caused by a CAG repeat expansion that encodes polyglutamine. Convergent lines of evidence demonstrate that neurodegeneration in these diseases is a consequence of the neurotoxic effects of abnormally long stretches of glutamines. How polyglutamine induces neurodegeneration, and why neurodegeneration occurs in only select neuronal populations, remains a matter of intense investigation. SCA6 is caused by a CAG repeat expansion in CACNA1A, a gene that encodes a subunit of the P/Q-type calcium channel. The threshold length at which the repeat causes disease is much shorter than in the other polyglutamine diseases, and neurodegeneration may arise from expansion-induced change of function in the calcium channel. Huntington's disease-like 2 (HDL2) and SCAs 8, 10 and 12 are rare disorders in which the repeats (CAG, CTG or ATTCT) are not in protein-coding regions. Investigation into these diseases is still at an early stage, but it is now reasonable to hypothesise that the net effect of each expansion is to alter gene expression. The different pathogenic mechanisms in these three groups of diseases have important implications for the development of rational therapeutics.

Memory is the process by which organisms are able to record their experiences, and use this information to adapt their responses to the environment. As such, it is vital for survival. In recent years, the development of spatially and temporally selective techniques for the regulation of gene expression has allowed the molecular details of this process to emerge. Here we review the molecular mechanisms thought to underlie memory acquisition and storage, as well as discuss recent evidence regarding the mechanisms of subsequent memory consolidation.

Wound healing is a complex process that we have only recently begun to understand. Central to wound repair is transforming growth factor β (TGF-β), a cytokine secreted by several different cell types involved in healing. TGF-β has diverse effects, depending upon the tissue studied. This review focuses on healing in skin, particularly the phases of cutaneous wound repair and the role of TGF-β in normal and impaired wound-healing models. It also explores TGF-β activity in scarless foetal wound healing. Knowledge of TGF-β function in scarless repair is critical to improving healing in clinical scenarios, such as diabetic wounds and hypertrophic scars.

Modern expression-screening platforms such as complementary DNA (cDNA) arrays allow for high-throughput lead discovery in cancer and other diseases. For evaluation of promising candidate genes, however, in situ analysis of high numbers of clinical tissues samples – for example, by immunohistochemistry or fluorescence in situ hybridisation – is mandatory. Tissue microarray (TMA) technology greatly facilitates such analysis. Minute tissue cores (diameter 0.6 mm) are removed from up to a thousand different conventional paraffin blocks and re-assembled in a single empty paraffin block at predefined positions. Sections of the resulting TMA can be utilised for the range of research applicable to conventional tissue sections. Important advantages of the TMA technology are speed (parallel analysis of up to a thousand tissues), cost efficiency (the same amount of reagents required for a single large-section analysis is sufficient for a thousand samples), and standardisation (the same experimental conditions are applied to all samples). Because of the high numbers of samples usually included in TMAs, they are optimally suited to detect genotype–phenotype associations with high statistical power. Thus, TMA technology will markedly accelerate the transition from basic research to clinical applications.

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by a CAG trinucleotide repeat expansion in the HD gene. The expanded repeats are translated into an abnormally long polyglutamine tract close to the N-terminus of the HD gene product (‘huntingtin’). Studies in humans and mouse models suggest that the mutation is associated with a deleterious gain-of-function. Several studies have suggested that the large huntingtin protein is cleaved to produce a shorter N-terminal fragment containing the polyglutamine expansion, and that the polyglutamine expansion causes the protein fragment to misfold and form aggregates (inclusions) in the nuclei and processes of neurons. It is likely that neurotoxicity is caused by the misfolded protein in its soluble form, and/or in aggregates, and/or in the process of aggregation. A wide range of potential mechanisms for neurotoxicity have been proposed, including caspase activation, dysregulation of transcriptional pathways, increased production of reactive oxygen species, and inhibition of proteasome activity. In this review we consider the current status of research in the field and possible mechanisms whereby the HD mutation might result in neurodegeneration.

Retinoblastoma (Rb) is the most common primary ocular malignancy of children and is caused by a mutation in the gene RB1. Approximately 40% of cases are associated with one or more constitutional mutations, and are therefore heritable, whereas the other 60% are sporadic. Rb is exclusively found in young children. In some cases, Rb tumours metastasise to extraocular organs including bone, lung and brain. Although there is no effective treatment for metastatic disease, non-metastatic cases can be cured by removal of the eye (enucleation). Newer treatment strategies emphasise salvaging the affected eye whenever possible. Animal models of Rb have been developed with xenograft and transgenic techniques. Each model has both strengths and weaknesses for exploring the mechanisms of disease development and progression and the efficacy of new treatment strategies.

Toll-like receptors (TLRs) play a principle role in distinct pathogen recognition and in the initiation of innate immune responses of the intestinal mucosa. Activated innate immunity interconnects downstream with adaptive immunity in complex feedback regulatory loops. Intestinal disease might result from inappropriate activation of the mucosal immune system driven by TLRs in response to normal luminal flora.

The pleiotropic nature of the clinical phenotypes of patients with ataxia-telangiectasia (A-T) – which encompass cerebellar degeneration (leading to ataxia), gonadal atrophy, and cancer predisposition – suggests multiple functions of the gene responsible for the disease. The ataxia-telangiectasia mutated gene product (ATM), whose loss of function is responsible for ataxia-telangiectasia, is a protein kinase that interacts with several substrates and is implicated in mitogenic signal transduction, chromosome condensation, meiotic recombination, cell-cycle control and telomere maintenance. This review focuses on the critical roles that ATM appears to play in cell-cycle checkpoints, DNA repair, telomere metabolism and oxidative stress, indicating how defects in these processes might lead to ataxia-telangiectasia.

Medical research continues to illuminate the origins of many human diseases. Gene therapy has been widely proposed as a novel strategy by which this knowledge can be used to deliver new and improved therapies. Viral gene transfer is relatively efficient but there are concerns relating to the use of viral vectors in humans. Conversely, nonviral vectors appear safe but inefficient. Therefore, the development of an efficient nonviral vector remains a highly desirable goal. This review focuses on the numerous challenges preventing efficient nonviral gene transfer in vivo and discusses the many technologies that have been adopted to overcome these problems.

Angiogenesis, the formation of new blood vessels from the pre-existing vasculature, is an integral part of physiological processes such as embryonic development, the female reproductive cycle and wound healing. Angiogenesis is also central to a variety of pathologies including cancer, where it is recognised as being crucial for the growth of solid tumours. Matrix metalloproteinases (MMPs) are a family of soluble and membrane-anchored proteolytic enzymes that can degrade components of the extracellular matrix (ECM) as well as a growing number of modulators of cell function. Several of the MMPs, most notably MMP-2 and -9 and membrane-type-1 MMP (MT1-MMP), have been linked to angiogenesis. Potential roles for these proteases during the angiogenic process include degradation of the basement membrane and perivascular ECM components, liberation of angiogenic factors, production of endogenous angiogenic inhibitors, and the unmasking of cryptic biologically relevant sites in ECM components. This review brings together what is currently known about the functions of the MMPs and the closely related adamalysin metalloproteinase (ADAM) family in angiogenesis, and discusses how this information might be useful in manipulation of the angiogenic process, with a view to controlling aberrant neovascularisation.

Prostate cancer is one of the leading causes of cancer-related death in the USA. In the past decade, tremendous progress has been made in the identification and understanding of the genetic factors related to prostate cancer development. Unlike many other types of cancers, only a small fraction of prostate cancer cases are aggressive and life-threatening. The factors related to prostate cancer development and progression appear complex and diverse. This review summarises some of the important findings in the areas of genome and gene expression abnormalities in prostate cancer, and aims to provide a comprehensive view of new developments in these areas.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used in the treatment of arthritis and pain. However, their long-term use is limited by gastrointestinal (GI) side effects such as gastric ulcers. NSAIDs act by inhibiting an enzyme called cyclooxygenase. Cyclooxygenase (COX) catalyses the generation of prostaglandins from arachidonic acid. Two isoforms of the enzyme exist – COX-1 and COX-2 – both of which are targets for NSAIDs. Although they are associated with GI toxicity, NSAIDs have important antithrombotic and anti-inflammatory effects. The GI injury has been attributed to COX-1 inhibition and the anti-inflammatory effects to COX-2 inhibition. As COX-2 is traditionally viewed as an inducible enzyme, selective inhibition of COX-2 by ‘coxibs’ (selective COX-2 inhibitors) has been employed to achieve anti-inflammatory and analgesic effects without GI side effects. However, recently there have been suggestions that chronic administration of coxibs might increase the risk of cardiovascular events, such as atherosclerosis, compared with traditional NSAIDs. In vascular disease, there is increased expression of both COX-1 and COX-2, resulting in enhanced prostaglandin generation. The specific role of COX-1 and COX-2 in vascular regulation is still unknown but such knowledge is essential for the effective use of coxibs. Although more evidence is pointing to selective COX-1 inhibition as a therapeutic measure in inflammatory atherosclerosis, there are some studies that suggest that inhibition of COX-2 might have a potential benefit on atherosclerosis.

Herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) are ubiquitous human pathogens. They share with other herpesviruses the ability to establish lifelong latent infection of the host. Periodic reactivation from latency is responsible for most of the clinical disease burden of HSV infection. This review focuses on what we have learned from molecular studies in model systems of HSV latency, and the implications these findings have for treating recurrent HSV disease.