Environmental causes of human cancers

Reporting multitargeted potency of Tiaprofenic acid against lung cancer: Molecular fingerprinting, MD simulation, and MTT-based cell viability assay studies

Lung Cancer (LC) is among the most death-causing cancers, has caused the most destruction and is a gender-neutral cancer, and WHO has kept this cancer on its priority list to find the cure. We have used high-throughput virtual screening, standard precision docking, and extra precise docking for extensive screening of Drug Bank compounds, and the uniqueness of this study is that it considers multiple protein targets of prognosis and metastasis of LC. The docking and MM\GBSA calculation scores for the Tiaprofenic acid (DB01600) against all ten proteins range from -8.422 to -5.727 kcal/mol and - 47.43 to -25.72 kcal/mol, respectively. Also, molecular fingerprinting helped us to understand the interaction pattern of Tiaprofenic acid among all the proteins. Further, we extended our analysis to the molecular dynamic simulation in a neutralised SPC water medium for 100 ns. We analysed the root mean square deviation, fluctuations, and simulative interactions among the protein, ligand, water molecules, and protein-ligand complexes. Most complexes have shown a deviation of <2 Å as cumulative understanding. Also, the fluctuations were lesser, and only a few residues showed the fluctuation with a huge web of interaction between the protein and ligand, providing an edge that supports that the protein and ligand complexes were stable. In the MTT-based Cell Viability Assay, Tiaprofenic Acid exhibited concentration-dependent anti-cancer efficacy against A549 lung cancer cells, significantly reducing viability at 100 μg/mL. These findings highlight its potential as a therapeutic candidate, urging further exploration into the underlying molecular mechanisms for lung cancer treatment.

A configurable computer simulation model for reducing patient waiting time in oncology departments

Nowadays, the increase in patient demand and the decline in resources are lengthening patient waiting times in many chemotherapy oncology departments. Therefore, enhancing healthcare services is necessary to reduce patient complaints. Reducing the patient waiting times in the oncology departments represents one of the main goals of healthcare managers. Simulation models are considered an effective tool for identifying potential ways to improve patient flow in oncology departments. This paper presents a new agent-based simulation model designed to be configurable and adaptable to the needs of oncology departments which have to interact with an external pharmacy. When external pharmacies are utilised, a courier service is needed to deliver the individual therapies from the pharmacy to the oncology department. An oncology department located in southern Italy was studied through the simulation model and different scenarios were compared with the aim of selecting the department configuration capable of reducing the patient waiting times.

Experimental Evaluation of the Effectiveness of Resveratrol as an Antioxidant in Colon Cancer Prevention

According to the WHO, cancer is the second leading cause of death globally and the third most common cancer is colorectal. A significant etiological factor for carcinogenesis might be oxidative stress. Chemoprevention by consuming natural antioxidants has great perspectives in the struggle to control cancer because it is available and affordable for the wide population. Studies by diverse research groups discovered that grapes, as well as grape-based products, are exceptional sources of the polyphenolic compound resveratrol, which has powerful antioxidant properties. Despite the great number of publications on the anticancer effectiveness of resveratrol, they were all aimed at studying its action once the condition was established. This experiment was the first to study the dynamics of the anticancer activity of resveratrol in the development of chemically induced colorectal cancer. Administrating resveratrol along with 1,2-dimethylhydrazine (DMH) during 30 weeks led to the inhibition of oxidative stress manifestations, in particular, lipid peroxidation. Our research showed that the level of thiobarbituric acid reactive substances in blood serum was 85.1%, 214.6%, and 276.9% lower on the third, fifth, and seventh months of the experiment in the group of rats that obtained resveratrol, compared with the animals affected only by DMH. In the fifth month of the experiment, we noticed that the GPx activity in blood serum was 1.54 times higher than the DMH-control level. During the next 8 weeks, this indicator decreased. The activity of glutathione reductase increased by 2 times in the seventh month, compared with the DMH-control. Histologically resveratrol decelerated the development of the tumor. After 30 weeks of experiment, rats that were receiving only DMH had developed colon adenocarcinoma in situ. In contrast to them, morphological changes in the colon tissue of the animals that obtained resveratrol + DMH could be characterized as signs of mucous colitis.

Association of CD14 gene -260C>T and -561C>T polymorphisms with cancer susceptibility: A meta-analysis

BACKGROUND

Two polymorphisms, -260C>T (rs2569190) and -561C>T (rs5744455), in the CD14 gene have been implicated in susceptibility to cancer. However, the results remain inconclusive. The current meta-analysis was carried out aiming to confirm the function of these two polymorphisms on the susceptibility of cancer.

METHODS

We collected eligible studies from databases, including PubMed, EMBASE, CNKI, Wanfang, and VIP (Weipu). We used logistic regression calculation to compute odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

After strict selection, 24 studies with 5854 cases and 10339 controls for -260C>T and seven studies with 1809 cases and 7289 controls for -561C>T were finally enlisted into our analysis reference material. Pool results revealed that neither -260C>T, nor -561C>T was found to have any association with overall cancer susceptibility. Nevertheless, when stratified by cancer type, we detected a decreased risk associated with other cancers in a heterozygous model (OR = 0.69, 95% CI = 0.51-0.93, p = 0.014) and a dominant model (OR = 0.70, 95% CI = 0.53-0.93, p = 0.012) for -561C>T. An increased risk was found in other cancers under an allele model (OR = 1.29, 95% CI = 1.03-1.62, p = 0.026), in laryngeal cancer under a dominant model (OR = 1.38, 95% CI = 1.11-1.71, p = 0.003) and for a score ≤ 9 under a recessive model (OR = 1.45, 95% CI = 1.09-1.91, p = 0.009) for -561C>T.

CONCLUSIONS

In the present study, we conclude that the CD14 -260C>T and -561C>T polymorphisms might not be associated with overall cancer risk. Further studies are encouraged to confirm this conclusion.

Spatial distribution characteristics of tumor marker CA724 reference values in China

Objects

This study aims to explore the Cancer antigen 724 (CA724) reference values spatial distribution characteristics in healthy Chinese adults. The study can provide regional reference for medical diagnosis.

Study Design

The relationship between CA724 and 25 geographical environmental factors was analyzed firstly. Artificial neural network simulation training was used to construct the prediction model. The national forecast distribution map of the CA724 reference values was obtained by the geostatistical mapping method. Analyzing and exploring the influence mechanism of geographical environment factors on CA724 reference values.

Methods

Collecting 34470 cases from more than 106 cities healthy adults CA724 reference values via several paper databases in 10 recent years. Correlation analysis, RBF artificial neural networks and trend surface analysis were applied to explore if there was any tendency of spatial variation. The Kriging interpolation of geostatistical analysis was developed to reveal the spatial distribution characteristics of the CA724 reference values.

Results

The distribution of CA724 reference values of Chinese healthy adults shows a downward trend from south to north. CA724 reference values have negative correlations with latitude, annual sunshine duration and topsoil cation exchange capacity in clay. CA724 have positive correlations with annual mean air temperature, annual mean relative humidity, and annual precipitation amount. High temperature and high humidity environment will reduce gastrointestinal function and breeze various mold bacteria. Lack of sunshine can easily lead to vitamin C deficiency in the body. These will increase the incidence of gastrointestinal diseases and gastric cancer, then increase the CA724 value.

Conclusion

CA724 reference values show spatial autocorrelation and regional variation. There are some geographical environment factors effected Chinese healthy adults CA724 reference values. Geographic factors such as sunshine, temperature, and humidity have effects on CA724 reference values can provide new ideas and directions of prevention and clinical diagnosis in the future.

Adherence to Dietary Approaches to Stop Hypertension (DASH)-Style Diet and the Risk of Cancer: A Systematic Review and Meta-Analysis of Cohort Studies

Objective: Several investigators have proposed a protective association between dietary approaches to stop hypertension (DASH) style diet and risk of cancers; however, they have had inconsistent results. The present study aimed to systematically review the prospective cohort studies and if possible quantify the overall effect using meta-analysis. Methods: PubMed, Scopus, and Google Scholar were searched for cohort studies published up to July 2018. Relative risks (RRs) that were reported for fully adjusted models and their confidence intervals were extracted for meta-analysis. The random effects model was used to combine the RRs. Results: Seventeen studies were eligible to be included in the systematic review, from which nine reports assessed the association between the DASH diet and risk of mortality from all cancer types, four assessed incidence of colorectal cancer, and two studies assessed the risk of colon and rectal cancer separately. Four studies examined the association with the incidence of other cancers (breast, hepatic, endometrial, and lung cancer). Meta-analysis showed that high adherence to DASH is associated with a decreased mortality from all cancer types (RR = 0.84, 95% confidence interval [95%CI]: 0.81-0.86). Participants with the highest adherence to the DASH diet had a lower risk of developing colorectal (RR = 0.79, 95%CI: 0.75-0.83), colon (RR = 0.80, 95%CI: 0.74-0.87), and rectal (RR = 0.84, 95%CI: 0.74-0.96) cancers compared to those with the lowest adherence. Conclusion: DASH-style diet should be suggested as a healthy approach associated with decreased risk of cancer in the community. Prospective studies exploring the association for other cancer types and from regions other than the United States are highly recommended.

Cancer and how the patients see it; prevalence and perception of risk factors: a cross-sectional survey from a tertiary care centre of Karachi, Pakistan

BACKGROUND

The incidence of cancer is rising but data available regarding prevalence of cancer and patient perception of the disease in Pakistan is limited. It is difficult to deal with Cancer if the main causes are negligence towards risk factors and bizarre myths. This study was aimed to investigate common cancer presentations at a government sector hospital and to gain insight into patient knowledge of the disease.

METHODS

This was a cross-sectional study conducted on cancer patients from Jinnah Postgraduate Medical Centre. A self-made questionnaire was used to assess the norms related to cancer prevalence in our society, associated myths, and the most common risk factors per them.

RESULTS

A total of 402 participants consented to participate in the study (mean age 42.3 ± 15.07 years), 204(50.7%) were females and 190(47.3%) were illiterate. Biomass exposure was found in 147(37%), drug abuse in 132(33%) and smoking in 63(16%). We found 103(25.6%) had positive family histories of cancer. The most common primary tumor site was breast for females 98(48%) and Head and neck 66(33.3%) for males. Patients considered fate 328(82%), gutka 284(71%) and injuries 282(70%) as the most common causes for cancer; while 222(55.5%) considered black magic and 236(58.75%) considered evil eye as a risk factor for cancer. Cancer treatment caused significant financial stress in 376(93.5%) patients.

CONCLUSION

Breast and head and neck cancers were found to be prevalent among patients. It was noted that patients are negligent in daily life regarding the consumption of substances that commonly cause cancer. Individuals had diminished knowledge and majority linked cancer to unrelated causes and myths like black magic and fate. Almost all the patients complained of severe financial stress imposed by the disease.

Italian General Practitioners and Smoking Cessation Strategies

Aims and Background

General practitioners (GPs) are in a key position to intervene with patients who smoke. The cornerstone of a smoking cessation strategy should be the routine provision of brief advice and follow-up in primary care. However, it seems GPs do not often take action against smoking, at least in Italy as shown by previous reports. The survey was planned, in the context of the “GPs Empowerment Project”, a collaborative project involving Denmark, France, Greece, Italy and Portugal, under the ENSP contract with the European Commission (Health & Consumer protection Directorate-General), to evaluate the general attitude, knowledge and behavior of GPs regarding smoking cessation methods.

Methods

A total of 729 family doctors, 409 in Northern and 320 in Southern Italy, were interviewed by phone in the period July-October 2000 regarding their personal smoking habits and their approach with patients on the topic. Prevalence rates were computed using the Epi INFO 6.0 software and were presented as the unadjusted percentage prevalence.

Results

The percentage of current smokers among GPs included in the survey was 28.3%, with a higher prevalence in the south (33.3%). Most of the GPs believe that it is their duty to give information about smoking cessation (96.8%) and consider giving information about smoking cessation to their patients an important intervention (98.5%), but only about 49% think their patients will accept their advice. Most GPs (87.3%) declared having discussed about tobacco use with their patients during the month preceding the interview, and 83.5% would like to be trained on smoking cessation strategies.

Conclusions

The results show that, in order to implement primary prevention in clinical practice in Italy, it appears essential to reduce the number of GPs who smoke and to improve GP training on smoking cessation procedures.

Non‑infective occupational risk factors for hepatocellular carcinoma: A review (Review)

Liver cancer is the second leading worldwide cause of cancer‑associated mortalities. Hepatocellular carcinoma, which accounts for the majority of liver tumors, ranks fifth among types of human cancer. Well‑established risk factors for liver cancer include the hepatitis B and C viruses, aflatoxins, alcohol consumption, and oral contraceptives. Tobacco smoking, androgenic steroids, and diabetes mellitus are suspected risk factors. Current knowledge regarding non‑infective occupational risk factors for liver cancer is inconclusive. The relevance of liver disorders to occupational medicine lies in the fact that the majority of chemicals are metabolized in the liver, and toxic metabolites generated via metabolism are the predominant cause of liver damage. However, their non‑specific clinical manifestations that are similar in a number of liver diseases make diagnosis difficult. Furthermore, concomitant conditions, such as viral hepatitis and alcohol or drug abuse, may mask liver disorders that result from occupational hepatotoxic agents and block the demonstration of an occupational cause. The identification of environmental agents that result in human cancer is a long and often difficult process. The purpose of the present review is to summarize current knowledge regarding the association of non‑infective occupational risk exposure and HCC, to encourage further research and draw attention to this global occupational public health problem.

Molecular epidemiology of acute leukemia in children: causal model, interaction of three factors-susceptibility, environmental exposure and vulnerability period

Acute leukemias have a huge morphological, cytogenetic and molecular heterogeneity and genetic polymorphisms associated with susceptibility. Every leukemia presents causal factors associated with the development of the disease. Particularly, when three factors are present, they result in the development of acute leukemia. These phenomena are susceptibility, environmental exposure and a period that, for this model, has been called the period of vulnerability. This framework shows how the concepts of molecular epidemiology have established a reference from which it is more feasible to identify the environmental factors associated with the development of leukemia in children. Subsequently, the arguments show that only susceptible children are likely to develop leukemia once exposed to an environmental factor. For additional exposure, if the child is not susceptible to leukemia, the disease does not develop. In addition, this exposure should occur during a time window when hematopoietic cells and their environment are more vulnerable to such interaction, causing the development of leukemia. This model seeks to predict the time when the leukemia develops and attempts to give a context in which the causality of childhood leukemia should be studied. This information can influence and reduce the risk of a child developing leukemia.

The effect of environmental chemicals on the tumor microenvironment

Potentially carcinogenic compounds may cause cancer through direct DNA damage or through indirect cellular or physiological effects. To study possible carcinogens, the fields of endocrinology, genetics, epigenetics, medicine, environmental health, toxicology, pharmacology and oncology must be considered. Disruptive chemicals may also contribute to multiple stages of tumor development through effects on the tumor microenvironment. In turn, the tumor microenvironment consists of a complex interaction among blood vessels that feed the tumor, the extracellular matrix that provides structural and biochemical support, signaling molecules that send messages and soluble factors such as cytokines. The tumor microenvironment also consists of many host cellular effectors including multipotent stromal cells/mesenchymal stem cells, fibroblasts, endothelial cell precursors, antigen-presenting cells, lymphocytes and innate immune cells. Carcinogens can influence the tumor microenvironment through effects on epithelial cells, the most common origin of cancer, as well as on stromal cells, extracellular matrix components and immune cells. Here, we review how environmental exposures can perturb the tumor microenvironment. We suggest a role for disrupting chemicals such as nickel chloride, Bisphenol A, butyltins, methylmercury and paraquat as well as more traditional carcinogens, such as radiation, and pharmaceuticals, such as diabetes medications, in the disruption of the tumor microenvironment. Further studies interrogating the role of chemicals and their mixtures in dose-dependent effects on the tumor microenvironment could have important general mechanistic implications for the etiology and prevention of tumorigenesis.

Impacts of soil and water pollution on food safety and health risks in China

Environmental pollution and food safety are two of the most important issues of our time. Soil and water pollution, in particular, have historically impacted on food safety which represents an important threat to human health. Nowhere has that situation been more complex and challenging than in China, where a combination of pollution and an increasing food safety risk have affected a large part of the population. Water scarcity, pesticide over-application, and chemical pollutants are considered to be the most important factors impacting on food safety in China. Inadequate quantity and quality of surface water resources in China have led to the long-term use of waste-water irrigation to fulfill the water requirements for agricultural production. In some regions this has caused serious agricultural land and food pollution, especially for heavy metals. It is important, therefore, that issues threatening food safety such as combined pesticide residues and heavy metal pollution are addressed to reduce risks to human health. The increasing negative effects on food safety from water and soil pollution have put more people at risk of carcinogenic diseases, potentially contributing to 'cancer villages' which appear to correlate strongly with the main food producing areas. Currently in China, food safety policies are not integrated with soil and water pollution management policies. Here, a comprehensive map of both soil and water pollution threats to food safety in China is presented and integrated policies addressing soil and water pollution for achieving food safety are suggested to provide a holistic approach.

siRNA-mediated downregulation of TC21 sensitizes esophageal cancer cells to cisplatin

AIM: To determine the functional significance of TC21 in esophageal squamous cell carcinoma (ESCC).

METHODS: TC21 siRNA transfection was carried out using Hyperfectamine to knock down TC21, and transcripts were analyzed by reverse transcription-polymerase chain reaction and protein by Western blotting. We demonstrated the effect of TC21 downregulation of cell signaling in esophageal cancer cells by assessing the phosphorylation status of its downstream targets, phosphoinositide 3-kinase (PI3K), phosphatase and tensin homolog (PTEN), protein kinase B (pAkt), nuclear factor-κB (NF-κB) and cyclinD1 using specific antibodies. Cell survival analysis after cisplatin treatment was carried out by cell viability assay and cell cycle analysis using flow cytometry.

RESULTS: TC21 knockdown in human ESCC cell line TE13 cells, showed only a marginal increase (14.2%) in cell death compared with control cells. The expressions of the signaling proteins PI3K and pAkt, transcription factor NF-κB, and cell cycle protein cyclin D1 were markedly decreased in response to TC21 downregulation, whereas the level of pPTEN, an antagonist of PI3K, was increased. In addition, we evaluated the potential of TC21 as a putative target for sensitizing ESCC cells to the chemotherapeutic agent cisplatin. Increased cell death (38.4%) was observed in cells treated with cisplatin after TC21 knockdown compared with cells which were treated with cisplatin alone (20% cell death).

CONCLUSION: Results suggest that TC21 mediates its effects via the PI3K-Akt pathway, NF-κB and cyclin D1, and enhances chemoresistance in esophageal cancer cells.

The effects of radioactive pollution on the dynamics of infectious diseases in wildlife

The interactions between infectious diseases and chemical pollution are well known and recognised as important factors in regulating the way wild animals respond to contaminant exposure. However, the impact of ionising radiation and radionuclides has often been overlooked when assessing host-pathogen interactions in polluted habitats, despite often occurring together with chemical contamination. Nevertheless, a comprehensive body of literature exists from laboratory and field studies on host-pathogen relationships under radiation exposure, and with a renewed interest in radioecology developing; an evaluation of infectious disease dynamics under these conditions would be timely. The present study assesses the impact of external ionising radiation and radionuclides on animal hosts and pathogens (viruses, bacteria, protozoans, helminths, arthropods) in laboratory studies and collates the data from field studies, including the large number of investigations undertaken after the Chernobyl accident. It is apparent that radiation exposure has substantial effects on host-pathogen relationships. Although damage to the host immune system is a major factor other variables, such as damage to host tissue barriers and inhibition of pathogen viability are also important in affecting the prevalence and intensity of parasitic diseases. Field studies indicate that the occurrence of host-pathogen associations in radioactively contaminated sites is complex with a variety of biotic and abiotic factors influencing both pathogen and host(s), resulting in changes to the dynamics of infectious diseases.

CYP2E1 PstI/RsaI polymorphism and colorectal cancer risk: A meta-analysis

AIM: To clarify the association between CYP2E1 PstI/RsaI polymorphism and susceptibility to colorectal cancer.

METHODS: A meta-analysis based on 10 eligible case-control studies involving 4979 cases and 6012 controls was carried out to summarize the data on the association between CYP2E1 RsaI/PstI polymorphism and colorectal cancer risk.

RESULTS: In comparison of the homozygote c2c2 and c2 carriers (c1c2 + c2c2) and the homozygous wild-type genotype (c1c1), no association was found between CYP2E1 RsaI/PstI polymorphism and colorectal cancer risk [odds ratio (OR) = 1.24 (95% CI: 0.93-1.66) for c2c2; OR = 1.02 (95% CI: 0.88-1.19) for c2 carriers]. In stratified analysis, Caucasians with c2c2 homozygote appeared to have an increased risk of colorectal cancer (OR = 2.67, 95% CI: 1.03-6.89, P = 0.043), no significant associations were found in other groups.

CONCLUSION: c2c2 homozygote of CYP2E1 PstI/RsaI polymorphism may be associated with the increased risk of colorectal cancer in Caucasians, which needs further investigations.

Anticancer and cancer chemopreventive potential of grape seed extract and other grape-based products

With emerging trends in the incidence of cancer of various organ sites, additional approaches are needed to control human malignancies. Intervention or prevention of cancer by dietary constituents, a strategy defined as chemoprevention, holds great promise in our conquest to control cancer, because it can be implemented on a broader population base with less economic burden. Consistent with this, several epidemiological studies have shown that populations that consume diets rich in fruits and vegetables have an overall lower cancer incidence. Based on these encouraging observations, research efforts from across the globe have focused on identifying, characterizing, and providing scientific basis to the efficacy of various phytonutrients in an effort to develop effective strategy to control various human malignancies. Cancer induction, growth, and progression are multi-step events and numerous studies have demonstrated that various dietary agents interfere with these stages of cancer, thus blocking malignancy. Fruits and vegetables represent untapped reservoir of various nutritive and nonnutritive phytochemicals with potential cancer chemopreventive activity. Grapes and grape-based products are one such class of dietary products that have shown cancer chemopreventive potential and are also known to improve overall human health. This review focuses on recent advancements in cancer chemopreventive and anticancer efficacy of grape seed extract and other grape-based products. Overall, completed studies from various scientific groups conclude that both grapes and grape-based products are excellent sources of various anticancer agents and their regular consumption should thus be beneficial to the general population.

How to minimize formation and growth of tumours: potential benefits of decapod crustaceans for cancer research

Tumours have only rarely been observed in the decapod crustaceans, a large animal group of more than 10,000 species that includes the commercially important and well investigated shrimp, lobsters, crayfish and crabs. Analysis of the literature and information from cancer and diseases data bases revealed a total of 15 incidences, some of them being questionable. Even in the long-lived species, which can reach life spans of almost 100 years, neoplasias are virtually unknown. The data published so far suggest that the strikingly different frequencies of carcinogenesis between decapods and other well investigated animal groups like mammals, fish, insects and molluscs is based on differences of the metabolic pathways for carcinogens, the immune systems, and the regulation of stem cells. Therefore, representatives of the Decapoda may serve as useful models to study how organisms can successfully prevent or control spontaneously and environmentally induced cell proliferation. A particularly promising candidate for in-depth investigation of these topics is the marbled crayfish, a rather new clonal lineage that is presently being introduced as a laboratory model in development and epigenetics.

Carcinogenesis and aging 20 years after: escaping horizon

Carcinogenesis is a multistage process: neoplastic transformation implies the engagement of a cell through sequential stages, and different agents may affect the transition between continuous stages. Multistage carcinogenesis is accompanied by disturbances in tissue homeostasis and perturbations in nervous, hormonal, and metabolic factors which may affect antitumor resistance. The development of these changes depends on the susceptibility of various systems to a carcinogen and on the dose of the carcinogen. Changes in the microenvironment may condition key carcinogenic events and determine the duration of each carcinogenic stage, and sometimes they may even reverse the process of carcinogenesis. These microenvironmental changes influence the proliferation rate of transformed cells, the total duration of carcinogenesis and, consequently, the latent period of tumor development. Aging may increase or decrease the susceptibility of various tissues to initiation of carcinogenesis and usually facilitates promotion and progression of carcinogenesis. Aging may predispose to cancer by two mechanisms: tissue accumulation of cells in late stages of carcinogenesis and alterations in internal homeostasis, in particular, alterations in immune and endocrine system. Aging is associated with number of events at molecular, cellular and physiological levels that influence carcinogenesis and subsequent cancer growth.

The relationship between aging and carcinogenesis: a critical appraisal

The incidence of cancer increases with age in humans and in laboratory animals alike. There are different patterns of age-related distribution of tumors in different organs and tissues. Aging may increase or decrease the susceptibility of various tissues to initiation of carcinogenesis and usually facilitates promotion and progression of carcinogenesis. Aging may predispose to cancer by several mechanisms: (1) tissue accumulation of cells in late stages of carcinogenesis; (2) alterations in homeostasis, in particular, alterations in immune and endocrine system and (3) telomere instability linking aging and increased cancer risk. Increased susceptibility to the effects of tumor promoters is found both in aged animals and aged humans, as predicted by the multistage model of carcinogenesis. Available evidence supporting the relevance of replicative senescence of human cells and telomere biology to human cancer seems quite strong, however, the evidence linking cellular senescence to human aging is controversial and required additional studies. Data on the acceleration of aging by carcinogenic agents as well as on increased cancer risk in patients with premature aging are critically discussed. In genetically modified mouse models (transgenic, knockout or mutant) characterized by the aging delay, the incidence of tumors usually similar to those in controls, whereas the latent period of tumor development is increased. Practically all models of accelerated of aging in genetically modified animals show the increase in the incidence and the reduction in the latency of tumors. Strategies for cancer prevention must include not only measures to minimize exposure to exogenous carcinogenic agents, but also measures to normalize the age-related alterations in internal milieu. Life-span prolonging drugs (geroprotectors) may either postpone population aging and increase of tumor latency or decrease the mortality in long-living individuals in populations and inhibit carcinogenesis. At least some geroprotectors may increase the survival of a short-living individuals in populations but increase the incidence of malignancy.

Phase I safety, pharmacokinetic, and pharmacodynamic trial of ZD1839, a selective oral epidermal growth factor receptor tyrosine kinase inhibitor, in patients with five selected solid tumor types

PURPOSE

To establish the safety and tolerability of ZD1839 (Iressa), a selective epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, and to explore its pharmacokinetic and pharmacodynamic effects in patients with selected solid tumor types.

PATIENTS AND METHODS

This was a phase I dose-escalating trial of oral ZD1839 150 mg/d to a maximum of 1,000 mg/d given once daily for at least 28 days. Patients with either advanced non-small-cell lung, ovarian, head and neck, prostate, or colorectal cancer were recruited.

RESULTS

Eighty-eight patients received ZD1839 (150 to 1,000 mg/d). At 1,000 mg/d, five of 12 patients experienced dose-limiting toxicity (grade 3 diarrhea [four patients] and grade 3 somnolence [one patient]). The most frequent drug-related adverse events (AEs) were acne-like rash (64%) and diarrhea (47%), which were generally mild (grade 1/2) and reversible on cessation of treatment. No change in ZD1839 safety profile was observed with prolonged administration. Pharmacokinetic analysis showed steady-state exposure to ZD1839 in 98% of patients by day 7. Nineteen patients had stable disease and received ZD1839 for >or= 3 months; seven of these patients remained on study drug for >or= 6 months. Serial skin biopsies taken before treatment and at approximately day 28 revealed changes indicative of inhibition of the EGFR signaling pathway.

CONCLUSION

ZD1839 was generally well tolerated, with manageable and reversible AEs at doses up to 600 mg/d and dose-limiting toxicity observed at 1,000 mg/d. ZD1839 treatment resulted in clinically meaningful disease stabilization across a range of tumor types and doses. Pharmacodynamic changes in skin confirmed inhibition of EGFR signaling, which was predicted from the mode of action of ZD1839.

Hepatitis B immunization and hepatocellular carcinoma: The Gambia Hepatitis Intervention Study

The Gambia Hepatitis Intervention Study (GHIS) was initiated by the International Agency for Research on Cancer (IARC) in 1986. It consisted of a randomized trial in the Gambian population, aiming to evaluate the protection provided by HBV vaccination administered during the first year of life against primary infection, the development of chronic carriage, and primary liver cancer. The results, reported at 9 years from the introduction of the vaccine as conferring a high degree of protection (83% against primary infection and 95% against chronic carriage), are briefly discussed. It is expected that HBV vaccination will result in a reduction of mortality from hepatocellular carcinoma, the most frequent cancer in males in sub-Sahara Africa.

Primary and secondary prevention in the reduction of cancer morbidity and mortality

Overall, cancer is a highly preventable disease. Indeed, modifiable external factors, discovered by epidemiological studies during the last 50 years, account for a majority of all cancer deaths. In this review, we discuss briefly these factors and their contribution to the current burden of cancer with an emphasis on the developed countries. Needless to say, tobacco smoking remains the largest contributor to the cancer landscape, whilst the contribution of poor diet and obesity may be equally important, but much more difficult to quantify. Our main goal was to assess what prevention of cancer has accomplished and might accomplish in the next two decades. Based on (necessarily crude) estimates, age-adjusted mortality rates from cancer in year 2000 had been reduced by approximately 13% due to primary prevention and an additional 6% due to the combined effect of early diagnosis and screening (secondary prevention). According to a realistic goal for the year 2020, a further 29% reduction might be achieved by primary, and 4% by secondary prevention. The main contribution to such accomplishments would be a reduction in tobacco smoking, improvements in diet--including reduced alcohol intake--and arrest of the obesity epidemic, in part through increased physical exercise. Rather than being granted, these goals require great effort and major commitment from all those who share responsibility for public health.