Environmental exposure to carcinogens in northwestern Cameroon.

BACKGROUND: In developing countries, 6% of deaths are due to cancer but cancer prevention is not practiced. Humans can prevent themselves from a number of workplace and environmental carcinogens. OBJECTIVES: To assess exposure to carcinogens, risky behaviours and associated preventive methods. METHODS: A structured questionnaire was used to collect information on carcinogen exposure in the workplace and environment through trained field staff from volunteers after gaining informed consent. Data was analysed using SPSS. RESULTS: Participants were exposed to recognized carcinogens and environmental hazards. Thirty-five (83.3%) [95% CI: 72.0- 94.6] participants knew the carcinogen names they were exposed to. Common hygienic practices such as taking a bath and washing work dresses at the workplace, use of detergents to wash hands, and no smoking or eating at the workplace were poor. Twenty-nine (69.0%) [95% CI: 47.0 - 75.0] participants could smell the carcinogenic chemicals they use. Thirty (71.4%) [95% CI: 65.0 - 77.0] participants had been instructed in the use of protective equipment against carcinogens. Participants used preventive devices like hand gloves, laboratory coats, boots, face masks, goggles, ear plugs and respirators. CONCLUSIONS: Exposure to carcinogens is common necessitating case-control and cohort studies in this locality on cancer prevalence and incidence.

Cervical human papillomavirus and HIV infection in women of child-bearing age in Abidjan, Côte d'Ivoire, 2010.

BACKGROUND: We sought to document the association of Human immunodeficiency Virus (HIV) infection and immunodeficiency with oncogenic Human Papillomavirus (HPV) infection in women with no cervical neoplastic lesions identified through a cervical cancer screening programme in Côte d'Ivoire. METHODS: A consecutive sample of women stratified on their HIV status and attending the national blood donor clinic or the closest HIV clinic was recruited during a cervical cancer screening programme based on the visual inspection. Diagnosis of HPV infection and genotype identification were based on the Linear Array; HPV test. RESULTS: A total of 445 (254 HIV-positive and 191 HIV-negative) women were included. The prevalence of oncogenic HPV infection was 53.9% (95% confidence interval (CI) 47.9-59.9) in HIV-positive women and 33.7% (95% CI 27.1-40.3) in HIV-negative women (odds ratio (OR)=2.3 (95% CI 1.5-3.3)). In multivariate analysis, HIV-positive women with a CD4 count <200 cells mm(3) or between 200 and 499 cells mm(3) were more likely to harbour an oncogenic HPV compared with women with a CD4 count ≥500 cells mm(3) with OR of 2.8 (95% CI 1.1-8.1) and 1.7 (95% CI 1.0-2.9), respectively. CONCLUSION: A high prevalence of oncogenic HPV was found in women with no cervical neoplastic lesions, especially in HIV-positive women. Despite antiretroviral use, immunodeficiency was a main determinant of the presence of oncogenic HPV.

High expression of gabarapl1 is associated with a better outcome for patients with lymph node-positive breast cancer.

BACKGROUND: This study evaluates the relation of the early oestrogen-regulated gene gabarapl1 to cellular growth and its prognostic significance in breast adenocarcinoma. METHODS: First, the relation between GABARAPL1 expression and MCF-7 growth rate was analysed. Thereafter, by performing macroarray and reverse transcriptase quantitative-polymerase chain reaction (RT-qPCR) experiments, gabarapl1 expression was quantified in several histological breast tumour types and in a retrospective cohort of 265 breast cancers. RESULTS: GABARAPL1 overexpression inhibited MCF-7 growth rate and gabarapl1 expression was downregulated in breast tumours. Gabarapl1 mRNA levels were found to be significantly lower in tumours presenting a high histological grade, with a lymph node-positive (pN+) and oestrogen and/or progesterone receptor-negative status. In univariate analysis, high gabarapl1 levels were associated with a lower risk of metastasis in all patients (hazard ratio (HR) 4.96), as well as in pN+ patients (HR 14.96). In multivariate analysis, gabarapl1 expression remained significant in all patients (HR 3.63), as well as in pN+ patients (HR 5.65). In univariate or multivariate analysis, gabarapl1 expression did not disclose any difference in metastasis risk in lymph node-negative patients. CONCLUSIONS: Our data show for the first time that the level of gabarapl1 mRNA expression in breast tumours is a good indicator of the risk of recurrence, specifically in pN+ patients.

Evaluation of DNA damage by the alkaline comet assay of the olfactory and respiratory epithelia of dogs from the city of São Paulo, Brazil.

Animals kept as pets may be considered sentinels for environmental factors to which humans could be exposed. Olfactory and respiratory epithelia are directly subjected to airborne factors, which could cause DNA lesions, and the alkaline comet assay is considered a reliable tool for the assessment of DNA damage. The objective of this work is to evaluate the extent of DNA damage by the comet assay of the olfactory and respiratory epithelia of dogs from different regions of the city of São Paulo, Brazil. Thirty-three clinically healthy dogs, aged 5 years or more, were used in the study, with 7 from the North region of São Paulo, 7 from the South region, 3 dogs from the East region, and 16 dogs from the West city region. Three dogs younger than 6 months were used as controls. DNA damage was analyzed by the alkaline comet assay. We observed no difference in histopathological analysis of olfactory and respiratory epithelia between dogs from different regions of São Paulo. Dogs older than 5 years presented significantly higher comet length in both olfactory and respiratory epithelia, when compared with controls, indicating DNA damage. When separated by regions, olfactory and respiratory epithelia presented similar DNA damage in dogs from different regions of São Paulo, corroborating with similar levels of particulate matter index (PM10) in all regions of the city. In this study, we report for the first time that the comet assay can be used to quantify the extent of DNA damage in dog olfactory and respiratory epithelia, and that comet length (DNA damage) increases with age, probably due to environmental factors. Air pollution, as measured by PM10, can be responsible for this DNA damage.

Tobacco use and its determinants in HIV-infected patients on antiretroviral therapy in West African countries.

BACKGROUND: Tobacco smoking is common in human immunodeficiency virus (HIV) infected patients from industrialised countries. In West Africa, few data concerning tobacco consumption exist. METHODS: A cross-sectional survey of the International Epidemiological Database to Evaluate AIDS (IeDEA) network in West Africa was conducted. Health workers administered a questionnaire assessing tobacco and cannabis consumption among patients receiving antiretroviral treatment. Regular smokers were defined as current smokers who smoked >1 cigarette per day for >or=1 year. RESULTS: Overall, 2920 patients were enrolled in three countries. The prevalence of ever smokers and regular smokers were respectively 46.2% (95%CI 42.8-49.5) and 15.6% (95%CI 13.2-18.0) in men and 3.7% (95%CI 2.9-4.5) and 0.6% (95%CI 0.3-0.9) in women. Regular smoking was associated with being from Côte d'Ivoire or Mali compared to Benin (OR 4.6, 95%CI 2.9-7.3 and 7.7, 95%CI 4.4-13.6), severely impaired immunological status at highly active antiretroviral treatment initiation (OR 1.5, 95%CI 1.1-2.2) and history of tuberculosis (TB; OR 1.8, 95%CI 1.1-3.0). CONCLUSION: There are marked differences in smoking prevalence among these West African countries. This survey approach also provides proof of the association between cigarette smoking and TB in HIV-infected patients, a major public health issue in this part of the world.

Flexible regression models for dynamic prediction of survival in elderly in presence of cancer or other chronic diseases.

We consider degradation and failure time models with multiple failure modes adapted for the statistical analysis of survival in the elderly in presence of chronic diseases such as cancer, but also other conditions like dementia, Alzheimer, diabetes, etc... These models can be applied in gerontology, general medicine, biology and demography for the analysis of longevity and survival of highly complex biological systems as any human is.

Alternative forms of tobacco use.

BACKGROUND: A review of the available scientific literature concerning forms of tobacco use other than regular cigarettes, cigars and pipes, the nature of such products, prevalence data and trends, health effects, regulatory issues and preventive measures. RESULTS: Narghile (water pipe), bidis, kreteks and other forms of oral tobacco are traditionally used in many low-income countries, and some of these are currently spreading to the Western countries. They are all linked to negative effects similar to, and often greater than, those associated with common cigarette smoking. Various potentially reduced exposure products (PREPs), including snus, targeted at smokers aware of the health risks of regular cigarettes, have recently been developed by the tobacco industry. Their pathogenic potential varies widely and is not fully known; it is in any case greater than that of pure nicotine forms (such as medicinal nicotine). Their use as cigarette substitutes should not be considered even by inveterate smokers who are unable or unwilling to quit nicotine before further independent evaluation and control. CONCLUSIONS: There is no such thing as a safe tobacco product. Like cigarettes, alternative forms of tobacco use need regulatory measures that are adapted to local situations and supplemented by preventive measures within the World Health Organization's Framework Convention for Tobacco Control.

The multitude and diversity of environmental carcinogens.

We have recently proposed that lifestyle-related factors, screening and aging cannot fully account for the present overall growing incidence of cancer. In order to propose the concept that in addition to lifestyle related factors, exogenous environmental factors may play a more important role in carcinogenesis than it is expected, and may therefore account for the growing incidence of cancer, we overview herein environmental factors, rated as certainly or potentially carcinogenic by the International Agency for Research on Cancer (IARC). We thus analyze the carcinogenic effect of microorganisms (including viruses), radiations (including radioactivity, UV and pulsed electromagnetic fields) and xenochemicals. Chemicals related to environmental pollution appear to be of critical importance, since they can induce occupational cancers as well as other cancers. Of major concerns are: outdoor air pollution by carbon particles associated with polycyclic aromatic hydrocarbons; indoor air pollution by environmental tobacco smoke, formaldehyde and volatile organic compounds such as benzene and 1,3 butadiene, which may particularly affect children, and food pollution by food additives and by carcinogenic contaminants such as nitrates, pesticides, dioxins and other organochlorines. In addition, carcinogenic metals and metalloids, pharmaceutical medicines and cosmetics may be involved. Although the risk fraction attributable to environmental factors is still unknown, this long list of carcinogenic and especially mutagenic factors supports our working hypothesis according to which numerous cancers may in fact be caused by the recent modification of our environment.

The growing incidence of cancer: role of lifestyle and screening detection (Review).

The increasing incidence of a variety of cancers after the Second World War confronts scientists with the question of their origin. In Western countries, expansion and ageing of the population, as well as progress in cancer detection using new diagnostic and screening tests cannot fully account for the observed growing incidence of cancer. Our hypothesis is that environmental factors play a more important role in cancer genesis than it is usually agreed: i) over the last 2-3 decades, alcohol consumption and tobacco smoking in men have significantly decreased; ii) obesity is increasing in many countries, but the growing incidence of cancer also concerns cancers not related to obesity nor to other lifestyle-related factors; iii) there is evidence that the environment has changed over the same time scale as the recent rise in cancer incidence, and that this change included the accumulation of many new carcinogenic factors in the environment; iv) genetic susceptibility to cancer due to genetic polymorphism cannot have changed over one generation and actually favours the role of exogenous factors through gene-environment interactions; v) age is not the unique factor to be considered since the rising incidence of cancers is seen across all age categories, including children; vi) the fetus is specifically vulnerable to exogenous factors. A fetal exposure during a critical window period may explain why current epidemiological studies may be negative in adults. We therefore propose that the involuntary exposure to many carcinogens in the environment contributes to the rising trend in cancer incidence.

An ovarian dysgerminoma in Down syndrome. Hypothesis about the association.

An 11-year-old girl with Down syndrome (DS) was operated for a stage I right ovary dysgerminoma. She is in good health 33 years later. Some data in the literature suggest that ovarian cancers could be slightly overrepresented in DS. Despite the rarity of ovarian dysgerminoma, our case is the fifth reported in DS. This case is the second one associated with a family history suggesting the possibility of a familial predisposition to cancer. A hypothesis explaining the development of dysgerminoma in DS is proposed.

[Smoking (active or passive) in relation to fertility, medically assisted procreation and pregnancy]. / Tabagisme (actif ou passif) en relation avec la fertilité, la procréation médicalement assistée et la grossesse.

Maternal and paternal smoking are associated with numerous problems of reproduction and pregnancy. Among men, active smoking reduces the quality and mobility of the spermatozoa which could result in loss of fertility. It also increases the risk of impotence. Moreover, active smoking of the father is responsible for passive smoking for the mother and her baby. Among women, active smoking has a negative impact on fertility and in case of treatments against infertility, the chances of success are reduced. It leads to delayed conception and increases the risk of ectopic pregnancies and placental complications. It reduces the risk of pre-eclampsia but it also worsens its consequences. Passive smoking has not been associated with certainty with any clear impact on fertility among men and women. By contrast, active and passive smoking can lead to intra-uterine growth retardation and a lower birth weight.

Tobacco smoking and cancer: a brief review of recent epidemiological evidence.

This report summarises the epidemiological evidence on the association between tobacco smoking and cancer, which was reviewed by an international group of scientists convened by IARC. Studies published since the 1986 IARC Monograph on "Tobacco smoking" provide sufficient evidence to establish a causal association between cigarette smoking and cancer of the nasal cavities and paranasal sinuses, nasopharynx, stomach, liver, kidney (renal cell carcinoma) and uterine cervix, and for adenocarcinoma of the oesophagus and myeloid leukaemia. These sites add to the previously established list of cancers causally associated with cigarette smoking, namely cancer of the lung, oral cavity, pharynx, larynx, oesophagus, pancreas, urinary bladder and renal pelvis. Other forms of tobacco smoking, such as cigars, pipes and bidis, also increase risk for cancer, including cancer of the lung and parts of the upper aerodigestive tract. A meta-analysis of over 50 studies on involuntary smoking among never smokers showed a consistent and statistically significant association between exposure to environmental tobacco smoke and lung cancer risk. Smoking is currently responsible for a third of all cancer deaths in many Western countries. It has been estimated that every other smoker will be killed by tobacco.

Survival after proton-beam irradiation of uveal melanomas.

PURPOSE: To evaluate the independent prognostic factors for survival, metastasis, local recurrence, and enucleation in patients who had undergone proton-beam therapy for posterior uveal melanomas. DESIGN: Interventional case series. METHODS: In this retrospective study, 224 consecutive incident cases were treated at the Biomedical Cyclotron Centre (Nice, France) from June 1991 to December 1997. Overall, metastasis-free, local recurrence-free, and enucleation-free survival rates were calculated according to the Kaplan-Meier method using the log-rank test. The multivariate prognostic analysis was performed using the Cox proportional hazards model. RESULTS: The 5-year overall survival rate was 78.1% (SE: 3.7%). A largest basal tumor diameter (LTD) below 10 mm and female sex were independently associated with a better prognosis. The 5-year metastasis-free survival rate was 75.6% (SE: 3.6%). Only an LTD above 10 mm and ciliary body involvement were independently associated with metastasis. Ten patients (4.5%) had a local recurrence, which was correlated with the risk of metastasis (P =.045). The 5-year enucleation-free survival rate was 69.6% (SE: 4.0%). Once again, an LTD below 10 mm and female sex were predictive of a better prognosis. CONCLUSION: Our results with proton-beam therapy correspond to those reported in the literature. This treatment strategy is safe and yields predictably good results. In addition to the two independent prognostic factors for survival and metastasis, namely LTD and ciliary body involvement, sex also had a significant impact in our case series, but the clinical relevance of this finding is unknown.

[Evaluation of adherence to the regulations for declaration of notification of transfusion reactions with fever and chills. A study of the Association Inter-Régionale du Sud-Est d'Hémovigilance (AIRSEH)]. / Evaluation de la conformité à la réglementation des déclarations d'incidents transfusionnels pour frissons-hyperthermie dans des établissements de santé du sud-est de la France (groupe AIRSEH).

Febrile non-hemolytic transfusion reactions (FNHTR) are the most frequently reported acute adverse effects of blood products, and should be notified within 48 h according to the hemovigilance regulation. In order to study the conformity of these notifications and to search for factors associated with non-conformity, we retrospectively studied all FNHTR notified by voluntary centers of the AIRSEH group from 1st September 1994 to 31st December 1999. Seven hundred and sixty-one FNHTR were registered by 10 centers, most of them were benign (grade 1); 67.8% were non-conform. The non-conformity was associated with the number of biological investigations performed (median number, respectively, 4.24 and 2.94--P = 0.038--in non-conform and conform notifications--P = 0.038) in univariate analysis. Using a logistic regression model, center and severity were the only two factors significantly associated with non-conformity. Different center practices, and in particular the interface between the hospital and the blood bank, may be responsible for the effect center. Moreover, the non-conformity concerns first of all benign FNHTR. A stronger separation between alert and epidemiological surveillance is proposed in order to improve the notifications' conformity.

The epidemiology of neonatal tumours. Report of an international working group.

Neonatal tumours occur every 12,500-27,500 live births and comprise 2% of childhood malignancies, but there is little clarity as to their real prevalence, sites of origin and pathological nature as reported series vary. As an entity, neonatal tumours provide a unique window of opportunity to study tumours in which minimal environmental interference has occurred. The majority of tumours present with a mass at birth (e.g., teratomas, neuroblastomas, mesoblastic nephroma, fibromatosis), which are not infrequently identified on antenatal ultrasound. Histologically, teratoma and neuroblastoma remain the two main tumour types encountered with soft tissue sarcoma, renal tumours, CNS tumours and leukaemia being the next most common tumour types identified. Malignant tumours are uncommon in the neonatal period per se and benign tumours may have malignant potential. A particular problem exists in clinical classification, as histological features of malignancy do not always correlate with clinical behaviour. Benign tumours may also be life threatening because of their size and location. Other tumours may demonstrate local invasiveness, but no metastatic potential, and tumours that are clearly malignant may demonstrate unpredictable or uncertain behaviour. Screening programmes have brought more tumours to light, but do not appear to affect the overall prognosis. They may provide clues to the stage at which tumours develop in foetu. The aetiology of cancer in children is multifactorial and includes both genetic and environmental factors. The association between congenital abnormalities and tumours is well established (15% of neonatal tumours). Genetic defects are highly likely in neonatal tumours and include those with a high risk of malignancy (e.g., retinoblastoma), but also genetically determined syndromes with an increased risk of malignancy and complex genetic rearrangements. Tumours are mostly genetically related at a cellular level and factors influencing cellular maturation or apoptosis within the developing foetus may continue to operate in the neonatal period. Cytogenetics of neonatal neoplasms appear to differ from neoplasms in older children, thus possibly explaining some of the observed differences in clinical behaviour. Certain constitutional chromosome anomalies, however, specifically favour tumours occurring in the foetal and neonatal period. In support of this hypothesis, certain cytogenetic anomalies appear to be specific to neonates, and a number of examples are explored. Other environmental associations include ionizing radiation, drugs taken during pregnancy, infections, tumours in the mother and environmental exposure.

Estimating the distribution of lag in the effect of short-term exposures and interventions: adaptation of a non-parametric regression spline model.

Information on the distribution of lag duration between exposure or intervention and the subsequent changes in risk can help in assessing the impact of exposure, predicting cost-effectiveness of intervention, and understanding the underlying biological mechanisms. Previous approaches focused more on optimizing the strength of the exposure-disease association than on directly estimating lag duration. We propose an alternative approach applicable to the analysis of the lagged effects of binary exposure variables. The density function of the distribution of lags is estimated based on flexible modelling of changes in hazard ratio of exposed versus unexposed subjects. The methodology is evaluated in a simulation study and is applied to the Framingham data to investigate the lagged effect of smoking cessation on coronary heart disease risk.

Trends in tobacco smoking among adolescents in Lyon, France.

To provide information that may promote more effective cancer prevention, we identified factors associated with regular smoking among adolescents in Lyon, France. School grades where these factors began to influence regular smoking were also identified. Seven consecutive cross-sectional anonymous surveys were conducted in three public schools, beginning in grade 6ème (average age 11.5 years) in 1993 and ending in grade Terminale (average age 17.4 years) in 1999. All classes in each respective grade were surveyed, with 3650 completed questionnaires for all years combined. Prevalence of current regular smoking is presented according to school grade for 17 variables identified as significantly related to regular smoking in a multivariate logistic regression analysis. Important factors associated with regular smoking were identified as early as grade 6ème and included not viewing the taking care of one's health as important, not eating breakfast regularly, associating with groups where smoking occurs, having a best friend who smokes, and having a brother and/or sister who smokes. Not regularly reading was first associated with an increased risk of regular smoking in grade 5ème. Not living with both parents, alcohol drinking, episodes of drunkenness, illicit drug use, and sexual relationships were positively associated with regular smoking in the middle and later grades, when these questions were first asked. Not playing sports and not playing with computers were initially associated with an increased risk of regular smoking in grade 3ème.

Cancer: the role of extracellular disease.

Invasive carcinoma originates from the epithelial cells lining the lumen of an organ. It is often preceded by metaplasia, dysplasia or carcinoma in situ. The purpose of this review is to suggest that this disease of the epithelium may be, in part, the result of underlying tissue-based disorganization. Human cancer is frequently associated with pre-existing tissue disease. For example, hepatocellular carcinoma usually occurs in patients with a macronodular cirrhotic liver. Most lung cancers arise among patients with chronic lung disease (bronchitis, emphysema, and chronic infection). Mechanical forces appear to play a major role in regulating normal and cancer cell growth. The loss of cell polarity by neoplastic cells, coupled to an otherwise normal growth rate is enough to explain the cancer star-shaped pattern. By changing the plane of cell division, tumor cells may escape physical constraints from surrounding cells and divide. Loss of cell polarity and the resulting cell proliferation appears to be a consequence of either tissue-based disorganization (chronic inflammation, fibrosis) or of direct carcinogenic insult. The multiple mutations frequently described in cancer may be, in part, secondary to physical stress and not primary events. Several animal and clinical trials have shown that tissue disruption (i.e. radiation-induced fibrosis or liver cirrhosis) can be successfully treated. It is possible that treatment targeted at tissue disruption would delay or reduce cancer incidence regardless of the precise biological mechanism of carcinogenesis.

[Epidemiology of uterine cancers]. / Epidémiologie des cancers utérins.

Uterine cancers comprise 2 distinct pathological entities: cancer of the cervix and cancer of the corpus. They differ both in descriptive and etiologic epidemiology. Cervical cancer is more frequent in the developing world, is decreasing in terms of incidence and even more mortality in many countries and has essentially a viral etiology, being linked to human papilloma viruses. Cancer of the uterine corpus is more frequent in the developed world, is rather stable in terms of incidence and mostly has a hormonal etiology.