Human papillomavirus 16 (HPV16) infection is the aetiologic factor for the development of cervical dysplasia and is regarded as highly carcinogen, because it is implicated in more than 50% of cervical cancer cases, worldwide. The tumourigenic potential of HPV16 has triggered the extensive sequence analysis of viral genome in order to identify nucleotide variations and amino acid substitutions that influence viral oncogenicity and subsequently the initiation and progression of cervical cancer. Nowadays, specific mutations of HPV16 DNA have been associated with an increased risk of high-grade squamous intraepithelial lesions and invasive cervical cancer (ICC) development, including E6: Q14H, H78Y, L83V, Ε7: N29S, S63F, E2: H35Q, P219S, T310K, E5: I65V, whereas highly conserved regions of viral DNA have been extensively characterised. In addition, numerous novel HPV16 mutations are observed among the studied populations from various geographic regions, hence advocating that different HPV16 strains seem to emerge with different tumourigenic capacities. The present review focuses on the variability of the early genes and the long control region, emphasising on the association of specific mutations with the development of severe dysplasia. Finally, it evaluates whether specific regions of HPV16 DNA are able to serve as valuable biomarkers for cervical cancer risk.

We hypothesize that forms of antagonistic coevolution have forged strong links between positive selection at the molecular level and increased cancer risk. By this hypothesis, evolutionary conflict between males and females, mothers and foetuses, hosts and parasites, and other parties with divergent fitness interests has led to rapid evolution of genetic systems involved in control over fertilization and cellular resources. The genes involved in such systems promote cancer risk as a secondary effect of their roles in antagonistic coevolution, which generates evolutionary disequilibrium and maladaptation. Evidence from two sources: (1) studies on specific genes, including SPANX cancer/testis antigen genes, several Y-linked genes, the pem homebox gene, centromeric histone genes, the breast cancer gene BRCA1, the angiogenesis gene ANG, cadherin genes, cytochrome P450 genes, and viral oncogenes; and (2) large-scale database studies of selection on different functional categories of genes, supports our hypothesis. These results have important implications for understanding the evolutionary underpinnings of cancer and the dynamics of antagonistically-coevolving molecular systems.

Upper gastrointestinal (GI) tract malignancies, including carcinomas of the esophagus, the GI junction and the stomach, are among the most common cancers worldwide. Overall survival is poor because many patients present with locally advanced and often incurable disease. This review focuses on the pathogenesis of adenocarcinomas of the stomach. It summarises recent findings on genetic predisposition to gastric cancer, in particular in relation to germline mutations in the E-cadherin gene. It also describes the molecular basis of sporadic gastric cancer, including alterations in oncogenes, tumour suppressor genes and growth factors, and discusses how these findings might be used in the clinic for improved diagnosis and therapy.

Some six or so physiological systems, essential to normal mammalian life, are involved in poisoning; an intoxication that causes severe injury to any one of them could be life threatening. Reversible chemical reactions showing Scatchard-type binding are exemplified by CO, CN− and cyclodiene neurotoxin insecticide intoxications, and by antigen–antibody complex formation. Haemoglobin (Hb) molecular biology accounts for the allosteric co-operativity and other characteristics of CO poisoning, CN− acts as a powerful cytochrome oxidase inhibitor, and antigen binding in a deep antibody cleft between two domains equipped with epitopes for antigen-binding groups explains hapten-specific immune reactions. Covalent chemical reactions with second-order (SN2) kinetics characterize Hg and Cd poisonings, the reactions of organophosphates and phosphonates with acetylcholinesterase and neurotoxic esterase and the reaction sequence whereby Paraquat accepts electrons and generates superoxide under aerobic conditions. Indirect carcinogens require cytochrome P450 activation to form DNA adducts in target-organ DNA and cause cancer, but a battery of detoxifying enzymes clustered with the P450 system must be overcome. Thus, S-metabolism competes ineffectively with target DNA for reactive vinyl chloride (VC) metabolites, epoxide hydrolase is important to the metabolism and carcinogenicity of aflatoxins and polycyclic aromatic hydrocarbons (benzo[a]pyrene, etc.), and the non-toxic 2-naphthylhydroxylamine N-glucuronide acts as a transport form in 2-naphthylamine bladder cancer. VC liver-cancer pathogenesis is explicable in terms of the presence of the glutathione S-transferase detoxifying system in hepatocytes and its absence from the fibroblastic elements, and of the VC concentrations reaching the liver by different administrative routes. In VC carcinogenicity, chemical reactions give imidazo-cyclization products with nucleoside residues of target DNA, and in benzene leukaemia, Z,Z-muconaldehyde forms cyclic products containing a pyrrole residue linked to purine. Increased HbCO concentrations reduce the O2-carrying capacity of the blood, and the changed shape of the O2-Hb dissociation curve parallels disturbance in O2 unloading. CN− acts on electron transport and paralyses respiration. In telodrin poisoning, preconvulsive glutamine formation abstracts tricarboxylic acid intermediates incommensurately with normal cerebral respiration. Antigen–antibody complexing depletes the antibody titre, available against infection. At high doses of Cd, Cd-thionein filtered through the kidneys is reabsorbed and tubular lesions produced. Some organophosphate insecticides promote irreversible acetylcholinesterase phosphorylation and blockade nerve function, and others react with neurotoxic esterase to cause delayed neuropathy. The evidence for Paraquat pulmonary poisoning suggests a radical mechanism involving three interrelated cyclic reaction stages. The action of N- and O6 (O substituent in 6-position of the purine) demethylases explains deletion mechanisms for DNA-alkyl adducts. DNA-directed synthesis in the presence of ultimate carcinogens provides for an estimation of misincorporations, which implicate the same transversions as those found by direct mutagenicity testing. Chemical carcinogens recognize tissue-sensitive cells and modify their heritable genetic complement. Oncoproteins encoded by activated oncogenes signal the transformation of normal cells into cancer cells. The importance of the H-ras oncogene and p53 tumour-suppressor gene is stressed. Antidotal action is analysed; for example, parenteral glutamine administration to telodrin-intoxicated rats restores the depleted cerebral glutamate level and prevents seizures. Glutamate acts as anticonvulsant in petit mal epilepsy. In general, therefore, the reaction of the toxicant-related substance with the relevant target-tissue macromolecule accounts for the biochemical/biological events at a cellular level and also the symptoms in the living mammal. This mechanism is analogous to mechanisms for diseases such as arthritis and Parkinsonism.

To evaluate the predictive role of the oncogenes p53, MDM-2 and cyclin D1, and the proliferative marker Ki67, in the progression from low-grade dysplasia to carcinoma of the larynx. We studied immunohistochemically a series of 32 low-grade pre-neoplastic laryngeal lesions, 10 of which progressed to invasive carcinoma. Immunoreactivity in more than 10 per cent of the dysplastic cells was detected in five cases immunostained with anti-p53 (≈ 15 per cent), in two with anti-MDM-2 (≈ six per cent), and 11 with anti-Ki67 antibodies (≈ 34 per cent), whereas none of the cases showed cyclin D1 overexpression. No significant association was found between p53 and MDM-2 immunoreactivity and the evolution to carcinoma; on the contrary, Ki67 expression was detectable in all but one of the 10 cases developing an infiltrative tumour (90 per cent), and in two of the 22 cases that did not progress (≈ nine per cent) (p = 0.01). These findings indicate that immunohistochemical assessment of the proliferative index in bioptic samples of dysplastic laryngeal mucosa may be useful in selecting patients who should undergo a more specific follow-up evaluation.

We consider a study of MZ and DZ twin pairs ascertained because one or both twins have a disease. Genotypes at a major locus are known and putative environmental risk factors have been measured for all individuals. The power of the study to estimate the effect on liability of the measured and residual genetic and environmental effects (Gm, Gr, Em, Er) and all two-way interactions between them (except Gr × Er) is estimated by simulation. If liabilities can be indexed on a continuous scale (eg, blood pressure as an index of liability to hypertension), then a study of 600 MZ and 600 DZ pairs would have sufficient power to detect quite subtle interaction effects, even if ascertainment is greatly biased toward MZ twins. If liabilities cannot be measured and only affection status is known, then the power of the study would be much lower, although not impracticably so. There appears to be no advantage in augmenting the twins with a sample of control individuals who have been drawn at random from the population regardless of disease status, at least for the case we have considered in which the disease threshold on the liability scale is assumed to be known without error. The argument is developed in terms of the utility of the design for research into breast cancer.