Epidemiological studies have demonstrated an association between long-term exposure to inorganic arsenic and the related adverse effects such as cancers, skin lesions, and vascular diseases. Although several hypotheses have been proposed for the mechanism of arsenic-induced pathogenesis, it remains imperfectly understood. Recent studies have suggested that alterations in growth signal transduction pathways, particularly involving transforming growth factor-alpha (TGF-alpha), may be important. Immunoassays were used to determine the plasma levels of TGF-alpha and epidermal growth factor receptor (EGFR), which is the receptor for TGF-alpha, in residents of an arseniasis area of Taiwan in relation to their estimated cumulative arsenic exposure from drinking water. No relationship between arsenic exposure and EGFR was found. However, among the high cumulative exposure group ( > 6 ppm-years), levels of plasma TGF-alpha (25.5 +/- 38.2 pg ml(-1)) and the proportion of individuals with TGF-alpha over-expression (29.4%) were significantly higher (p < 0.05) than normal, healthy unexposed controls (8.1 +/- 5.6 pg ml(-1), 8.6%, respectively). There was a significant linear trend between cumulative arsenic exposure and the prevalence of plasma TGF-alpha over-expression after adjusting for age and sex (p = 0.019). The results suggest that plasma TGF-alpha expression may be a useful biomarker when detecting adverse effects on arsenic exposed population.

Recent evidence suggests that the development of skin lesions from arsenic exposure may be mediated by increases in the expression of various growth factors, including transforming growth factor-alpha (TGFα). To investigate this association in humans, levels of total urinary arsenic and urinary TGFα were determined in 41 individuals with and without arsenic-associated skin lesions from Bangladesh who have chronic exposure to arsenic in their drinking water. After adjusting for age and sex, total urinary arsenic was found to be correlated with urinary TGFα (R 2 = 0.37; p < 0.0001), particularly in those individuals with arsenic-associated skin lesions (R 2 = 0.70; p < 0.0001). Stratification of the cohort into quartiles based on urinary TGFα levels demonstrated a trend of increasing odds ratios for the presence of arsenic-associated skin lesions with increasing urinary TGFα, although this was not significant (p = 0.15). These results suggest that urinary TGFα may be a useful biomarker for the epidermal effects of arsenic exposure.

The present study examined the associations between drinking water and urinary arsenic levels and skin lesions among 167 residents of three contiguous villages in Bangladesh. Thirty-six (21.6%) had skin lesions (melanosis, hyperkeratosis, or both), of which 13 (36.1%) occurred in subjects who were currently drinking water containing concentrations of arsenic < 50 micrograms/L. The risk for skin lesions in relation to the exposure estimates based on urinary arsenic was elevated more than 3-fold, with the odds ratios for the highest versus the lowest quartiles being 3.6 (95% confidence interval, 1.2 to 12.1) for urinary total arsenic and 3.2 (95% confidence interval, 1.1 to 10.0) for urinary creatinine-adjusted total arsenic. The risks for skin lesions in relation to the exposure estimates based on arsenic in drinking water were less strongly elevated, with the odds ratios for the highest versus the lowest quartiles of exposure being 1.7 (95% confidence interval, 0.6 to 5.1) for drinking-water arsenic and 2.3 for cumulative arsenic index. The study suggests that arsenic exposure is associated with skin lesions in the Bangladesh population and that urinary arsenic may be a stronger predictor of skin lesions than arsenic in drinking water in this population.

Serum samples from the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study were used in a nested case control study to identify the possible association between the serum level of epidermal growth factor receptor and p53 in respect to lung cancer. The proteins were assayed for by commercial immunoassays that showed uneven, often unacceptable, quality. For EGFR there was no relationship to lung cancer. Two physiological variables appeared to modify the serum level of EGFR, age by decreasing it annually by about 4 fmolml-1, and stroke by increasing it by 150 fmolml-1. For p53, myocardial infarction appeared to cause an increase in serum levels of this protein. While the serum levels of p53 were only moderately increased in lung cancer patients, particularly those with squamous cell carcinoma, the intriguing findings related to the high frequency of p53-positive patients among those belonging to the group of patients being treated by surgery and those belonging to clinical stages 1 and 2 as compared with higher clinical stages. An untested rationalization of these results was that patients with advanced lung cancer, stages 3 and higher, develop autoantibodies against the mutant p53 and thus mask the serum levels of the mutant p53 protein.

Animal models suggest that dioxins have a negative effect on the level of expression of the epidermal growth factor receptor in cells. In vivo the level of expression in tissue of the epidermal growth factor receptor can be monitored by assaying for the extracellular domain in blood using an enzyme linked immunosorbent assay. We have determined the levels of the extracellular domain of the epidermal growth factor receptor in the plasma of 30 individuals: 10 with high blood dioxin levels (TEQ range = 318-673 ppt), 10 with medium blood dioxin levels (TEQ range = 16-60 ppt), and 10 with low background blood dioxin levels (TEQ range = 3-10 ppt). The levels of the epidermal growth factor receptor extracellular domain were lower in the high blood dioxin group (mean +/- SD = 45 +/- 26 fmol/ml) and the medium blood dioxin group (mean +/- SD = 41 +/- 23 fmol/ml) compared with the low blood dioxin group (mean +/- SD = 73 +/- 43 fmol/ml). These results suggest that the extracellular domain of the epidermal growth factor receptor may be a marker of the biological effect of dioxin exposure.

To the Editor: The production of specific point mutations in the p53 tumor suppressor gene, as can be induced by certain chemical carcinogens, is believed to contribute to the development of some occupational cancers. A model system for studying this process in vivo in humans is provided by workers who have been occupationally exposed to high levels of vinyl chloride (VC) and are at risk for the development of the sentinel neoplasm, angiosarcoma of the liver (ASL). This is because of the fact that the active metabolites of VC are known to form stable etheno-adenosine adducts in DNA that could result in A → T transversions. Such A → T transversions have been found in the DNA from two of four ASLs in VC-exposed workers studied to date (at the first base of codons 249 and 255),1 and similar mutations have not been identified in non-VC-induced ASLs.2 These mutations would result in amino acid substitutions in the encoded p53 proteins (Arg → Trp at 249 and Ile → Phe at 255). These amino acid substitutions occur in a highly conserved region of p53 that is believed to be critical to its tumor-suppressor function. Similar amino acid substitutions in this region of p53 occur frequently in human cancers and are thought to contribute to the development of the cancers. In certain cases, such amino acid substitutions produce a conformational change in the p53 protein that stabilizes the mutant protein from intracellular degradation (which is rapid for the wild-type protein, which has a short half-life), extending the half-life and resulting in intranuclear accumulations of the mutant protein. Such mutant p53 can be demonstrated by the use of a specific mouse monoclonal antibody (PAb240), which identifies an epitope between amino acids 212 and 217 that is normally concealed in the wild-type p53 but which is revealed in many mutant p53 proteins because of the aforementioned conformational changes produced in the mutants. We have been able to use a previously described enzyme-linked immunosorbent assay (ELISA) based on PAb240 3 to detect increased amounts of the mutant p53 protein (up to 0.84 ng/mL) in the extracellular supernatant of cells in culture (SW480) known to contain increased amounts of the mutant p53. This suggests that in a similar situation in vivo, in which individuals have tumors that contain p53 mutations, increased amounts of mutant p53 protein may be detectable in easily accessible extracellular biological fluids such as serum. Therefore, we have examined the expression of mutant p53 protein in 29 individuals from a previously described cohort of VC-exposed workers and unexposed control subjects.4 This group included: four VC-exposed workers with ASLs (two with p53 mutations and two without p53 mutations), one VC-exposed worker with hepatocellular carcinoma (HCC) without a p53 mutation, 18 VC exposed workers without ASLs, and five unexposed control subjects group-matched for age, sex, and race. In these individuals, tumor-tissue was analyzed by immunohistochemistry by using a modification of the technique of Cattoretti et al5 with mouse monoclonal antibody DO-1, and serum was analyzed by ELISA based on PAb240 as described previously.3 The two of four cases of ASL (50%) that were known to contain p53 mutations in their tumor DNA were found to have increased amounts of mutant p53 protein in their tumor tissue and serum, whereas the two cases of ASL and one case of HCC that were known not to contain p53 mutations in their tumor DNA were found not to have increased amounts of mutant p53 protein in their tumor tissue or serum. Because these results suggested that serum mutant p53 could be a valid surrogate for mutant p53 gene expression in tissue, we examined the serum mutant p53 in the 18 VC-exposed workers without ASLs and the five control subjects. Three of 18 exposed workers (16%) had elevated serum mutant p53, compared with none of the control subjects. All of the five p53 serum-positive individuals in this group had histories of potential high exposure to VC (greater than 10 years of work in an exposed job category and an estimated total dose greater than 1500 ppm-year), whereas the VC-exposed workers with lesser exposure were all serum-negative. These results suggest that the detection of serum mutant p53 protein may be a useful biomarker for the study of VC-induced carcinogenesis in exposed human populations. Steven J. Smith, MPH; Jiin-Chyuan Luo, MD, DrPH; Paul Brandt-Rauf, ScD, MD, DrPH Division of Environmental Health Sciences; Columbia University School of Public Health; New York, NY Marie-Jeanne Marion, PhD INSERM; Lyon, France

This exposure assessment pilot study tested the hypothesis that elevated blood levels of the dioxin congener 2,3,7,8-TCDD ("TCDD"), due to Agent Orange exposure, in American Vietnam veterans could be demonstrated two to three decades after Vietnam service. A second objective was to determine if dioxins, including TCDD, are present in the semen of adult males. In the early 1990s, blood samples from 50 Vietnam veterans and three pooled semen samples from 17 of them were analyzed by high-resolution gas chromatography-mass spectroscopy for dioxins, dibenzofurans, and the dioxin-like PCBs. Fifty volunteers from the Michigan Vietnam veteran bonus list, which documented Vietnam service, were invited to participate based on their self-reported exposure to Agent Orange in Vietnam. Screening of military and medical records was performed by an epidemiologist and a physician to assure that Agent Orange exposure was possible based on job description, location of service in Vietnam, and military Agent Orange spray records. Elevated 2,3,7,8-TCDD levels, over 20 ppt on a lipid basis, could still be detected in six of the 50 veterans in this nonrandomly selected group. The dioxin and dibenzofuran congeners commonly found in the U.S. population, including TCDD, were also detected in the three pooled semen samples. Quantification and comparison on a lipid basis were not possible due to low lipid concentrations where levels were below the detection limit. Therefore, semen samples were measured and reported on a wet-weight basis. Elevated blood TCDD levels, probably related to Agent Orange exposure, can be detected between two and three decades after potential exposure in some American veterans. Original levels were estimated to be 35-1,500-fold greater that that of the general population (4 ppt, lipid) at the time of exposure. In addition, the detection of dioxins in semen suggests a possible mechanism for male-mediated adverse reproductive outcomes following Agent Orange or other dioxin exposure.

OBJECTIVES:Increased concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzo-furans (PCDFs) in pooled blood samples from workers at municipal waste incinerators have been reported. This study was undertaken to confirm these results in individual blood samples from potentially exposed and unexposed workers at municipal waste incinerators compared with matched unexposed controls and compared with concentrations in the slag and fly ash from the municipal waste incinerators.METHODS:Concentrations of PCDDs and PCDFs were determined in the blood of 10 workers from an old municipal waste incinerator without adequate pollution controls, 11 workers from a newer incinerator with modern pollution controls, and 25 controls from the general population group matched for age (+/- 10 years), sex, and race, and in the slag and fly ash from the older incinerator.RESULTS:Significant increases of certain PCDDs and PCDFs were found in the blood of the workers from the older incinerator compared with the controls as follows: octaCDD (1051 (438) v 637 (344), P < 0.001), hexaCDF (52.3 (28.7) v 30.2 (18.2), P < 0.01), heptaCDF (43.9 (30.4) v 22.7 (12.4), P < 0.001), total PCDDs (1262 (484) v 825 (454), P < 0.001), total PCDFs (133.0 (68.1) v 93.7 (36.7), P < 0.05), and total PCDD/Fs (1395 (537) v 918 (437), P < 0.001). The workers from the older incinerator with the greatest exposure were found to have the most significant increases of the blood PCDDs and PCDFs, and the pattern of increased PCDD and PCDF congeners in the blood corresponded to the pattern in the incinerator slag and ash. No significant differences were found between the blood concentrations of the workers at the newer incinerator and the controls.CONCLUSION:Occupational exposure to slag and fly ash from municipal waste incinerators may increase the blood concentrations of PCDDs and PCDFs. Modern pollution control technology in new incinerators may be able to minimise potential exposure to slag and fly ash and thus the absorption of PCDDs and PCDFs from this source.

Teichman, Ron; Cassidy, Susan O.; Brandt-Rauf, Paul; Wester, Mary Sue; Canella, Joseph; Goldberg, Robert; Gresch, Elizabeth Author Information

Using ELISAs, we determined the concentrations of transforming growth factor alpha (TGF-alpha), the extracellular domain of the erbB-2 receptor (erbB-2 ECD), and mutant p53 protein in stored serum samples of asbestosis patients with and without cancer and control subjects (without asbestosis or cancer). The percentage of individuals in these three groups with increased serum concentrations of TGF-alpha, erbB-2 ECD, and mutant p53, respectively, were: asbestosis patients with cancer, 36%, 16%, 19%; asbestosis patients without cancer, 38%, 19%, 6%; control subjects, 0%, 5%, 10%. Although differences in serum positivity for these oncoproteins were apparent among these groups, the differences did not achieve statistical significance (P > 0.05). In several of the cancer cases, increased concentrations of TGF-alpha, erbB-2 ECD, and mutant p53 were also detected in the stored serum samples collected years before the clinical diagnosis of disease.

With substantial improvements in analytic techniques over the past decade, it has become possible to measure polychlorinated dioxins (PCDDs) and dibenzofurans (PCDFs) in human tissue in a congener-specific fashion down to the low parts per trillion level. This paper reviews findings using these new techniques from a number of recent medical and environmental case studies. These studies include those of workers exposed to a polychlorinated biphenyl (PCB) transformer fire in the United States, German chemical workers exposed to 2,3,7,8-tetrachlorodibenzodioxin (2,3,7,8-TCDD) while cleaning up after an explosion, workers at a municipal incinerator in New York City, a chemist exposed to brominated and chlorinated dioxins, U.S. veterans and also Vietnamese civilians exposed to Agent Orange contaminated with TCDD in Vietnam, and victims of the polychlorinated dibenzofuran and PCB contaminated rice oil (Yusho) incident in Japan.

A cohort of asbestosis patients at high risk for cancer was investigated by the means of epidermal growth factor receptor and Neu oncoprotein levels in serum. The samples were collected between 1981 and 1987 from 111 asbestosis patients. X-ray pictures, taken three times during this period of time, were evaluated according to the ILO classification to deduce the severity of the disease (stable, unstable) and compared side by side to determine the progression of asbestosis. Follow-up of these patients until 1993 showed that 38 patients had developed cancer (27 lung, 3 pleural mesothelioma, 8 diverse malignancies). As determined by ELISA for EGFR and two different assays for Neu oncoprotein (Neu, nNeu) there was a statistically significant difference between EGFR levels in all the cancer and the non-lung cancer cases compared with the controls. No statistically significant differences were detected between Neu levels in the cancer cases and the controls. Protein concentrations showed no change prior the diagnosis of cancer. The serum levels of the proteins correlated with each other (EGFR-Neu, r=0.3; Neu-nNeu, r=0.7). Among 9 factors that were analyzed by multiple regression analysis progressive asbestosis was statistically significantly associated with the elevation of Neu and smoking with the elevation of nNeu. In logistic regression analysis only unstable asbestosis associated with cancer (OR = 6.25, p=0.0012). This study shows a coherence between the severity of asbestosis and development of cancer. Furthermore, the Neu concentration in the serum was elevated in both unstable and progressive asbestosis cases and may offer tools, supplementary to X-rays, for clinical monitoring of the pneumoconiosis patients.

OBJECTIVES. Analysis of data from the New York City Fire Department showed that residential fuel oil releases frequently occur in quantities ranging from 5 to 1000 gal, primarily from storage tank leaks and overfill. A risk assessment was conducted to determine whether Number 2 fuel oil basement spills pose a significant risk to human health. METHODS. Exposure was derived from a simulated field study spill of Number 2 fuel oil in a townhouse basement to develop emission rates for the indicator constituent xylene. Distribution of xylene throughout the townhouse was determined using a multizone contaminant dispersal model. RESULTS. Spills of 85 and 21 gal resulted in xylene exposure estimates as high as 20 and 5 mg/kg/day, respectively. CONCLUSIONS. A spill of about 21 gal or more of Number 2 fuel oil would present a human health risk for central nervous and reproductive systems for 8 days or longer. Tank inspection and supervised delivery would provide effective prevention at minimal expense.

EXTREME environmental pollution such as that found in the highly industrialized Silesian region of Poland has been associated with increased risk of cancer and adverse reproductive outcomes1,2. Among the most prevalent carcinogenic and mutagenic air pollutants in Silesia are the polycyclic aromatic hydrocarbons (PAH) which are largely produced by industrial and residential combustion of coal1. Molecular epidemiology aims to prevent disease by using biological markers to identify risks well before clinicai onset to allow effective intervention3-7. Here, we use a battery of biological markers to measure molecular and genetic damage in peripheral blood samples from residents of Silesia and from persons living in a rural, less polluted area of Poland. The results show that their exposure to environmental pollution is associated with significant increases in carcinogen-DNA adducts (PAH-DNA and aromatic adducts), in sister chromatid exchange including high-frequency cells, and in chromosomal aberrations as well as a doubling in the frequency of ras oncogene overexpression. We found that aromatic adducts on DNA were significantly correlated with chromosomal mutation, providing us with a molecular link between environmental exposure and a genetic alteration relevant to cancer and reproductive risk.

Firefighters are potentially at increased risk for cancer and non-malignant respiratory disease due to their toxic exposures on the job. Growth factors and oncogene proteins are thought to play a role in the development of various malignancies and pulmonary fibrotic diseases. Therefore, a cohort of firefighters and matched controls have been screened for the presence of nine different growth factors and oncoproteins using an immunoblotting assay. Fourteen of the firefighters were found to be positive for beta-transforming growth factor (beta-TGF) related proteins compared to no positives in the controls (P = 0.0017). These results suggest that beta-TGF may be a possible biomarker for monitoring firefighters and other exposed workers for the potential development of cancer or non-malignant respiratory disease.

Questions have been raised concerning the safety of mass burn incineration and its role in solid waste management. In 1989, the New York City Office of Occupational Safety and Health examined air levels of metals in New York City incinerators and found that workers were exposed to air lead levels as high as 2500 micrograms/m3 while cleaning the electrostatic precipitators in the plant. In order to determine the biologic significance of these exposures to the workers, blood samples were taken from 56 incinerator workers and 25 controls and analyzed for lead and erythrocyte protoporphyrin levels. Incinerator workers were found to have a mean blood lead of 11.0 micrograms/dl as compared to the control group level of 7.4 micrograms/dl. Risk factors for increased blood lead levels were analyzed using multiple regression analyses. Wearing a personal protective device "always" or not and the interaction of smoking and cleaning the precipitator more than seven times in the past year were found to be significant predictors for blood lead. These results indicate that lead in municipal incinerator ash from electrostatic precipitators is bioavailable and that the effects of such exposure can be minimized by wearing personal protective devices, not smoking, and rotating the work force to minimize precipitator ash contact.