Risk of cancer and exposure to gasoline vapors

Occupational Benzene Exposure and Risk of Male Genital Cancers: A Systematic Review and Meta-Analysis

BACKGROUND

Benzene is an established Group 1 carcinogen due to its leukemogenic properties. Recent studies suggest that occupational benzene exposure may be associated with solid cancers. However, little is known about its association with male genital cancers. We aimed to summarize the scientific evidence on occupational benzene exposure and the risk of male genital cancers.

METHODS

We searched for relevant articles in three electronic databases. Methodological quality and the certainty of evidence were evaluated using a modified version of the Newcastle-Ottawa Scale (NOS) and Grading of Recommendations Assessment, Development and Evaluation (GRADE) assessment tool. We performed pooled and stratified meta-analyses, as well as meta-regressions to explore potential sources of heterogeneity.

RESULTS

Thirty-one publications were included. Pooled results of incidence and mortality for prostate and testis cancer did not indicate a significant association with occupational benzene exposure. A borderline association was found for the incidence of prostate cancer (standardized incidence ratio (SIR): 1.07, 95% CI 0.97-1.19). Subgroup analyses stratified by study design and study quality revealed significant heterogeneity, with case-control (relative risk (RR): 1.19, 95% CI 1.04-1.36) and high-quality studies (RR: 1.22, 95% CI 1.14-1.31) showing an increased risk. Both NOS and GRADE assessments yielded mostly low to very low-quality results.

CONCLUSIONS

This review provides no clear evidence of an association between occupational exposure to benzene and the risk of male genital cancers. Subgroup analysis suggests an increased risk of prostate cancer in high-quality studies. Nevertheless, it is important to acknowledge the methodological limitations of the available studies. Further analyses including methodologically sound studies are needed to corroborate these findings.

Occupational benzene exposure and risk of kidney and bladder cancers: a systematic review and meta-analysis

INTRODUCTION

Benzene is recognized as leukemogenic. However, the association between it and solid cancers has been the subject of less investigation. We aim to conduct a systematic review and meta-analysis to evaluate the association between occupational exposure to benzene and the risk of urinary tract cancer, including kidney and bladder.

METHODS

We included 41 cohort and case-control studies listed in the most recent International Agency for Research on Cancer (IARC) Monograph on benzene exposure and the result of a literature review to identify more recent studies. Forest plots of relative risk (RR) were constructed for kidney, bladder, and urinary tract cancer overall. A random-effects model was used to address heterogeneity between studies. Stratified analyses were conducted to explore effect modification.

RESULTS

Our findings revealed an association between exposure to occupational benzene and kidney and unspecified urinary tract cancers (RR = 1.20, 95% confidence interval = 1.03-1.39), and an association of borderline statistical significance with bladder cancer (RR = 1.07, 95% confidence interval = 0.97-1.18). Publication bias was excluded for both kidney ( P  = 0.809) and bladder cancer ( P  = 0.748). Stratification analysis according to the selected study characteristics showed no difference except regarding the industry for kidney cancer ( P  < 0.000), with a stronger association in the chemical industry. An analysis by exposure level did not reveal any trend for kidney cancer, whereas there was a trend ( P  = 0.01) for bladder cancer.

CONCLUSION

Our study found an association between occupational benzene exposure and kidney cancer and a dose-effect association between benzene exposure and bladder cancer.

Occupational benzene exposure and risk of nervous system cancers: A systematic review and meta-analysis

BACKGROUND

Benzene is a solvent that has played a significant role in various industries and applications over time, but its use declined due to its carcinogenic nature. Classified as a human carcinogen since 1979, benzene exposure is linked to leukemia and possibly other cancers. The global rise of nervous system cancers urges investigation into the possible role of benzene. Our aim is to investigate this association through a systematic review and meta-analysis of occupational cohort and case-control studies.

METHODS

We registered our study protocol and followed established guidelines (Registration No. CRD42022379720). A systematic search across databases yielded 36 independent cohort and case-control studies. We conducted a random-effects meta-analysis of relative risks (RR) for nervous system cancers. Analyses were stratified based on various factors such as region, study design, and exposure level. Publication bias was evaluated using a funnel plot and Egger test.

RESULTS

Our meta-analysis indicates an association between benzene exposure and risk of overall nervous system cancers (RR = 1.21, 95 % confidence interval [CI] = 1.05-1.38). Stratified analyses showed an association with glioma (RR = 3.88, 95 % CI = 1.33-11.31, N risk estimates=2). Publication bias was detected (p = 0.01).

CONCLUSION

Our study found an association between occupational benzene exposure and increased risks of nervous system cancers, which however cannot be interpreted as causal. While these findings highlight the need for stringent safety measures, they also reveal gaps in literature. Further research is essential to address these limitations and deepen our understanding of benzene's health implications.

Occupational benzene exposure and colorectal cancer: A systematic review and meta-analysis

Recent reports suggest that benzene exposure may be associated with solid cancers, such as lung and bladder cancers. Instead, evidence on the association between benzene and colorectal cancer (CRC) is sparse. Thus, we aimed to summarize current literature on the association between occupational benzene exposure and CRC. We searched Pubmed, Embase (through Ovid), and Scopus to retrieve cohort and nested case-control studies on the association between occupational benzene exposure and solid cancers. The search was initially completed in December 2022 and later updated in April 2024. We assessed quality of included studies using a modified version of Newcastle-Ottawa Scale. We computed pooled relative risks (RRs) and corresponding 95% confidence intervals (CIs) of CRC according to occupational benzene exposure, using the Paule-Mandel method. Twenty-eight studies were included in the meta-analysis. Most of them were conducted in Europe or North America (82.1%) and were industry-based (89.3%). Pooled RRs comparing workers exposed to benzene with those who were unexposed for incidence and mortality were 1.10 (95% CI: 1.06, 1.15) and 1.04 (95% CI: 0.97, 1.11) for CRC, 1.12 (95% CI: 1.01, 1.24) and 1.08 (95% CI: 0.99, 1.19) for colon cancer, and 1.04 (95% CI: 0.94, 1.14) and 1.05 (95% CI: 0.92, 1.19) for rectal cancer, respectively. Only one study supported the occurrence of a dose-response relationship between occupational benzene exposure and CRC, while others found no increase in risk according to dose of exposure or duration of employment. Our findings suggest that occupational benzene exposure may be associated with CRC. Further research with detailed assessment of individual-level exposure is warranted to confirm our results.

Air pollution and kidney cancer risk: a systematic review and meta-analysis

BACKGROUND

Although several risk factors of kidney cancer have already been well-addressed, many remain underappreciated, such as chronic exposure to air pollution. This systematic review and meta-analysis aims to assess the association between air pollutant exposure and the risk of kidney cancer.

METHODS

With an exhaustive search equation including keywords related to air pollution and kidney cancer on EMBASE, PubMed, Web of science, Cochrane Library and CINAHL database, we identified all relevant articles published before March 23rd, 2023 (Prospero registration number: CRD42020187956). Using random-effects meta-analysis, we present pooled hazard ratios (with their respective 95% confidence interval) associated with a 10 µg/m3 increase in each pollutant level. Heterogeneity was quantified by the I2 statistic. Risks of methodological and publication bias were also both assessed using appropriate tools.

RESULTS

Of the 1919 records identified, our review included 19 articles (13 cohort, 5 registry-based and 1 case-control studies), of which 9 were suitable for the meta-analysis. We found a significantly increased risk of kidney cancer incidence for a 10 μg/m3 elevation of both particulate matter of less than 10 µm (PM10) (HR = 1.29 [1.10; 1.51], I2 = 0%, p = 0.002) and nitrogen dioxide (NO2) (HR = 1.10 [1.03; 1.18], I2 = 20%, p = 0.004). Secondary analyses also suggest an increased risk of kidney cancer-related morbidity-mortality associated with PM10 exposure.

CONCLUSIONS

Overall, our findings suggest a potential association between exposure to increased levels of PM10 and NO2 and the risk of kidney cancer. These results should nonetheless be interpreted with caution due to the limited number of included studies and their significant risk of methodological bias.

Particulate Matter 2.5 and Hematological Disorders From Dust to Diseases: A Systematic Review of Available Evidence

Particulate matter 2.5 (PM_2.5) in the air enters the human body by diffusion into the blood. Therefore, hematological abnormalities might occur because of these toxic particles, but few studies on this issue have been reported. According to Cochrane guidance, we performed a systematic review on the relationship between exposure to PM_2.5 and the risk of hematological disorders. Ten articles were included in this review. Anemia was found among children and elderly populations with 2- to 5-year PM_2.5 exposure. Young children from mothers exposed to air pollution during pregnancy had a higher incidence of leukemia similar to the elderly. Supporting these data, outdoor workers also showed abnormal epigenetic modifications after exposure to very high PM_2.5 levels. Adults living in high PM_2.5 areas for 2 years were more likely to develop thrombocytosis. Finally, elderly populations with 7- to 8-year PM_2.5 exposure showed increased risks of venous thromboembolism. In conclusion, the associations between PM_2.5 and hematological aberrations among high-risk people with long-term exposure were reported.

Assessment of hepatic functions, hematopoietic cytokines and haematological parameters in people occupationally exposed to volatile petroleum hydrocarbons

Humans are occupationally exposed to volatile petroleum hydrocarbons through inhalation and ingestion. To access the effect of exposure to volatile hydrocarbons, hematopoietic cytokines, haematological parameters and hepatic functions were assayed for in 100 subjects. Male participants showed significant increase (p < 0.05) in erythropoietin, interleukin-3, alanine transaminase (ALT), alkaline phosphatase (ALP), mean cell hemoglobin concentration (MCHC), mean cell volume (MCV) and significant decrease (p < 0.05) in mean cell hemoglobin (MCH). Female participants showed significant increase (p < 0.05) in interleukin-3, ALT, AST, ALP, MCHC, MCV and significant decrease (p < 0.05) in MCH, platelets, hemoglobin and hematocrit compared to their controls. Exposure to volatile petroleum hydrocarbons raised the absolute red blood cell indices and liver enzymes and could stimulate combined increase in the release of erythropoietin and interleukin-3 leading to ineffective hematopoiesis.

Combined Use of Diagnostic Fumarate Addition Metabolites and Genes Provides Evidence for Anaerobic Hydrocarbon Biodegradation in Contaminated Groundwater

The widespread use of hydrocarbon-based fuels has led to the contamination of many natural environments due to accidental spills or leaks. While anaerobic microorganisms indigenous to many fuel-contaminated groundwater sites can play a role in site remediation (e.g., monitored natural attenuation, MNA) via hydrocarbon biodegradation, multiple lines of evidence in support of such bioremediation are required. In this study, we investigated two fuel-contaminated groundwater sites for their potential to be managed by MNA. Microbial community composition, biogeochemical indicators, fumarate addition metabolites, and genes diagnostic of both alkane and alkyl-monoaromatic hydrocarbon activation were assessed. Fumarate addition metabolites and catabolic genes were detected for both classes of hydrocarbon biodegradation at both sites, providing strong evidence for in situ anaerobic hydrocarbon biodegradation. However, relevant metabolites and genes did not consistently co-occur within all groundwater samples. Using newly designed mixtures of quantitative polymerase chain reaction (qPCR) primers to target diverse assA and bssA genes, we measured assA gene abundances ranging from 10⁵–10⁸ copies/L, and bssA gene abundances ranging from 10⁵–10¹⁰ copies/L at the sites. Overall, this study demonstrates the value of investigating fuel-contaminated sites using both metabolites and genes diagnostic of anaerobic hydrocarbon biodegradation for different classes of hydrocarbons to help assess field sites for management by MNA.

Repetitive Detection of Aromatic Hydrocarbon Contaminants with Bioluminescent Bioreporters Attached on Tapered Optical Fiber Elements

In this study, we show the repetitive detection of toluene on a tapered optical fiber element (OFE) with an attached layer of Pseudomonas putida TVA8 bioluminescent bioreporters. The bioluminescent cell layer was attached on polished quartz modified with (3-aminopropyl)triethoxysilane (APTES). The repeatability of the preparation of the optical probe and its use was demonstrated with five differently shaped OFEs. The intensity of measured bioluminescence was minimally influenced by the OFE shape, possessing transmittances between 1.41% and 5.00%. OFE probes layered with P. putida TVA8 were used to monitor liquid toluene over a two-week period. It was demonstrated that OFE probes layered with positively induced P. putida TVA8 bioreporters were reliable detectors of toluene. A toluene concentration of 26.5 mg/L was detected after <30 min after immersion of the probe in the toluene solution. Additional experiments also immobilized constitutively bioluminescent cells of E. coli 652T7, on OFEs with polyethyleneimine (PEI). These OFEs were repetitively induced with Lauria-Bertani (LB) nutrient medium. Bioluminescence appeared 15 minutes after immersion of the OFE in LB. A change in pH from 7 to 6 resulted in a decrease in bioluminescence that was not restored following additional nutrient inductions at pH 7. The E. coli 652T7 OFE probe was therefore sensitive to negative influences but could not be repetitively used.

Voice and speech signs and symptoms in individuals exposed to chemical agents: an analysis of medical records

ABSTRACT Objective: to identify voice and speech signs and symptoms in patients exposed to chemical agents. Methods: an exploratory and descriptive study analyzing the data from the medical records of patients who sought health services at a toxicology outpatient clinic located in Southeastern Brazil. Results: a total of 139 medical records were obtained, 75 being selected. Twelve of the records selected contained data regarding voice and speech symptoms, including hoarseness (3), loss of voice (2), chronic throat inflammation (1), sore throat (1), secretion and burning in the throat (1), dry throat and mouth (1), lump in the throat associated with difficulty in swallowing (1), difficulty in articulating words (1), and difficulty in verbal expression (1). Diseases capable of causing phono-articulatory problems were detected in 6 cases. These symptoms affected individuals with occupational exposure to different substances, particularly community health agents (7) and pesticide applicators (7). Conclusion: individuals exposed to chemical substances experienced voice and speech problems, either due to a possible irritation caused by chemical agents or due to diseases developed during or after the exposure.

Occupational exposures to leaded and unleaded gasoline engine emissions and lung cancer risk

OBJECTIVES

To determine whether occupational exposure to gasoline engine emissions (GEE) increased the risk of lung cancer and more specifically whether leaded or unleaded GEE increased the risk.

METHODS

Two population-based case-control studies were conducted in Montreal, Canada. The first was conducted in the early 1980s and included many types of cancer including lung cancer. The second was conducted in the late 1990s and focused on lung cancer. Population controls were used in both studies. Altogether, there were 1595 cases and 1432 population controls. A comprehensive expert-based exposure assessment procedure was implemented and exposure was assessed for 294 agents, including unleaded GEE, leaded GEE and diesel engine emissions (DEE). Logistic regression analyses were conducted to estimate ORs between various metrics of GEE exposure and lung cancer, adjusting for smoking, DEE and other potential confounders.

RESULTS

About half of all controls were occupationally exposed to GEE. Irrespective of the metrics of exposure (any exposure, duration of exposure and cumulative exposure) and the type of lung cancer, and the covariates included in models, none of the point estimates of the ORs between occupational exposure to leaded or unleaded GEE and lung cancer were above 1.0. Pooling two studies, the OR for any exposure to leaded GEE was 0.82 (0.68-1.00).

CONCLUSIONS

Our results do not support the hypothesis that occupational exposure to GEE increases the risk of lung cancer.

Adverse Health Complaints of Adults Exposed to Benzene After a Flaring Disaster at the BP Refinery Facility in Texas City, Texas

OBJECTIVE

The objective of this study was to assess the adverse health symptoms experienced by adult subjects who were exposed to benzene after a flaring disaster at the BP refinery in Texas City, Texas.

METHODS

A total of 2162 adults aged 18 years or older and exposed to benzene were included. Using the patients' medical charts, we collected and analyzed data on health complaints as well as the patients' serum levels of beta-2-microglobulin and urinary excretion of phenol.

RESULTS

A total of 11,368 health symptom complaints were reported in 2162 adults exposed to benzene. Neurological symptoms occurred most frequently (174%), followed upper respiratory symptoms (115%), cough (31%), painful joints (30%), cardiac symptoms (28%), dermatological symptoms (28%), gastrointestinal symptoms (27%), diarrhea (25%), vision symptoms (21%), and nausea/vomiting (19%). Logistic regression analysis indicated that urinary symptoms (R2=0.65) and painful joints (R2=0.44) were positively associated with increasing age in benzene-exposed subjects.

CONCLUSION

Adult subjects exposed to benzene experience a range of adverse health symptoms and an altered profile of urinary phenol, thus indicating they are at high risk of developing serious future health complications. (Disaster Med Public Health Preparedness. 2018;12:232-240).

Outdoor air pollution and risk for kidney parenchyma cancer in 14 European cohorts

Several studies have indicated weakly increased risk for kidney cancer among occupational groups exposed to gasoline vapors, engine exhaust, polycyclic aromatic hydrocarbons and other air pollutants, although not consistently. It was the aim to investigate possible associations between outdoor air pollution at the residence and the incidence of kidney parenchyma cancer in the general population. We used data from 14 European cohorts from the ESCAPE study. We geocoded and assessed air pollution concentrations at baseline addresses by land-use regression models for particulate matter (PM10 , PM2.5 , PMcoarse , PM2.5 absorbance (soot)) and nitrogen oxides (NO2 , NOx ), and collected data on traffic. We used Cox regression models with adjustment for potential confounders for cohort-specific analyses and random effects models for meta-analyses to calculate summary hazard ratios (HRs). The 289,002 cohort members contributed 4,111,908 person-years at risk. During follow-up (mean 14.2 years) 697 incident cancers of the kidney parenchyma were diagnosed. The meta-analyses showed higher HRs in association with higher PM concentration, e.g. HR = 1.57 (95%CI: 0.81-3.01) per 5 μg/m3 PM2.5 and HR = 1.36 (95%CI: 0.84-2.19) per 10-5 m-1 PM2.5 absorbance, albeit never statistically significant. The HRs in association with nitrogen oxides and traffic density on the nearest street were slightly above one. Sensitivity analyses among participants who did not change residence during follow-up showed stronger associations, but none were statistically significant. Our study provides suggestive evidence that exposure to outdoor PM at the residence may be associated with higher risk for kidney parenchyma cancer; the results should be interpreted cautiously as associations may be due to chance.

Lymphohaematopoietic malignancies in Scottish military veterans: Retrospective cohort study of 57,000 veterans and 173,000 non-veterans

BACKGROUND

Lymphohaematopoietic malignancies are common in the general population. There have been concerns that military service may be associated with increased risk as a result of occupational exposures. To date, few studies have demonstrated an increased risk, although a disability pension is payable to veterans who were present at nuclear tests and who develop leukaemia (other than chronic lymphocytic leukaemia). The aim of the study was to utilise data from the Scottish Veterans Health Study to examine the risk of lymphohaematopoietic malignancy following military service in a large national cohort of veterans.

METHODS

Retrospective cohort study of 57,000 veterans and 173,000 non-veterans born between 1945 and 1985 matched for age, sex and area of residence, adjusted for areal deprivation and followed up for up to 30 years, using Cox proportional hazard models to compare the risk of lymphohaematopoietic malignancy overall, by diagnosis and by sex and birth cohort.

RESULTS

We found no statistically significant difference in risk between veterans and non-veterans either for all leukaemias (Cox proportional hazard ratio 1.03, 95% confidence intervals 0.84-1.27, p=0.773), Hodgkin lymphoma (hazard ratio 1.19, 95% confidence intervals 0.87-1.61, p=0.272) or for non-Hodgkin lymphoma (hazard ratio 0.86, 95% confidence intervals 0.71-1.04, p=0.110).

CONCLUSION

Our findings provide reassurance that service in the UK Armed Forces is not associated with increased risk of lymphohaematopoietic malignancy.

The micro-environmental impact of volatile organic compound emissions from large-scale assemblies of people in a confined space

Large-scale assemblies of people in a confined space can exert significant impacts on the local air chemistry due to human emissions of volatile organics. Variations of air-quality in such small scale can be studied by quantifying fingerprint volatile organic compounds (VOCs) such as acetone, toluene, and isoprene produced during concerts, movie screenings, and sport events (like the Olympics and the World Cup). This review summarizes the extent of VOC accumulation resulting from a large population in a confined area or in a small open area during sporting and other recreational activities. Apart from VOCs emitted directly from human bodies (e.g., perspiration and exhaled breath), those released indirectly from other related sources (e.g., smoking, waste disposal, discharge of food-waste, and use of personal-care products) are also discussed. Although direct and indirect emissions of VOCs from human may constitute <1% of the global atmospheric VOCs budget, unique spatiotemporal variations in VOCs species within a confined space can have unforeseen impacts on the local atmosphere to lead to acute human exposure to harmful pollutants.

Benzene Exposures and Risk Potential for Vehicle Mechanics from Gasoline and Petroleum-Derived Products

Benzene exposures among vehicle mechanics in the United States and abroad were characterized using available data from published and unpublished studies. In the United States, the time-weighted-average (TWA) airborne concentration of benzene for vehicle mechanics averaged 0.01-0.05 ppm since at least the late 1970s, with maximal TWA concentrations ranging from 0.03 to 0.38 ppm. Benzene exposures were notably lower in the summer than winter and in the Southwest compared to other geographic regions, but significantly higher during known gasoline-related tasks such as draining a gas tank or changing a fuel pump or fuel filter. Measured airborne concentrations of benzene were also generally greater for vehicle mechanics in other countries, likely due to the higher benzene content of gasoline and other factors. Short-term airborne concentrations of benzene frequently exceeded 1 ppm during gasoline-related tasks, but remained below 0.2 ppm for tasks involving other petroleum-derived products such as carburetor and brake cleaner or parts washer solvent. Application of a two-zone mathematical model using reasonable input values from the literature yielded predicted task-based benzene concentrations during gasoline and aerosol spray cleaner scenarios similar to those measured for vehicle mechanics during these types of tasks. When evaluated using appropriate biomarkers, dermal exposures were found to contribute little to total benzene exposures for this occupational group. Available data suggest that vehicle mechanics have not experienced significant exposures to benzene in the workplace, except perhaps during short-duration gasoline-related tasks, and full-shift benzene exposures have remained well below current and contemporaneous occupational exposure limits. These findings are consistent with epidemiology studies of vehicle mechanics, which have not demonstrated an increased risk of benzene-induced health effects in this cohort of workers. Data and information presented here may be used to assess past, current, or future exposures and risks to benzene for vehicle mechanics who may be exposed to gasoline or other petroleum-derived products.

Kidney cancer risk in oil refining in Finland: a nested case-referent study

OBJECTIVE

The purpose of this study was to assess whether occupational exposure to hydrocarbons in the oil-refining activity increases the risk of kidney cancer.

METHODS

This case-referent study was nested within the cohort of employees in the oil refinery industry in Finland in 1967 to 1982 (n = 9454). The final data included 30 cases of kidney cancer and 81 age- and sex-matched referents.

RESULTS

There was a threefold increase in the kidney cancer risk for exposure to hydrocarbons in crude oil (odds ratio, 3.1; confidence interval, 1.1 to 8.9; 11 exposed cases). The risk was associated with the highest cumulative exposure category to hydrocarbons in crude oil.

CONCLUSIONS

Occupational exposure in oil refining, particularly to crude oil, may increase kidney cancer risk. The study assessed historical exposures; further information needs to be collected for evaluating current exposures.

A retrospective cohort study of cause-specific mortality and incidence of hematopoietic malignancies in Chinese benzene-exposed workers

Benzene exposure has been causally linked with acute myeloid leukemia (AML), but inconsistently associated with other hematopoietic, lymphoproliferative and related disorders (HLD) or solid tumors in humans. Many neoplasms have been described in experimental animals exposed to benzene. We used Poisson regression to estimate adjusted relative risks (RR) and the likelihood ratio statistic to derive confidence intervals for cause-specific mortality and HLD incidence in 73,789 benzene-exposed compared with 34,504 unexposed workers in a retrospective cohort study in 12 cities in China. Follow-up and outcome assessment was based on factory, medical and other records. Benzene-exposed workers experienced increased risks for all-cause mortality (RR = 1.1, 95% CI = 1.1, 1.2) due to excesses of all neoplasms (RR = 1.3, 95% CI = 1.2, 1.4), respiratory diseases (RR = 1.7, 95% CI = 1.2, 2.3) and diseases of blood forming organs (RR = ∞, 95% CI = 3.4, ∞). Lung cancer mortality was significantly elevated (RR = 1.5, 95% CI = 1.2, 1.9) with similar RRs for males and females, based on three-fold more cases than in our previous follow-up. Significantly elevated incidence of all myeloid disorders reflected excesses of myelodysplastic syndrome/acute myeloid leukemia (RR = 2.7, 95% CI = 1.2, 6.6) and chronic myeloid leukemia (RR = 2.5, 95% CI = 0.8, 11), and increases of all lymphoid disorders included excesses of non-Hodgkin lymphoma (RR = 3.9, 95%CI = 1.5, 13) and all lymphoid leukemia (RR = 5.4, 95%CI = 1.0, 99). The 28-year follow-up of Chinese benzene-exposed workers demonstrated increased risks of a broad range of myeloid and lymphoid neoplasms, lung cancer, and respiratory diseases and suggested possible associations with other malignant and non-malignant disorders.

A case-control study of long-term exposure to ambient volatile organic compounds and lung cancer in Toronto, Ontario, Canada

Few studies have investigated associations between nonoccupational exposure to ambient volatile organic compounds and lung cancer. We conducted a case-control study of 445 incident lung cancers and 948 controls (523 hospital, 425 general population) in Toronto, Ontario, Canada, between 1997 and 2002. Participants provided information on several risk factors, including tobacco use, secondhand exposure to cigarette smoke, obesity, and family history of cancer. Exposure to benzene, hydrocarbons, and nitrogen dioxide was estimated using land-use regression models. Exposures were linked to residential addresses to estimate exposure at the time of interview, 10 years before interview, and across past residences (time-weighted average). Logistic regression was used to estimate adjusted odds ratios. Analyses involving the population-based controls found that an interquartile-range increase in the time-weighted average benzene concentration (0.15 µg/m(3)) across previous residences was associated with lung cancer (odds ratio = 1.84, 95% confidence interval: 1.26, 2.68). Similarly, an interquartile-range increase in the time-weighted average nitrogen dioxide concentration (4.8 ppb) yielded an odds ratio of 1.59 (95% confidence interval: 1.19, 2.12). Our study suggests that long-term exposure to ambient volatile organic compounds and nitrogen dioxide at relatively low concentrations is associated with lung cancer. Further work is needed to evaluate joint relationships between these pollutants, smoking, and lung cancer.

DNA-polyfluorophore Chemosensors for Environmental Remediation: Vapor-phase Identification of Petroleum Products in Contaminated Soil

Contamination of soil and groundwater by petroleum-based products is an extremely widespread and important environmental problem. Here we have tested a simple optical approach for detecting and identifying such industrial contaminants in soil samples, using a set of fluorescent DNA-based chemosensors in pattern-based sensing. We used a set of diverse industrial volatile chemicals to screen and identify a set of five short oligomeric DNA fluorophores on PEG-polystyrene microbeads that could differentiate the entire set after exposure to their vapors in air. We then tested this set of five fluorescent chemosensor compounds for their ability to respond with fluorescence changes when exposed to headgas over soil samples contaminated with one of ten different samples of crude oil, petroleum distillates, fuels, lubricants and additives. Statistical analysis of the quantitative fluorescence change data (as Δ(R,G,B) emission intensities) revealed that these five chemosensors on beads could differentiate all ten product mixtures at 1000 ppm in soil within 30 minutes. Tests of sensitivity with three of the contaminant mixtures showed that they could be detected and differentiated in amounts at least as low as one part per million in soil. The results establish that DNA-polyfluorophores may have practical utility in monitoring the extent and identity of environmental spills and leaks, while they occur and during their remediation.

An evidence-based analysis of epidemiologic associations between lymphatic and hematopoietic cancers and occupational exposure to gasoline

The presence of benzene in motor gasoline has been a health concern for potential increased risk of acute myelogenous leukemia and perhaps other lymphatic/hematopoietic cancers for approximately 40 years. Because of the widespread and increasing use of gasoline by consumers and the high exposure potential of occupational cohorts, a thorough understanding of this issue is important. The current study utilizes an evidence-based approach to examine whether or not the available epidemiologic studies demonstrate a strong and consistent association between occupational exposure to gasoline and lymphatic/hematopoietic cancers. Among 67 epidemiologic studies initially identified, 54 were ranked according to specific criteria relating to the relevance and robustness of each study for answering the research question. The 30 highest-ranked studies were sorted into three tiers of evidence and were analyzed for strength, specificity, consistency, temporality, dose-response trends and coherence. Meta statistics were also calculated for each general and specific lymphatic/hematopoietic cancer category with adequate data. The evidence-based analysis did not confirm any strong and consistent association between occupational exposure to gasoline and lymphatic/hematopoietic cancers based on the epidemiologic studies available to date. These epidemiologic findings, combined with the evidence showing relatively low occupational benzene vapor exposures associated with gasoline formulations during the last three decades, suggest that current motor gasoline formulations are not associated with increased lymphatic/hematopoietic cancer risks related to benzene.

[Cancers of the nasal cavity and paranasal sinuses: clinicopathological, etiological and therapeutic aspects]

Sinonasal cancers are rare and are often associated with occupational exposure that should be researched. Their diagnosis is often delayed. Carcinomas are the most common histological variety. The aim of the present report is to review the main scientific literature about sinonasal cancer to identify their clinicopathological features, and their main causes and treatment modalities. The treatment of these tumors is surgical, usually followed by radiotherapy.

Epidemiology of renal cell cancer

Renal cell cancer (RCC) is increasingly diagnosed at an early stage in many countries, which likely contributes to the recent leveling of RCC mortality in the United States and many European countries. However, over all stages nearly 50% of the patients die within 5 years after diagnosis. Smoking and obesity may account for approximately 40% of all incidental cases in high-risk countries. Besides obesity, rising prevalence of hypertension may play a growing role. Several other occupational and lifestyle factors may also affect the risk of RCC. Genetic variations may be an important factor in the differing incidence among populations.

Air pollution from traffic and cancer incidence: a Danish cohort study

BACKGROUND

Vehicle engine exhaust includes ultrafine particles with a large surface area and containing absorbed polycyclic aromatic hydrocarbons, transition metals and other substances. Ultrafine particles and soluble chemicals can be transported from the airways to other organs, such as the liver, kidneys, and brain. Our aim was to investigate whether air pollution from traffic is associated with risk for other cancers than lung cancer.

METHODS

We followed up 54,304 participants in the Danish Diet Cancer and Health cohort for 20 selected cancers in the Danish Cancer Registry, from enrolment in 1993-1997 until 2006, and traced their residential addresses from 1971 onwards in the Central Population Registry. We used modeled concentration of nitrogen oxides (NO(x)) and amount of traffic at the residence as indicators of traffic-related air pollution and used Cox models to estimate incidence rate ratios (IRRs) after adjustment for potential confounders.

RESULTS

NO(x) at the residence was significantly associated with risks for cervical cancer (IRR, 2.45; 95% confidence interval [CI], 1.01;5.93, per 100 μg/m(3) NO(x)) and brain cancer (IRR, 2.28; 95% CI, 1.25;4.19, per 100 μg/m(3) NO(x)).

CONCLUSIONS

This hypothesis-generating study indicates that traffic-related air pollution might increase the risks for cervical and brain cancer, which should be tested in future studies.

Occupational exposure to diesel and gasoline emissions and lung cancer in Canadian men

The International Agency for Research on Cancer classifies diesel exhaust as a probable human carcinogen; this decision is based largely from lung cancer evidence. Gasoline exhaust is classified as a possible carcinogen. Epidemiological studies are needed that improve upon some of the limitations of previous research with respect to the characterization of exposure, and the control for the potential confounding influence of smoking and other occupational exposures. Our objective was to investigate associations between occupational exposure to diesel and gasoline engine emissions and lung cancer. We used a case-control study design that involved men 40 years of age and older at the time of interview. Analyses are based on 1681 incident cases of lung cancer and 2,053 population controls. A self-reported questionnaire elicited a lifetime occupational history, including general tasks, and information on other potential risk factors. Occupational exposures to diesel and gasoline emissions, crystalline silica, and asbestos were assigned to each job held by study subjects by industrial hygienists who were blind to case-control status. Exposure metrics for diesel and gasoline emissions that were modeled included: ever exposure, cumulative exposure, and concentration of exposure. We found a dose-response relationship between cumulative occupational exposure to diesel engine emissions and lung cancer. This association was more pronounced for the squamous and large cell subtypes with adjusted odds ratios across the three increasing tertiles of cumulative lifetime exposure relative to those with no exposure of 0.99, 1.25, and 1.32 (p=0.04) for squamous cell carcinoma, and 1.06, 1.19, 1.68 (p=0.02) for large cell carcinoma. While the association with cumulative exposure to gasoline was weakly positive, it was not statistically significant. Our findings suggest that exposure to diesel engine emissions increases the risk of lung cancer particularly for squamous and large cell carcinoma subtypes.

Risk of leukemia as a result of community exposure to gasoline vapors: a follow-up study

OBJECTIVES

To assess the temporal and spatial relationship of risk for total leukemia and AML (acute myelogenous leukemia) among community residents of an area in northeastern (NE) Pennsylvania (PA) affected by the Tranguch Gasoline Spill which occurred in the early 1990s.

METHODS

Standardized incidence ratios (SIR) were calculated for total leukemia and AML among 625 residents affected by the gasoline spill in relation to both PA and local county cancer incidence rates. The risk of total leukemia and AML among the gasoline exposed population was evaluated for the period prior to the spill, 1985-1989; during the time surrounding the spill, 1990-1994; and for a period subsequent to the spill, 1995-2001.

RESULTS

The incidence of total leukemia and AML was significantly elevated subsequent to the spill for the entire period 1990-2001 and was highest for the period 1995-2001, whether comparison was made to PA or local county leukemia rates. Based on comparison to PA rates, the SIRs for total leukemia and AML were 7.69 (95% CI=1.58-22.46) and 11.54 (95% CI=2.38-33.69) for the 1995-2001 period, respectively. Prior to the spill, 1985-1989, and during the period of the spill, 1990-1994, no cases of leukemia were identified among the affected residents.

CONCLUSIONS

These results suggest a possible association between chronic low level benzene exposure and increased risk of leukemia among residents of the Tranguch Spill Site in NE PA. Our study provides additional support to the growing body of evidence implicating low level benzene exposure and cancer risk. We recommend that other communities contaminated with gasoline vapor through leaking underground storage vessels be monitored for elevated risk of leukemia.

Traffic air pollution and risk of death from gastric cancer in Taiwan: petrol station density as an indicator of air pollutant exposure

To investigate the relationship between air pollution and risk of death attributed to gastric cancer, a matched cancer case-control study was conducted using deaths that occurred in Taiwan from 2004 through 2008. Data for all eligible gastric cancer deaths were obtained and compared to a control group consisting of individuals who died from causes other than neoplasms and diseases that were associated with gastrointestinal (GIT) disorders. The controls were pair-matched to the cancer cases by gender, year of birth, and year of death. Each matched control was randomly selected from the set of possible controls for each cancer case. Data for the number of petrol stations in study municipalities were collected from two major petroleum supply companies. The petrol station density (per square kilometer) (PSD) for study municipalities was used as an indicator of a subject's exposure to benzene and other hydrocarbons present in ambient evaporative losses of petrol or to air emissions from motor vehicles. The exposed individuals were subdivided into three categories (≤25th percentile; 25th-75th percentile; >75th percentile) according to PSD in the residential municipality. Results showed that individuals who resided in municipalities with the highest PSD were at an increased risk of death attributed to gastric cancer compared to those subjects living in municipalities with the lowest PSD. The findings of this study warrant further investigation of the role of traffic air pollution exposure in the etiology of gastric cancer.

Assessing the impact of petrol stations on their immediate surroundings

This paper describes a novel methodology for evaluating the extent to which petrol stations affect their surroundings. The method is based on the fact that the ratio of the concentrations of aliphatic and aromatic hydrocarbon pollutants in the air of the petrol stations and their surroundings (basically determined by vapor emissions from unburned gasoline) differs from the ratio found in urban air, which is mainly influenced by traffic emissions. Bearing this in mind, the spatial limit of influence of petrol stations in any direction would be the first point, moving away from the station, where the ratio becomes equal to the urban background ratio. Application of the methodology involves multipoint measuring campaigns of the air at the studied petrol station and built-up area in general and processing the data with software capable of providing isoconcentration contours. The procedure should help local authorities in terms of land management, so that a "belt" can be established around petrol stations where housing or vulnerable populations and activities such as those in schools, hospitals and community centers should be restricted.

Occupational exposure to gasoline and the risk of non-Hodgkin lymphoma: a review and meta-analysis of the literature

AIMS

Gasoline comprises over 500 chemicals, including the known or suspected carcinogens benzene, 1,3-butadiene, ethylbenzene and methyl tert-butyl ether (MTBE). To assess whether work in the production, distribution and use of gasoline is associated with non-Hodgkin lymphoma (NHL), we reviewed the published literature on this topic.

METHOD

English-language peer-reviewed articles were identified by keyword searches of bibliographic databases. Twenty-two cohorts and thirteen case-control studies examined the risk of NHL among persons employed in the downstream petroleum industry.

RESULT

No positive associations were found with the exception of one study. The pooled risk estimate from a random-effects meta-analysis was 1.02 (95% confidence interval (CI) 0.94-1.12). Although there were no estimates available, exposure is likely to have varied by occupation, location and time period; there was no evidence however that risk estimates varied by any of these factors. NHL is a heterogeneous disease, yet no data were reported for NHL subtypes.

CONCLUSION

In summary, there is no suggestion across an extensive literature that exposure to gasoline at the levels workers' experience in an occupational setting increases the risk of NHL.

Direct detection of benzene, toluene, and ethylbenzene at trace levels in ambient air by atmospheric pressure chemical ionization using a handheld mass spectrometer

The capabilities of a portable mass spectrometer for real-time monitoring of trace levels of benzene, toluene, and ethylbenzene in air are illustrated. An atmospheric pressure interface was built to implement atmospheric pressure chemical ionization for direct analysis of gas-phase samples on a previously described miniature mass spectrometer (Gao et al. Anal. Chem.2006, 78, 5994-6002). Linear dynamic ranges, limits of detection and other analytical figures of merit were evaluated: for benzene, a limit of detection of 0.2 parts-per-billion was achieved for air samples without any sample preconcentration. The corresponding limits of detection for toluene and ethylbenzene were 0.5 parts-per-billion and 0.7 parts-per-billion, respectively. These detection limits are well below the compounds' permissible exposure levels, even in the presence of added complex mixtures of organics at levels exceeding the parts-per-million level. The linear dynamic ranges of benzene, toluene, and ethylbenzene are limited to approximately two orders of magnitude by saturation of the detection electronics.

Epidemiologic characteristics and risk factors for renal cell cancer

Incidence rates of renal cell cancer, which accounts for 85% of kidney cancers, have been rising in the United States and in most European countries for several decades. Family history is associated with a two- to four-fold increase in risk, but the major forms of inherited predisposition together account for less than 4% of renal cell cancers. Cigarette smoking, obesity, and hypertension are the most consistently established risk factors. Analgesics have not been convincingly linked with renal cell cancer risk. A reduced risk of renal cell cancer among statin users has been hypothesized but has not been adequately studied. A possible protective effect of fruit and vegetable consumption is the only moderately consistently reported dietary finding, and, with the exception of a positive association with parity, evidence for a role of hormonal or reproductive factors in the etiology of renal cell cancer in humans is limited. A recent hypothesis that moderate levels of alcohol consumption may be protective for renal cell cancer is not strongly supported by epidemiologic results, which are inconsistent with respect to the categories of alcohol consumption and the amount of alcohol intake reportedly associated with decreased risk. For occupational factors, the weight of the evidence does not provide consistent support for the hypotheses that renal cell cancer may be caused by asbestos, gasoline, or trichloroethylene exposure. The established determinants of renal cell cancer, cigarette smoking, obesity, and hypertension, account for less than half of these cancers. Novel epidemiologic approaches, including evaluation of gene–environment interactions and epigenetic mechanisms of inherited and acquired increased risk, are needed to explain the increasing incidence of renal cell cancer.

Exposure of petrol station attendants and auto mechanics to premium motor sprit fumes in Calabar, Nigeria

A population-based-cross-sectional survey was carried out to investigate the potential risk of exposure to premium motor spirit (PMS) fumes in Calabar, Nigeria, among Automobile Mechanics (AM), Petrol Station Attendants (PSA) and the general population. Structured questionnaire was administered on the randomly chosen subjects to elicit information on their exposure to PMS. Duration of exposure was taken as the length of work in their various occupations. Venous blood was taken for methaemoglobin (MetHb) and packed cells volume (PCV). Mean MetHb value was higher in AM (7.3%) and PSA (5.8%) than in the subjects from the general population (2.7%). PCV was lower in PSA (30.8%), than AM (33.3%) and the subjects from the general population (40.8%). MetHb level was directly proportional, and PCV inversely related, to the duration of exposure. The study suggested increased exposure to petrol fumes among AM, PSA, and MetHb as a useful biomarker in determining the level of exposure to benzene in petrol vapour.

Benzene activates caspase-4 and -12 at the transcription level, without an association with apoptosis, in mouse bone marrow cells lacking the p53 gene

Benzene is a well-known environmental pollutant that can induce hematotoxicity, aplastic anemia, acute myelogenous leukemia, and lymphoma. However, although benzene metabolites are known to induce oxidative stress and disrupt the cell cycle, the mechanism underlying lympho/leukemogenicity is not fully understood. Caspase-4 (alias caspase-11) and -12 are inflammatory caspases implicated in inflammation and endoplasmic reticulum stress-induced apoptosis. The objectives of this study were to investigate the altered expression of caspase-4 and -12 in mouse bone marrow after benzene exposure and to determine whether their alterations are associated with benzene-induced bone marrow toxicity, especially cellular apoptosis. In addition, we evaluated whether the p53 gene is involved in regulating the mechanism, using both wild-type (WT) mice and mice lacking the p53 gene. For this study, 8-week-old C57BL/6 mice [WT and p53 knockout (KO)] were administered a benzene solution (150 mg/kg diluted in corn oil) via oral gavage once daily, 5 days/week, for 1 or 2 weeks. Blood and bone marrow cells were collected and cell counts were measured using a Coulter counter. Total mRNA and protein extracts were prepared from the harvested bone marrow cells. Then qRT-PCR and Western blotting were performed to detect changes in the caspases at the mRNA and protein level, respectively. A DNA fragmentation assay and Annexin-V staining were carried out on the bone marrow cells to detect apoptosis. Results indicated that when compared to the control, leukocyte number and bone marrow cellularity decreased significantly in WT mice. The expression of caspase-4 and -12 mRNA increased significantly after 12 days of benzene treatment in the bone marrow cells of benzene-exposed p53KO mice. However, apoptosis detection assays indicated no evidence of apoptosis in p53KO or WT mice. In addition, no changes of other apoptosis-related caspases, such as caspase-3 and -9, were found in WT or p53KO mice at the level of mRNA and proteins. These results indicated that upregulation of caspase-4 and -12 in mice lacking the p53 gene is not associated with cellular apoptosis. In conclusion, caspase-4 and -12 can be activated by benzene treatment without inducing cell apoptosis in mouse bone marrow, which are partly under the regulation of the p53 gene.

Renal cancer

In Europe, renal cancer (that is neoplasia of the kidney, renal pelvis or ureter (ICD-9 189 and ICD-10 C64-C66)) ranks as the seventh most common malignancy in men amongst whom there are 29,600 new cases each year (3.5% of all cancers). Tobacco, obesity and a diet poor in vegetables are all acknowledged risk factors, along with specific occupational and environmental factors. A familial history of renal carcinoma is also likely to increase the risk. Renal carcinoma may remain clinically occult for most of its course. The classic presentation of pain, haematuria, and flank mass occurs in only 9% of patients and is often indicative of advanced disease. Approximately 30% of patients with renal carcinoma present with metastatic disease, 25% with locally advanced renal carcinoma and 45% with localized disease. Metastases are typically found in the lung, soft tissue, bone, liver, cutaneous sites, and central nervous system. The most important staging technique is a computed tomography (CT) scan of the whole abdomen. Survival rates are more favourable for patients with tumours confined to the kidney. Five-year survival for patients with metastatic renal carcinoma is comprised between 0 and 20%. Radical nephrectomy is the standard intervention for renal cancer. Intrinsic resistance to chemotherapy has long been a hallmark of renal carcinoma. Limited options are available for the systemic therapy, and no chemotherapeutic regimen is accepted as a standard of care. Biologic agents represent the major effective therapies for widespread metastatic renal cancer. An antiangiogenic strategy, the neutralization of VEGF, can slow the growth rate of advanced cancer.

Benzene-induced acute myeloid leukemia: a clinician's perspective

Benzene-induced acute myeloid leukemia (AML) is considered a secondary form of AML, based both in theory and on limited cohort observations. Its latency, cytogenetic aberrations, and clinical features are thought similar to, or identical with, AML resulting from the use of modern day cytotoxic agents for chemotherapy and immunotherapy. Although distinction between secondary AML and the far more common de novo AML is difficult to establish with certainty in any given case, latency from toxic therapeutic and environmental exposure and certain clinical and pathological features generally separate these two entities. AML is the only human neoplasm proven to be potentially caused by benzene, which actually is an obsolete form of chemotherapy. Despite many years of environmental regulation, alleged toxic exposure to this ubiquitous chemical has become an expanding area of litigation. A review of benzene-induced AML suggests that, in developed countries, this entity should no longer merit serious consideration among workers in the modern petrochemical industry and related fields.

Exposure to volatile organic compounds in an ethanol and gasoline service station

The present study was conducted to determine the VOCs concentrations in a service station located in a residential and commercial area in the city of Rio de Janeiro. This is, to our knowledge, the first published determination in Brazil, where both ethanol and ethanol-blended gasoline are used. Electro polished, stainless steel, evacuated canisters were used for sampling. The analysis was performed by gaschromatography with flame ionization detection (CG-FID) and by gas chromatography-mass spectrometry (CG-MS). A total of 80 and 56 compounds were determined in samples collected at the service station and control location, respectively. The most abundant compounds at the service station were in order of decreasing concentration (units: microg m(-3)): 2-methylbutane (1,715.7), 2-methylbut-1-ene (1,043.2), isobutene (758.8), 2-methylprop-1-ene (703.7), 2-methylpentane (492.1), pentadi-1,3-ene (189.7), toluene (157.0), benzene (144.5), but-2-ene (126.3) and m,p-xylene (123.2). A mean concentration of 144.5 microg m(-3) was determined for benzene, this value is about ten times the concentration determined in the control location in this work and about 70 times the value determined in other locations of Rio de Janeiro using charcoal cartridges for the sampling. The mean benzene/toluene ratios are 0.92 and 0.31 in the service station and control location, respectively. Since in Brazil service station workers are employed to fill customer's cars (self-service is not commonly used) the possible risk of cancer of these workers should be evaluated in a future study.

The non-Hodgkin lymphomas: a review of the epidemiologic literature

The non-Hodgkin lymphomas (NHL) are a heterogeneous group of B-cell and T-cell neoplasms that arise primarily in the lymph nodes. NHL incidence rates in the US doubled between about 1970 and 1990, and stabilized during the 1990s. NHL accounts for approximately 3.4% of cancer deaths in the US. Although some of the observed patterns in NHL have been related to HIV/AIDS, these conditions cannot fully explain the magnitude of the changes; neither do changes in classification systems nor improved diagnostic capabilities. Studies of occupational and environmental exposures (e.g., pesticides, solvents) have produced no consistent pattern of significant positive associations. Inverse associations with ultraviolet radiation exposure and alcohol and fish intake, and positive associations with meat and saturated fat intake have been reported in several studies; additional studies are needed to confirm or refute these associations. Family history of NHL or other hematolympho-proliferative cancers and personal history of several autoimmune disorders are associated with increased risk of NHL, but are not likely to account for a large proportion of cases. HIV and other infectious agents, such as human herpesvirus 8 and Epstein-Barr, appear to be associated with differing types of NHL, such as some B-cell lymphomas. Future epidemiologic studies should evaluate associations by NHL type, enhance exposure information collected, and elucidate factors that may identify susceptible (or resistant) subpopulations because of genetic, immunologic or other characteristics. The extent to which the etiology of NHL types may differ is important to resolve in ongoing and future studies.

Multiple myeloma: A review of the epidemiologic literature

Multiple myeloma, a neoplasm of plasma cells, accounts for approximately approximately 15% of lymphatohematopoietic cancers (LHC) and 2% of all cancers in the US. Incidence rates increase with age, particularly after age 40, and are higher in men, particularly African American men. The etiology is unknown with no established lifestyle, occupational or environmental risk factors. Although several factors have been implicated as potentially etiologic, findings are inconsistent. We reviewed epidemiologic studies that evaluated lifestyle, dietary, occupational and environmental factors; immune function, family history and genetic factors; and the hypothesized precursor, monoclonal gammopathies of undetermined significance (MGUS). Because multiple myeloma is an uncommon disease, etiologic assessments can be difficult because of small numbers of cases in occupational cohort studies, and few subjects reporting exposure to specific agents in case-control studies. Elevated risks have been reported consistently among persons with a positive family history of LHC. A few studies have reported a relationship between obesity and multiple myeloma, and this may be a promising area of research. Factors underlying higher incidence rates of multiple myeloma in African Americans are not understood. The progression from MGUS to multiple myeloma has been reported in several studies; however, there are no established risk factors for MGUS. To improve our understanding of the causes of multiple myeloma, future research efforts should seek the causes of MGUS. More research is also needed on the genetic factors of multiple myeloma, given the strong familial clustering of the disease.

Occupational kidney cancer: exposure to industrial solvents

We report seven cases of renal cell carcinoma in workers diagnosed with occupational exposure via skin contact and inhalation to industrial solvents containing benzene. The clinical significance of these cases are: (a) all seven patients diagnosed with kidney cancer were seen by private physicians who missed addressing occupational history to industrial solvents; (b) emphasize the importance of taking an in-depth history including occupational history in any patient presented to the clinician, especially like in these cases, kidney cancer; and (c) demonstrate the importance of educating workers. We believe that there exist more patients with renal cancer whose diagnosis has been rendered "idiopathic" due to the lack of detailed occupational, environmental, personal, and family history.

Benzene metabolites induce apoptosis in lymphocytes

Benzene is an important environmental pollutant with important health implications. Exposure to this aromatic hydrocarbon is associated with hematotoxicity, and bone marrow carcinogenic effects. It has been shown that benzene induces oxidative stress, cell cycle alterations, and programmed cell death in cultured cells. Hepatic metabolism of benzene is thought to be a prerequisite for its bone marrow toxicity. Nevertheless, there are no reports on the cellular effects of reactive intermediates derived from hepatic metabolism of benzene. Thus, the goal of this project was to determine the cellular alterations of benzene metabolites produced by the cultured hepatic cell line HepG2. Supernatants collected from these cells were applied to a culture of freshly isolated lymphocytes. A higher decrease in cell viability was found in cells exposed to these supernatants than to unmetabolized benzene. This viability decrease was due to apoptosis, as determined by Terminal deoxynucleotidyl Transferase Biotin-dUTP Nick End Labeling (TUNEL) assay and internucleosomal fragmentation of DNA. When supernatants were analyzed by HPLC, we found that not all the hydrocarbon was biotransformed, since a 28 microM concentration (37%) remained. The only metabolite found in the culture medium was muconic acid. The present results show that muconic acid derived from benzene metabolism is able to cooperate with the pollutant for the induction of apoptosis in rat lymphocytes.