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Occupational exposure to the arylamines benzidine and β -naphthylamine increase bladder cancer risk up to 100-fold, making them some of the most powerful human carcinogens. We hypothesize that tumors arising in people with occupational exposures have different patterns of gene expression than histologically similar tumors from people without such exposures. In a case-case study, we compare gene expression in 22 formalin-fixed paraffin-embedded (FFPE) bladder tumors from men with high-level occupational exposure to arylamines to that in 26 FFPE bladder tumors from men without such exposure. Gene expression analysis was performed on the NanoString nCounter system using a PanCancer Progression Panel comprised of 740 cancer progression-related genes and a custom panel of 69 arylamine- and bladder cancer-related genes which were chosen from in vitro studies. Although fold differences were small, there was evidence of differential expression by exposure status for 17 genes from the Progression Panel and 4 genes from the custom panel. In total, 10 genes showed dose-response association at a p < 0.01, of which 4 genes ( CD46 , NR4A1 , BAX , and YWHAZ ) passed a false discovery rate (FDR) q value cutoff of 0.05 but were not significant after Bonferroni correction. Overall, we find limited evidence for differentially expressed genes in pathways related to DNA damage signaling and epithelial-to-mesenchymal transition (EMT)., Competing Interests: The authors declare no conflicts of interest with respect to the research, authorship, and/or publication of this article., (Copyright © 2021 Ramya T. Kolli et al.)

Phthalate plasticizers such as di(2-ethylhexyl) phthalate (DEHP) are being phased out of many consumer products because of their endocrine disrupting properties and their ubiquitous presence in the environment. The concerns raised from the use of phthalates have prompted consumers, government, and industry to find alternative plasticizers that are safe, biodegradable, and have the versatility for multiple commercial applications. We examined the toxicogenomic profile of mono(2-ethylhexyl) phthalate (MEHP, the active metabolite of DEHP), the commercial plasticizer diisononyl cyclohexane-1,2-dicarboxylate (DINCH), and three recently proposed plasticizers: 1,4-butanediol dibenzoate (BDB), dioctyl succinate (DOS), and dioctyl maleate (DOM), using the immortalized TM4 Sertoli cell line. Results of gene expression studies revealed that DOS and BDB clustered with control samples while MEHP, DINCH and DOM were distributed far away from the control-DOS-BDB cluster, as determined by principle component analysis. While no significant changes in gene expression were found after treatment with BDB and DOS, treatment with MEHP, DINCH and DOM resulted in many differentially expressed genes. MEHP upregulated genes downstream of PPAR and targeted pathways of cholesterol biosynthesis without modulating the expression of PPAR's themselves. DOM upregulated genes involved in glutathione stress response, DNA repair, and cholesterol biosynthesis. Treatment with DINCH resulted in altered expression of a large number of genes involved in major signal transduction pathways including ERK/MAPK and Rho signalling. These data suggest DOS and BDB may be safer alternatives to DEHP/MEHP than DOM or the commercial alternative DINCH.

Our study describes the discovery of a series of highly potent hepatitis C virus (HCV) NS5A inhibitors based on symmetrical prolinamide derivatives of benzidine and diaminofluorene. Through modification of benzidine, l-proline, and diaminofluorene derivatives, we developed novel inhibitor structures, which allowed us to establish a library of potent HCV NS5A inhibitors. After optimizing the benzidine prolinamide backbone, we identified inhibitors embedding meta-substituted benzidine core structures that exhibited the most potent anti-HCV activities. Furthermore, through a battery of studies including hERG ligand binding assay, CYP450 binding assay, rat plasma stability test, human liver microsomal stability test, and pharmacokinetic studies, the identified compounds 24, 26, 27, 42, and 43 are found to be nontoxic, and are expected to be effective therapeutic anti-HCV agents., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)

Aim: To describe the epidemiology, the risk and genetic factors involved in carcinogenesis pathways of upper urinary tumors UTUCs., Material: A systematic review of the scientific literature was performed from the database Medline (National Library of Medicine, PubMed) and websites of the HAS and the ANSM using the following keywords: epidemiology; risk factor; tobacco; aristolochic acid; urothelial carcinoma; ureter; renal pelvis. The search was focused on the characteristics, the mode of action, the efficiency and the side effects of the various drugs concerned., Results: The estimated UTUC incidence is 1.2 cases/100,000 inhabitant per year in Europe. The incidence of renal pelvis tumor has been stable for 30years, while the frequency of ureteric locations has increased over time. Locally advanced stage and high grade are more frequent at the time of diagnosis. The median age for diagnosis is 70-years-old. Male-to-female ratio is nearly 2. Main carcinogenic factors are tobacco consumption and occupational exposure. There are specific risk factors for UTUC such acid aristolochic (balkan's nephropathy and Chinese herbs nephropathy). Familial cases are distinct from sporadic cases. UTUCs belong to the HNPCC syndrome and they rank third in its tumor spectrum., Conclusion: UTUCs are scarce tumors with specific epidemiologic characteristics. UTUCs share common risk factors with other urothelial carcinomas such as bladder tumors but have also specific risk factors that clinicians should know., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Background: Tannery workers are at considerable risk of developing occupational contact dermatitis. Occupational skin diseases in tannery workers in newly industrialized countries have been reported, but neither the prevalence of occupational allergic contact dermatitis nor the skin-sensitizing agents were specifically examined in those studies., Objectives: To assess the prevalence of occupational allergic contact dermatitis in Indonesian tanneries, identify the causative allergens, and propose a tannery work series of patch test allergens., Patients/methods: A cross-sectional study in all workers at two Indonesian tanneries was performed to assess the prevalence of occupational contact dermatitis via a questionnaire-based interview and skin examination. Workers with occupational contact dermatitis were patch tested to identify the causative allergens., Results: Occupational contact dermatitis was suspected in 77 (16%) of the 472 workers. Thirteen (3%) of these 472 workers were confirmed to have occupational allergic contact dermatitis. Potassium dichromate (9.2%), N,N-diphenylguanidine (5.3%), benzidine (3.9%) and sodium metabisulfite (2.6%) were found to be the occupationally relevant sensitizers., Conclusions: The sensitization pattern showed some differences from the data in studies reported from other newly industrial countries. We compiled a 'tannery work series' of allergens for patch testing. A number of these allergens may also be considered for patch testing in patients with (leather) shoe dermatitis., (© 2012 John Wiley & Sons A/S.)

Background: A historical cohort study was conducted among 997 individuals employed at a chemical production facility to investigate whether occupational exposures to benzidine and other arylamines were associated with the increased risk of cancer., Methods: Cancers were identified from cancer registries, death certificates, and medical records. Exposures were evaluated using a job-exposure matrix. Workers were categorized into exposure groups to calculate cancer-specific standardized incidence ratios (SIRs) and perform survival analyses., Results: SIRs for cancer of the bladder (SIR = 3.5; CI 1.7, 6.4), small intestine (SIR 18.4; CI 2.2, 66.4), and soft tissue including heart (SIR = 11.9; CI 1.4, 42.8) were elevated among workers with the highest exposures and risk increased with increasing exposures. SIRs for several additional cancers were also elevated., Conclusion: Our results support previous findings of increased risk of bladder cancer among individuals exposed to benzidine and other arylamines. Workers may also have been at increased risk for cancers other than cancer of the bladder., (Copyright © 2011 Wiley-Liss, Inc.)

Most arylamines are pro-carcinogens, and require metabolic activation to yield ultimate carcinogen metabolites. O-Acetylation of the N-hydroxy form of an arylamine yields an acetoxyarylamine, which can form a highly reactive arylnitrenium ion, the ultimate metabolite responsible for DNA adduct formation. However, we demonstrate here that the N-hydroxy and nitroso forms of arylamines can also induce DNA damage, including 7,8-dihydro-8-oxo-2'-deoxyguanosine (8-oxodG) lesions, via reactive oxygen species formation. The N-hydroxy and nitroso derivatives of carcinogenic arylamines may contribute to the carcinogenic process through H2O2 formation. N-Hydroxy derivatives induce metal-mediated DNA damage, with remarkable enhancement by NADH. Nitroso derivatives induce NADH-dependent DNA damage in the presence of metal ions. Hydroxy derivatives of arylamines formed by enzymatic hydroxylation or as o- or p-aminophenols can also induce DNA damage in the presence of metal ions. The autoxidation of o-phenylenediamine and several arylamine metabolites is accelerated in the presence of SOD or manganese, resulting in the enhancement of metal-mediated DNA damage. The oxidative DNA damage induced by arylamine compounds may participate in chemical carcinogenesis, in addition to DNA adduct formation.

We estimated pollution in Lake Edku and the Mediterranean Sea, El-Maadiya Region, with 3 aromatic amines (1-naphthylamine, 2-naphthylamine and benzidine) in the muscle tissue of fish. There were marked seasonal variations in the aromatic amine levels. We also determined oxidative stress (blood glutathione, and catalase activity) and genotoxic effects (chromosomal aberrations and urinary metabolites) in fishermen from each area. The fishermen suffered from oxidative stress and had high levels of the urinary metabolite sulfanilamide [mean (microg/mg creatinine): Lake Edku 20.7, Mediterranean 14.5, controls 5.3]. Frequencies for total chromosomal aberrations were significantly raised in the peripheral blood lymphocytes of fishermen in both areas [frequency (per 100 metaphases): Mediterranean 67, Lake Edku 45, controls 14].

Presumptive blood detection tests are used by forensic investigators to detect trace amounts of blood or to investigate suspicious stains. Through the years, a number of articles have been published on the popular techniques of the day. However, there is no single paper that critiques and compares the five most common presumptive blood detection tests currently in use: luminol, phenolphthalein (Kastle-Meyer), leucomalachite green, Hemastix and the forensic light source. The present authors aimed to compare the above techniques with regard to their sensitivity, ease of use and safety. The luminol test was determined to be the most sensitive of the techniques, while Hemastix is a suitable alternative when the luminol test is not appropriate., (Copyright 2006 John Wiley & Sons, Ltd.)

N-acetyltransferase 1 (NAT1) modifies bladder cancer risk in European populations exposed to aromatic amines in cigarette smoke. The present study was performed to investigate a possible association between NAT1*10 and NAT1*14A genotypes and bladder cancer risk in benzidine-exposed Chinese workers. Based on the cytological gradings of exfoliated urothelial cells according to Papanicolaou, an exposed research cohort was stratified into subgroups. An allele-specific PCR-based procedure was used to detect the polymorphism in the polyadenylation signal at the locus NAT1 T(1088)A. A nested PCR-RFLP procedure was conducted to differentiate NAT1*14A (T(1088)A, C(1095)A, and G(560)A) from NAT1*10 (T(1088)A, C(1095)A). No significantly different frequencies of homozygous and heterozygous NAT1*10 alleles were found among the subgroups with (i) gradings according to Papanicolaou < or = II (18.3 and 40.2%, respectively), (ii) higher gradings according to Papanicolaou (> II; 28.0 and 34.1%, respectively), and (iii) with bladder cancer (26.3 and 34.2%, respectively). The present data show that NAT1*10 neither displayed an association with an elevated grading of urothelial cells nor a clear impact on the risk for bladder cancer in benzidine-exposed Chinese workers. Discrepancies with the findings in European populations could point to ethnic differences in the disposition of aromatic amines.

Occupational factors have been proposed to play a critical role in bladder cancer. This population-based case-control study was conducted to confirm the association between selected occupational and non-occupational risk factors and risk of bladder cancer using data collected from the four western Canadian provinces. Unconditional logistic regression analyses were based on 549 histologically confirmed bladder cancer cases and 1099 controls. Bladder cancer risk was found to increase with increasing pack-years of cigarette smoking with an odds ratio (OR) in the highest quartile of 3.32 (95% confidence interval [CI], 2.28-4.82). A dose-response relationship was demonstrated between bladder cancer and pack-years of smoking (p < 0.0001). A positive trend was observed with coffee consumption in men (p < 0.0001), with the highest risk in the highest category of exposure: drinkers of four cups or more per day had an OR of 1.77 (95% CI 1.11-2.82). Increased bladder cancer risk was associated with self-reported exposure at work to several chemicals: asbestos (OR 1.69 [95% CI 1.07-2.65]); mineral, cutting or lubricating oil (1.64 [95% CI 1.06-2.55]); benzidine (2.20 [95% CI 1.00-4.87]). The population attributable fraction (PAF) estimates were 51% for cigarette smoking, 17% for heavy coffee consumption, 10% for mineral, cutting or lubricating oil exposure, 6% for asbestos exposure, and 1% for benzidine exposure. Although self-reported chemical exposures have important limitations, the findings are suggestive of increased risk for several associations previously reported between chemical agents or industries and risk of bladder cancer.

Objective: Glutathione S-transferases are involved in the conjugation of xenobiotics. To explore whether GSTs polymorphisms are involved in the development of occupational or non-occupational bladder cancer, polymorphism frequencies of GSTT1, M1 and P1 were investigated in a normal population, which had been settled in a rural area in Shanghai suburb for at least 5 generations as well as in a group of patients with benzidine exposure related occupational bladder cancer in Shanghai dyestuff industry and a group of patients with non-occupational bladder cancer., Methods: PCR based procedures were performed in the study populations to confirm the genotypes of GSTT1, M1 and P1., Results: The polymorphisms at locus of GSTP1-A1578G in the normal population differed significantly from those in Caucasians or African Americans. All the subjects genotyped so far (n = 118) bore only homogenous wild genotype (C2293/C2293) at GSTP1-C2293T locus. This locus seemed to be a monomorphic in Shanghai population. No significant difference in GSTT1 and GSTM1 polymorphic form frequencies could be confirmed among three groups of subjects. An overrepresentation of GSTP1 AG or GG genotype corresponding a less stable and less effective isozyme protein was detected in patients with benzidine related occupational bladder cancer, compared with that in the normal population though a statistical significance was not yet reached (P = 0.09, OR = 1.96, 95% CI 0.89-4.32)., Conclusion: This study suggests that GSTM1 or GSTT1 homozygous deficiency genotypes and their combination do not have a clear impact on bladder cancer incidence in a Shanghai population. It seems that GSTP1 polymorphism is not associated with non-occupational bladder cancer. GSTP1 AG or GG genotype has a higher frequency in the patients with benzidine related occupational bladder cancer, and further work is needed to confirm if GSTP1 AG or GG genotype plays a role in the development of occupational bladder cancer.

A multiple biomarker approach is required to integrate for metabolism, temporal response and exposure-response kinetics, biological relevance, and positive predictive value. Carcinogen DNA adduct analysis can be used in animal and in vitro studies to detect absorption permutations caused by mixture interactions, and to control metabolic variation when specific CYP450 genes (1A1 or 1A2) are knocked out. These enzymes are not critical to the metabolic activation of model Polycyclic Aromatic Compounds (PAC) and aromatic amines, respectively, as suggested by in vitro analysis. Several human studies have been carried out where multiple biomarkers have been measured. In a study of benzidine workers, the similarities in elimination kinetics between urinary metabolites and mutagenicity is likely responsible for a better correlation between these markers than to BZ-DNA adducts in exfoliated cells. In a study of rubber workers, the relationship between specific departments, urinary 1 HP and DNA adducts in exfoliated cells coincided with the historical urinary bladder cancer risk in these departments; the same relationship did not hold for urinary mutagenicity. In a study of automotive mechanics, biomarkers were used to monitor the effectiveness of exposure interventions. These data reinforce the notion that carcinogen biomarkers are useful to monitor exposure, but that a complementary approaches involving effect and perhaps susceptibility biomarkers is necessary to obtain the necessary information.

Aim: To assess two polymorphic forms of aryl hydrocarbon receptor (AHR) gene, G1721A (R554K), and G1768A (V570I) in Chinese population and to explore the possible association of human AHR gene polymorphism with elevated incidence of bladder cancer among Chinese Han subjects in east of China., Methods: An allele specific PCR-based procedure for AHR gene polymorphism genotyping was developed by this work. Genotyping on three groups of subjects in Shanghai area had been performed: a bladder cancer group with the occupational exposure to benzidine, a non-occupational bladder cancer patient group whose members lack an obvious aromatic amine exposure record, and a normal population in the same city as controls., Results: A significant difference (P < 0.01) in frequency distribution at locus G1721A between normal population in Shanghai and a Caucasian population reported by other authors was observed. No mutant allele(A1768) at locus G1768A had ever been detected in our study. The observed frequencies were similar between both genders in the normal population (P = 0.54), and there were no significant difference confirmed between the case group and the control group., Conclusion: The locus G1768 of human AHR gene seems to be monomorphic among Chinese in this area. The significant distribution difference at locus G1721A of human AHR gene between Chinese Han and Caucasian was confirmed. This study did not support the association of AHR G1721A polymorphism with higher risk to bladder cancer among the residents in this area, either in a group of occupationally benzidine-exposed individuals or among the persons who never have an obvious aromatic amine exposure record.

Background: The carcinogenesis of benzidine (BZ) and beta-naphthylamine (BNA) for bladder is well known. Although it was thought to be rare to develop occupational bladder cancer more than 20 years after the exposure to these chemicals, there are still new clinical cases even 30 years after exposure. The purpose of this study was to re-evaluate the latent carcinogenic period of BZ and BNA, in order to set the safety period after exposure for the health surveillance system., Methods: The subjects were 236 dyestuff-plant workers in Tokyo, who had been exposed to these dyestuffs. The incidence of bladder cancer and its histopathology in this group was surveyed in the period from 1962 to 1996., Results: Nineteen workers (8.1%) were found to have bladder cancers. The exposure period for these 19 patients was 82.0 +/- 50.2 months. The mean +/- SD latent period from the subjects' initial and final exposure until tumor development was 29.5 +/- 8.2 years and 20.1 +/- 10.6 years, respectively. Significantly, a negative correlation (Pearson) was observed between the exposure period and the latent period from the end of exposure to cancer onset (R = -0.544, P < 0.05). All tumors except one were transitional cell carcinoma. Flow cytometric analysis was performed in 11 patients and all of these patients had DNA aneuploidy., Conclusions: The latent periods of bladder cancer caused by BZ and BNA were longer than previously expected. It is necessary to survey the onset of bladder cancer in exposed workers more than 30 years after the initial exposure.

Background: Cancer screening with highly sensitive, specific biomarkers that reflect molecular phenotypic alterations is an attractive strategy for cancer control. We examined whether biomarker profiles could be used for risk assessment and cancer detection in a cohort of Chinese workers occupationally exposed to benzidine and at risk for bladder cancer., Methods: The cohort consisted of 1788 exposed and 373 nonexposed workers, followed from 1991 through 1997. We assayed urothelial cells from voided urine samples for DNA ploidy (expressed as the 5C-exceeding rate [DNA 5CER]), the bladder tumor-associated antigen p300, and a cytoskeletal protein (G-actin). Workers were stratified into different risk groups (high, moderate, and low risk) at each examination based on a predefined biomarker profile. For workers who developed bladder cancer, tumor risk assessment was analyzed from samples collected 6-12 months before the cancer diagnosis. The associations between risk group and subsequent development of bladder cancer were analyzed by Cox proportional hazards regression analysis and logistic analysis, after adjustment. All statistical tests were two-sided., Results: Twenty-eight bladder cancers were diagnosed in exposed workers and two in nonexposed workers. For risk assessment, DNA 5CER had 87.5% sensitivity, 86.5% specificity, an odds ratio (OR) of 46.2 (95% confidence interval [CI] = 8.1 to 867.0), and a risk ratio (RR) of 16.2 (95% CI = 7.1 to 37.0); p300 had 50.0% sensitivity, 97.9% specificity, an OR of 40.0 (95% CI = 9.0 to 177.8), and an RR of 37.9 (95% CI = 16.8 to 85.3). The risk of developing bladder cancer was 19.6 (95% CI = 8.0 to 47.9) times higher in workers positive for either the DNA 5CER or p300 biomarkers than in workers negative for both biomarkers and 81.4 (95% CI = 33.3 to 199.3) times higher in workers positive for both biomarkers. G-actin was a poor marker of individual risk., Conclusions: Occupationally exposed workers at risk for bladder cancer can be individually stratified, screened, monitored, and diagnosed based on predefined molecular biomarker profiles.

Economical, social and technical interrelations between synthetic dyes' production and bladder cancer in workmen engaged in the manufacture are reviewed. International situation is the background of Italian situation, mainly of the Lombardy region and Turin area. For decades social actors, individuals and institutions, acted as separate bodies, contributed to delay and omit the protection of workers' health. The situation changed when scientific knowledge, technical developments and workers' commitment prioritized workers' health as a main goal. The epidemic of bladder cancers among dyestuff workers was a cornerstone in the development of a different scenario in the production responsibility, workers' participation and eventually scientific community. The authors hypothesise that in our country these events stimulated the growth of epidemiology and epidemiologists; furthermore since then institutions promulgated a new and up-to-date wave of protective legislation in the workers' H&S field.

Workers exposed to high levels of benzidine have a 100-fold increased incidence of bladder cancer. This review evaluates the overall metabolism of benzidine to determine pathways important to initiation of bladder cancer. Upon incubation of benzidine with liver slices from rats, dogs, and humans, different proportions of this diamine were N-acetylated and N-glucuronidated. With dogs, a non-acetylator species, N-glucuronidation was the major pathway. In contrast, little glucuronidation was observed in rats with N, N'-diacetylbenzidine, the major metabolite of benzidine. Human liver slices demonstrated both extensive N-acetylation and N-glucuronidation. Differences between rats and humans were attributed to rapid deacetylation by human liver with N-acetylbenzidine rather than an accumulation of N, N'-diacetylbenzidine. N-Acetylbenzidine oxidative metabolism was also observed. The acid lability of glucuronide products of benzidine, N-acetylbenzidine, and oxidation products of N-acetylbenzidine metabolism was assessed. N-Glucuronides of benzidine, N-acetylbenzidine, and N'-hydroxy-N-acetylbenzidine were acid-labile, with the latter having a much longer half-time than the former two glucuronides. Because bladder epithelium contains relatively high levels of prostaglandin H synthase and not cytochrome P450, the peroxidative metabolism of N-acetylbenzidine was assessed. N'-(3'-Monophospho-deoxyguanosin-8-yl)-N-acetylbenzidine was the only DNA adduct detected. This adduct is also the major adduct detected in bladder cells from workers exposed to benzidine. In urine from these workers, an inverse relationship between urine pH and levels of free (unconjugated) benzidine and N-acetylbenzidine was observed. A similar inverse relationship was observed for urine pH and levels of bladder cell N'-(3'-monophospho-deoxyguanosin-8-yl)-N-acetylbenzidine. These results suggest multiple pathways (acetylation, glucuronidation, peroxidation) in multiple organs (liver, blood, kidney, bladder) are important in benzidine-induced bladder cancer.

Purpose: It is speculated that the susceptibility to urothelial cancer in dye workers who are exposed to aromatic amines is affected not only by occupational environmental factors but by host specific factors. We evaluated the interaction between glutathione S-transferase M1 gene deficiency and the occupational environmental factors associated with urothelial cancer., Materials and Methods: The study included 137 workers who had prior exposure to dyestuff intermediates, of whom 36 had urothelial cancer. The prevalence of a glutathione S-transferase M1 gene polymorphism was investigated using polymerase chain reaction. The relationship between the glutathione S-transferase M1 0/0 gene and occupational environmental factors in the onset of urothelial cancer was examined by multivariate analysis., Results: The prevalence of glutathione S-transferase M1 gene deficiency did not differ significantly between the urothelial cancer (21 cases, 58.3%) group and the cancer-free (47, 46.3%) group. It was estimated that 29.6% of the urothelial cancers in these dye workers was attributable to the glutathione S-transferase M1 0/0 gene. Analysis using multiple logistic models showed low predictive ability for urothelial cancer due to glutathione S-transferase M1 gene deficiency (p = 0.084, odds ratio 2.260, 95% confidence interval [CI] 0.904 to 5.652). A history of working in small factories (p = 0.000, odds ratio 7.404, 95% CI 2.854 to 19.206) and a long period of exposure (p = 0.016, odds ratio 5.051, 95% CI 1.371 to 18.612) significantly predicted cancer., Conclusions: We demonstrated a strong trend using the multiple logistic analysis of the contribution of glutathione S-transferase M1 gene polymorphism and occupational environmental factors. Therefore, the glutathione S-transferase M1 enzyme might have an important role in the detoxification of aromatic amine derived carcinogens. Occupational environmental factors, however, might contribute more than a glutathione S-transferase M1 gene deficiency to the occurrence of urothelial cancer among individuals exposed to aromatic amines, because of the extremely potent carcinogenicity of some occupational environmental factors.

In a cross-sectional study of 33 workers exposed to benzidine and benzidine dyes and 15 non-exposed controls, we previously reported that exposure status and internal dose of benzidine metabolites were strongly correlated with the levels of specific benzidine-DNA adducts in exfoliated urothelial cells. We also evaluated DNA adduct levels in peripheral white blood cells (WBC) of a subset of 18 exposed workers and 7 controls selected to represent a wide range of adducts in exfoliated urothelial cells. Samples were coded and then DNA was analyzed using 32P-postlabeling, along with n-butanol extraction. One adduct, which co-chromatographed with a synthetic N-(3'-phospho-deoxyguanosin-8-yl)-N'-acetylbenzidine standard, predominated in those samples with adducts present. The median level (range) of this adduct in WBC DNA was 194.4 (3.2-975) RAL x 10(9) in exposed workers and 1.4 (0.1-6.4) in the control subjects (p = 0.0002, Wilcoxon Rank Sum Test). There was a striking correlation between WBC and exfoliated urothelial cell adduct levels (Pearson r = 0.84, p < 0.001) among exposed subjects. In addition, the sum of urinary benzidine, N-acetylbenzidine and N,N'-diacetylbenzidine correlated with the levels of this adduct in both tissues. This is the first study in humans to show a relationship for a specific carcinogen adduct in a surrogate tissue and in urothelial cells, the target for urinary bladder cancer.

Objectives: To evaluate the mortality of a group of tannery workers., Methods: The cohort consisted of 1244 workers (870 men and 374 women) employed at a chrome tannery between 1955 and 1988. A total of 36414 person-years of follow up was calculated (369 people had died). National and regional mortalities were used to estimate the expected numbers., Results: All cause mortality was similar to that of the general population. The most remarkable excess was for bladder cancer (observed 10, standardised mortality ratio (SMR) 242, 95% confidence interval (95% CI) 116 to 446). An excess of colorectal cancer (observed 17, SMR 180, 95% CI 105 to 288) was also found, based on an increased risk of both colon (SMR 166) and rectal cancer (SMR 206). No recognisable patterns emerged from the analyses by years since first employment, calendar year of hire, or lagging exposures., Conclusions: The increased mortality from bladder cancer is likely due to exposure to benzidine based leather dyes. If the apparent excess of colorectal cancer is real, its causes are as yet unknown.

Epidemiological evidence on the relation between aromatic amines and cancer risk is reviewed. In particular, cancer risk in humans resulting from exposure to aromatic amines from occupational sources and tobacco smoking is assessed with reference to ecologic, cohort, and case-control studies. Seven arylamines have been classified by the International Agency for Research on Cancer: benzidine-based dyes and MOCA (4,4'-methylene bis 2-choloroaniline) were considered 'probably' carcinogenic, Group 2A, because of a high level of evidence in experimental animals; two occupational chemicals (2-naphthylamine and benzidine), one drug (Chlornaphazine), and two manufacturing processes (manufacture of auramine and magenta) were included in Group 1 on the basis of 'sufficient' evidence of carcinogenicity in humans. Occupational exposures to aromatic amines explain up to 25 percent of bladder cancers in some areas of Western countries; these estimates might be higher in limited areas of developing countries. Aromatic amines contaminate the ambient air as a component of environmental tobacco smoke. There is increasing evidence that the excess of bladder cancer in smokers is attributable to aromatic amines rather than to other contaminants of tobacco smoke such as polycyclic aromatic hydrocarbons (PAH). A modulating role in the risk of bladder cancer associated with exposure to aromatic amines is played by metabolic polymorphisms, such as the N-acetyltransferase genotype, raising important social and ethical issues. The consistent observation of a difference between men and women in bladder cancer risk, after allowing for known risk factors, suggests consideration of gender-related biological determinants for future investigation.

A case of triple primary cancers (renal cell carcinoma of the kidney, transitional cell carcinoma of the bladder, and hepatocellular carcinoma of the liver) was reported at autopsy. A 53-year-old man, who had a history of exposure to benzidine, underwent nephrectomy for a left renal cell carcinoma and 10 years later, transurethral resection of bladder tumor (TUR-Bt) for a transitional cell carcinoma of the bladder. At the age of 65, he was diagnosed as having multiple hepatic tumors. Histological examination of biopsy specimens showed these lesions to be undifferentiated carcinomas. Immunohistological examination of both biopsy and autopsy specimens revealed that multiple hepatic tumors were hepatocellular carcinomas, not metastatic tumors from kidney or urinary bladder: tumor cells of hepatic tumors were positive for alpha-fetoprotein, although renal cell carcinomas and transitional cell carcinomas of urinary bladder were positive for Ber-EP4 and keratin, respectively. These findings suggest not only that immunohistological examination is helpful for the diagnosis of multiple primary cancers but also that benzidine may be hepatocarcinogenic in addition to those cancers that are known to be associated with benzidine exposure, i.e., renal cell carcinomas and transitional cell carcinomas in urinary bladder.

We studied 438 persons who were engaged in the production and use of aromatic amines (benzidine sulfate, beta-naphthylamine, alpha-naphthylamine and dianisidine). Among these 438 persons, 88 new cases of occupational uroepithelial cancer had occurred from 1949 to 1995. The incident rate of occupational uroepithelial cancer was 20.1%. The average exposure period of these 88 cases to the aromatic amines was 7.40 years (range, 0.75-26.75), and the incidence rate of tumors increased with the length of exposure to aromatic amines. The average latent period was 26.79 years (range, 1.33-48.50), and the average age of first onset was 52.59 (range, 24-79). Recently it has been determined that the longer the latent period, the older the age of first onset. Of these 88 cases, the tumor sites were bladder in 67 cases (76.1%) and upper urinary tract (renal pelvis and/or ureter) in 5 cases (5.7%). The other 16 cases (18.2%) were the bladder and upper urinary tract. The screening examination for chemical workers using urinary cytology was begun in 1962. In our cases, urine cytology was a useful method for diagnosing occupational uroepithelial cancer. As for initial treatment of the 88 cases, transurethral surgery was most frequently performed, that is on 58 cases (65.9%). However, eight cases (9.1%) had to undergo a total nephroureterectomy, and six cases (6.8%) had a total cystectomy. Recurrence was observed in 61 cases (69.3%) out of the 88 patients with an average of 1.81 times. The other organic cancers developed in 39 cases (8.9%) out of 438 workers who were exposed to aromatic amines and in 8 cases out of 88 patients (9.1%). Prognosis of the 88 patients is that, the number of alive and dead is 51 (58.0%) and 37 (42.0%) respectively on December 31, 1995. Twenty-eight patients (31.8%) died of uroepithelial cancer, and five patients (5.7%) died of other organic cancers. The survival rates of 5, 10, 15 and 20 years was 87.9%, 74.0%, 65.9% and 56.3%, respectively. From these results, patients with occupational uroepithelial cancer and workers who are exposed to aromatic amines should undergo long term observation.

Multiple studies in the general population have suggested that subjects with the glutathione S-transferase M1 (GSTM1)-null genotype, who lack functional GSTM1, are at higher risk for bladder cancer. To evaluate the impact of the GSTM1-null genotype on bladder cancer caused by occupational exposure to benzidine and to determine its influence on benzidine metabolism, we carried out three complementary investigations: a case-control study of bladder cancer among workers previously exposed to benzidine in China, a cross-sectional study of urothelial cell DNA adducts and urinary mutagenicity in workers currently exposed to benzidine in India, and a laboratory study of the ability of human GSTM1 to conjugate benzidine and its known metabolites in vitro. There was no overall increase in bladder cancer risk for the GSTM1-null genotype among 38 bladder cancer cases and 43 controls (odds ratio, 1.0; 95% confidence interval, 0.4-2.7), although there was some indication that highly exposed workers with the GSTM1-null genotype were at greater risk of bladder cancer compared to similarly exposed workers without this allele. However, the GSTM1 genotype had no impact on urothelial cell DNA adduct and urinary mutagenicity levels in workers currently exposed to benzidine. Furthermore, human GSTM1 did not conjugate benzidine or its metabolites. These results led us to conclude that the GSTM1-null genotype does not have an impact on bladder cancer caused by benzidine, providing a contrast to its association with elevated bladder cancer risk in the general population.

We have analyzed the bladder biopsies of six bladder cancer patients exposed to high levels of 2-naphthylamine and benzidine, 11 unexposed bladder cancer patients, six subjects with benign conditions of the bladder, and 16 healthy subjects. Immunohistochemical analysis of the p21 and p185 protein products, for overexpression of ras and c-erbB-2 oncogenes, was performed. Overexpression of ras was found in four of six exposed cancer patients, 3 of 11 unexposed cancer patients, zero of six benign disease patients, and zero of 16 healthy subjects. The odds ratio for ras overexpression, comparing exposed with unexposed cases, was 5.3 (90% confidence interval 0.6 to 64). Overexpression of c-erB-2 was apparently not associated with occupational exposure.

Previously, we found a decrease in CD4 + CD45RA + T lymphocytes in workers exposed to the aromatic amines (AAs) [benzidine (BZ) and beta naphthylamine (BNA)]. For further investigation of the effects of AAs on lymphocyte subpopulations, we measured natural killer (NK) cell subpopulations using two-color staining with anti-Leu7 (CD57) and anti-Leu11 (CD16) monoclonal antibodies in peripheral blood in 78 male dyestuff workers. The workers had been exposed to AAs before 1972 at a chemical plant, either in the production of AAs (40 workers, high-exposure group) or in other work that involved handling dyestuffs (38 workers, low-exposure group). The controls were 30 "healthy" male volunteers without a history of occupational exposure to AAs or hazardous chemicals. The number of CD57 + CD16- cells in the high-exposure group was significantly higher than that in the controls (P < 0.01, analysis of covariance with age as a covariate). No significant differences were found in CD57 + CD16-, CD57 + CD16+ and CD57- CD16 + NK cells between the low-exposure group and the controls. It is suggested that a decrease in the number of CD4+ T lymphocytes following exposure to AAs might be compensated by the increase in CD57 + CD16- cells, i.e. circulating peripheral lymphocytes with poor NK cell activity.

Benzidine, an odorless, white to slightly reddish-white crystalline organic compound, is an environmental contaminant that has been identified at about 30 National Priorities List (NPL) hazardous waste sites in the United States. In the environment, it is usually found attached to suspended particles either in its "free" state or as chloride or sulfate salts. In the past, U.S. industries used large quantities of benzidine to produce dyes for paper, clothes, and leather. Since the ban on its production and use in the United States in the 1970s, this compound is imported for specialty uses. People living near hazardous waste sites might be exposed to benzidine by drinking contaminated water, by inhaling contaminated air, or by swallowing or touching contaminated dust. People can also be exposed by using benzidine dyes on paper, clothes, and other materials. Human occupational data and studies of laboratory animals suggest that people exposed to benzidine may develop adverse systemic health effects or cancer. The U.S. Environmental Protection Agency (EPA), the U.S. Department of Health and Human Services, the International Agency for Research on Cancer (IARC), and the World Health Organization (WHO) have classified benzidine as a carcinogen. Urinary bladder cancer is the most common form of cancer caused by exposure to benzidine. The stomach, kidneys, brain, mouth, esophagus, liver, and gallbladder might also be targets. The information presented in the article may help public health officials, physicians, and toxicologists evaluate and develop the health information materials on the nature of benzidine in the environment and its potential impact on public health.

Background: Although the occupational exposure to some aromatic amines is recognized to cause bladder carcinoma, the long term effect of such exposure on the risk for disease, including other malignant tumors, remains unknown., Methods: A total of 442 dyestuff workers exposed to one or more substances including benzidine (BZ), beta-naphthylamine (beta-N), alpha-naphthylamine (alpha-N), and dianisidine were followed completely until December 1992 (average time since first exposure, 39.4 years). Besides the underlying cause of death, the incidence of urothelial carcinoma was determined by periodic urologic screenings., Results: Analyses of site-specific cancer mortality revealed a remarkable increased risk for bladder carcinoma for those engaged in BZ manufacture (standardized mortality ratio [SMR] = 63.6), BZ use (SMR = 27.0) and beta N manufacture (SMR = 48.4), but not for those who were exposed to alpha-N. The increased risk of cancer mortality for other organs was not significant for any exposure classes. The crude incidence rate per 1000 person-years of bladder carcinoma was estimated to be 8.7 for those engaged in BZ manufacture, 2.9 in BZ use, 7.7 in beta-N manufacture and 1.0 in beta-N use. Regardless of the class or type of exposure, the adjusted incidence rate of urothelial carcinoma increased with the duration of exposure. The adjusted incidence rate for BZ manufacture remained high (3.8-12.8) during the entire observation period, whereas that for BZ use increased from 0.0 to 4.4 as the time since first exposure increased from less than 10 years to 30+ years., Conclusions: Occupational exposure to either BZ or beta-N demonstrated an extremely strong and prolonged effect on workers' risk for urothelial carcinoma, particularly for bladder carcinoma, but not for malignant neoplasms of other organs.

Background: Cancer incidence and mortality were evaluated among 4581 aniline dye production workers in Moscow., Methods: A historical cohort was assembled and followed-up from 1 January 1975 to 31 December 1989. Moscow district oncologic dispensary registries furnished case ascertainment and employer records provided job exposure data. Expected cancers and deaths were calculated based on gender-, age-, and calendar time-specific incidence and mortality rates for the Moscow general population applied to the cohort's person-years of follow-up. Disease-specific standardized mortality and incidence values were derived from ratios of observed to expected cancers., Results: Men experienced elevated total cancer mortality (standardized mortality ratio [SMR] = 125; 95% CI: 110-142) and urinary bladder cancer mortality (SMR = 279; 95% CI: 192-391), and increased all malignancy (standardized incidence ratio [SIR] = 142; 95% CI: 125-160), oesophageal (SIR = 203; 95% CI: 108-347), respiratory tract (SIR = 154; 95% CI: 120-194) and bladder (SIR = 394; 95% CI: 268-559) cancer incidence. Women had elevated oesophageal (SMR = 313; 95% CI: 124-664) and bladder (SMR = 311; 95% CI: 149-571) cancer mortality and elevated all malignancy (SIR = 124; 95% CI: 106-144), oesophageal (SIR = 348; 95% CI: 140-719), and bladder (SIR = 861; 95% CI: 458-8002) cancer incidence. Bladder cancer rate increased with employment duration and younger age first hired. Rate estimates were highest among beta-naphthylamine exposed workers but was also increased among workers with other chemical exposures. A cancer prevention and control effort that limited benzidine exposure to < or = 3 years was apparently unsuccessful as indicated by a significant excess of bladder cancer (SIR = 1773; 95% CI: 356-5180) among these workers., Conclusion: Relative rates of oesophageal, lung, and stomach cancer were also elevated among all workers, but did not increase with total years worked, age first hired, or year first hired, suggesting a non-occupational aetiology.

Occupational exposure to arylamines such as benzidine, 2-naphthylamine, and 4-aminobiphenyl is associated with exceptionally elevated risks of bladder cancer (up to 100-fold or more). In one plant, all 15 workers involved in distilling naphthylamine developed bladder cancer, suggesting that for high levels of exposure to potent carcinogens individual susceptibility is irrelevant. More recently, exposure to other arylamines also has been suggested to increase the risk of bladder cancer in humans. In addition, cohort and case-control studies suggest that several job titles or exposures may involve elevated risks of bladder cancer. Some of these jobs or exposures (such as in the aluminum industry) are associated with exposure to arylamines. Arylamines are found also in tobacco smoke, and different sources of evidence suggest that they can explain the risk of bladder cancer, which has been shown clearly in smokers. Epidemiologic analyses of timing of exposure in workers occupationally exposed to arylamines or in air-cured tobacco smokers suggest that arylamines exert both an early- and a late-stage activity, compatible with a two-mutation theory of bladder carcinogenesis.

T lymphocyte subpopulations (CD4+, CD8+, and CD3+ cells), Leu 11a-(CD16) positive lymphocytes, and total lymphocytes in peripheral blood in 52 male dyestuff workers were analyzed to determine the effects of benzidine and beta-naphthylamine on the human immune system. The workers had been exposed prior to 1972 to benzidine and beta-naphthylamine (aromatic amines) at a chemical plant. The dyestuff workers included 27 workers who had engaged in production of aromatic amines (i.e., high-exposure group) and 25 workers who had handled dyestuff at their job (low-exposure group). The total and relative numbers of CD4+ and CD3+ T lymphocytes in the high-exposure group were significantly lower than those found in the control (no-exposure) group (p < .01). Relative--but not total--number of CD16+ lymphocytes in the high-exposure group was significantly higher than in the control group (p < .05). However, there were no significant differences between the low-exposure group and control group with respect to all T lymphocyte subpopulations, CD16+, and total lymphocytes. Perhaps the number of circulating CD4+ T lymphocytes decreases in workers exposed to aromatic amines. It is concluded that measurement of CD4+ lymphocytes provides a useful biological marker of past exposure to aromatic amines.

Several studies in subjects occupationally exposed to arylamine carcinogens have shown increased risks for bladder cancer associated with the slow acetylator phenotype. To follow up these reports, a case-control study of N-acetylation and bladder cancer risk was carried out among subjects occupationally exposed to benzidine, in benzidine dye production and use facilities in China. Thirty-eight bladder cancer cases and 43 controls from these factories were included for study of acetylation phenotype, by dapsone administration, and for polymorphisms in the NAT2 gene, by a polymerase chain reaction (PCR)-based test. In contrast to previous studies, no increase in bladder cancer risk was found for the slow N-acetylation phenotype (OR = 0.3; 95% CI = 0.1-1.3) or for slow N-acetylation-associated double mutations in NAT2 (OR = 0.5; 95% CI = 0.1-1.8). Examination of specific mutations and adjustment for age, weight, city and tobacco use did not alter the results. When examined by level of benzidine exposure in the cases, the bladder cancer risks associated with low (OR = 0.3, 95% CI = 0.0-2.2), medium (OR = 0.7, 95% CI = 0.1-4.5) and high (OR = 0.6, 95% CI = 0.1-3.5) exposure showed no interaction between genotype and benzidine exposure, within the range of exposures experienced by subjects in this study. This study, which is the first to incorporate phenotypic and genotypic analyses, provides evidence that the NAT2-related slow N-acetylation polymorphism is not associated with an increased risk of bladder cancer in workers exposed to benzidine, and may have a protective effect.

Modern molecular and cellular biology have provided powerful new approaches to study cancer in the research laboratory, but these techniques have not been used extensively in field studies or in screening of high-risk occupational cohorts. The primary objective of this study was to demonstrate the use of cellular and molecular methods in combination with medical and epidemiologic methods to identify cancer cases, risk factors, and markers in a previously identified and defined cohort of Chinese workers exposed to benzidine. The screening of exposed workers included occupational, medical, and smoking histories to identify exogenous risk factors, a limited physical examination, Papanicolaou (PAP) urinary cytology, measurement of urine pH, quantitative fluorescence image analysis (QFIA) cytology to detect DNA hyperploidy, and quantitative fluorescence to detect expression of a low-grade bladder tumor-associated antigen (p300) by exfoliated urothelial cells and elevated expression of the neu oncogene product (p185). Detailed analysis of the accuracy of epidemiologic data and the adequacy of samples and accuracy of molecular techniques was carried out. Three groups were included in this study: group 1 included 23 bladder cancer cases who had previously been exposed to benzidine and served as two surrogates for late-emerging disease; group 2 consisted of 20 subjects with previous exposure history but not previously diagnosed with bladder cancer; and group 0 was the nonexposure and nonbladder cancer controls. The results showed that accurate questionnaire data and urine samples can be obtained at remote sites. Among the 20 group 2 subjects, two displayed abnormal findings by both QFIA cytology and p300 expression and were later confirmed to have bladder cancer.(ABSTRACT TRUNCATED AT 250 WORDS)

Epidemiologic studies of occupational groups have been central to the identification of human carcinogens. The incorporation of a biochemical component into occupational studies of cancer can expand the possibilities for identifying human carcinogens and for understanding the disease process. Two epidemiologic studies of occupation and cancer which include evaluation of biomarkers are described. The association of acetylator phenotype with bladder cancer risk was studied in benzidine-exposed workers. The association of benzene-related leukopenia with leukemia is being studied in benzene-exposed workers. These investigations illustrate issues in the use of biomarkers in epidemiologic studies of cancer risk. Such studies require the identification and characterization of the population at risk. Disease susceptibility factors are amenable for inclusion in these studies and can be statistically modeled as exposure-effect modifiers. Biomarkers of exposure are mainly of importance in short-term longitudinal and cross-sectional studies of exposure and intermediate outcomes and for validation of other data sources. Several sources of error can affect the results of molecular epidemiologic studies. Aside from minimizing laboratory error, consideration must be given in the design and execution of these studies to potential problems in subject selection and field collection of biologic samples and other relevant data.

We examined bladder cancer mortality and incidence to 1981 in 1,972 workers employed in benzidine-exposed jobs in Tianjin, Shanghai, and Jilin, China, between 1972 and 1977, and in 1,974 unexposed workers employed during the same time period. In comparison to general population rates, in the benzidine-exposed group the ratio of observed to expected deaths (SMR) was 17.5 (95% C.I.: 7.5-34.5) and the ratio of observed to expected incident cases (SIR) was 25.0 (95% C.I.: 16.9-35.7). No excess was noted in the unexposed group. The 25-fold increase in bladder cancer incidence in the exposed group was related to level of exposure, with the SIR rising from 4.8 for low exposure to 36.2 for medium exposure, and 158.4 for high exposure. Risks were elevated both for producers of benzidine (SIR = 45.7; 95% C.I.: 20.9-86.8) and for users (SIR = 20.9; 95% C.I.: 12.9-32.0) of benzidine dyes. Benzidine-exposed workers who smoked tobacco had a 31-fold risk (95% C.I.: 20.4-46.4), while non-smoking workers had an 11-fold risk (95% C.I.: 3.6-25.8), suggestive of a multiplicative relationship between these two carcinogens.

Between January 1951 and December 31, 1990 urothelial tumors were detected in 112 of 1,085 male dye workers (10.3%) in Wakayama City who were formerly engaged in manufacturing of benzidine and/or beta-naphthylamine. The period from exposure to the chemicals to development of the tumor was a mean of 24.1 +/- 9.4 years. A peak incidence of urothelial tumors was observed also approximately 25 years after the peak period of manufacturing these intermediate products of dyes. The mean period from exposure to such carcinogenic chemicals to the onset of the disease was estimated to be 25 years. Of the 78 patients with primary bladder cancer diagnosed since 1969, 43 (55.1%) had tumors diagnosed mostly as a result of a positive urinary cytology test obtained as part of a screening program and 35 (44.9%) had tumors diagnosed as the result of symptoms. Ten patients (24.4%) in the screened group had been treated with total cystectomy by the last followup examination compared with 17 (50.0%) in the symptomatic group. The 10-year cumulative survival rates were significantly (p less than 0.05) higher in the screened patients (75.1%) than in the symptomatic patients (55.1%). Our results indicate that screening of high risk populations with urinary cytology tests is effective for early diagnosis and treatment of urothelial tumors, and it improves patient prognosis. Furthermore, the biological behavior of occupational urothelial tumors may be different from that of urothelial tumors in the general population.

The epidemiology of bladder tumors was examined among the subjects exposed to cancerogenic amino compounds such as beta-naphthylamine and benzidine (Group 1). The workers from other chemical shops of the plant were enrolled as a control group (Group 2); those from service shops (Group 3) and white-collar ones (Group 4) were also included. A total examined group comprised 4,624 subjects followed up in 1975-1979. The age- and sex-adjusted bladder tumor morbidity rates in males were 48.3, 11.0, 6.9 in Groups 1, 2, and 3, respectively (the normal rate, 5.6 per 100,000), while the respective figures in females were 75.0 and 18.2 in Groups 1 and 2, respectively (the normal rate, 1.1 per 100,000). No bladder cancer was recorded among the male workers from service shops and female service and white-collar workers (the expected rate was less than 1). Calculating the bladder cancer morbidity rates by the common standard indices indicated that there was no excess of the rates typical of the disease for males as compared to females, which is generally observed on exposure to potent cancerogenic substances. There was an increase in the latent period of urinary bladder cancer progression from 13.0 to 18.6 in males and to 20.4 in females who had been exposed to benzidine, as compared to the 1950s and 1960s. The mean latent period was 24.2 years in females and 21.5 in males who had been exposed to beta-naphthylamine. 42% of all those who had diagnosed bladder cancer had not come in direct contact with the above cancerogenic agents.(ABSTRACT TRUNCATED AT 250 WORDS)

Epidemiology of cancer was studied in a group of aniline-dye industry workers. Cancer morbidity in those directly exposed to betanaphthylamine and benzidine was 1.8 and 2 times the expected one for males and females, respectively (p less than 0.05). Bladder cancer morbidity was many times the expected one for both males and females; it did not involve prevalence in male morbidity generally observed for this site. Primary multiple malignant tumors were more frequently registered in females. Stomach and lung cancer morbidity was increased in males (p less than 0.05). Also, prophylactic measures should be taken at factories using amino compounds which are suspected to be carcinogenic for man.

901 male workers who have ever been exposed to the benzidine-derived dyes for more than 1 year in Shanghai leather-tanning industry, were investigated about their occupational history, smoking and drinking histories, case history of cancer, and the causes of death. The results showed that there was an excess morbidity of bladder cancer in this population, and the SIR was 273 (P = 0.05) compared with the general population of Shanghai urban. It may be noted that the excess of the bladder cancer was presented mainly in those workers whose ages of the first exposure were under 19 years old, and the bladder cancer incidence seemed to be associated positively with the cumulative duration of exposure. The survey about the smoking history did not show any obvious relationship between smoking and the development of the bladder cancer. Moreover, it was seen that a trend of excessive in incidence of the nasopharyngeal cancer and the lymphosarcoma existed in this population.

The risk of cancer was analysed in a cohort of 604 male workers who had been engaged in manufacturing and/or handling benzidine and/or beta-naphthylamine during the period 1945-71 at two factories located in the city of Osaka. The cohort was followed up from 1 January 1970 to the date of death or 31 December 1986. The mean follow-up time was 16.1 years. A total of 84 deaths was found compared with 112.66 expected based on the mortality of the Osaka population. Thirty-six were found to be dead of malignant neoplasms; 9 stomach, 2 colon, 1 rectum, 3 liver, 1 bile duct, 1 pancreas, 1 maxillary sinus, 6 lung, 8 bladder, and 2 ureter neoplasms as well as 1 case of myeloid leukemia. Seven cases were ascertained on death certificates as neoplasms of uncertain behaviour, all of which were tumors of genitourinary organs except for one case of brain tumor. Cancers of genitourinary organs and tumors of uncertain behaviour showed statistically significant increased standardized ratios (SMR = 12.20, 4.89). The mean age of death of those having genitourinary organs including cancer was 59 years old, and the latent period between the first exposure and the occurrence of the disease was 19.7 years on average. Non-significant increased risks of cancers of the colon, rectum, liver and lung were observed among the workers exposed to benzidine. Among the 7 histologically confirmed cases of these cancers, there were 2 adenocarcinomas of the lung, 1 adenocarcinoma of the rectum, 2 hepatocellular carcinoma and 1 adenocarcinoma of the bile duct. Seven patients with genitourinary tumors were found to have died of other primary cancers.

Shanghai is the largest industrial centre in China and has a history of about 50 years in producing and applying benzidine derived dyes. A series of epidemiological studies on the carcinogenicity of benzidine and its derived dyes have been performed since 1979. This report describes three such studies. A case-control study was carried out on 344 cases of bladder cancer, each matched for age and sex, with a person without bladder cancer. Factors studied were occupational exposure, smoking, drinking, medical histories, and family history of bladder cancer and other carcinomas. The correlation between bladder cancer and occupational exposures (relative risk (RR) 5.71) was greater than that between bladder cancer and smoking (RR 1.53). A retrospective cohort study was conducted in seven dyestuffs factories where benzidine had served as an intermediate in the manufacture of dyes before 1976. The cohort was made up of 550 men and 186 women. The men were divided into two groups according to job; 354 were assigned to a presynthesis group and 196 to a postsynthesis group. Those in the presynthesis group were thought to have been exposed to benzidine and the subjects in the postsynthesis group were exposed mainly to its derived dyes. The 15 cases of bladder cancer diagnosed were all in the presynthesis group, although an excess of bladder cancer was also seen in the whole cohort. The standardised incidence ratio (SIR) of bladder cancer was 1918 in the whole cohort and 3500 in the presynthesis group. Moreover, the SIR of bladder cancer in a subgroup working directly with the assignment, transport, and mixing of benzidine was as high as 7500. A further retrospective cohort study was made on incidence of cancer among 1420 workers who used benzidine derived dyes in 43 textile printing and dyeing factories. No excess carcinoma was found. These results suggest that, in Shanghai, the main cause of bladder cancer is occupational exposure, especially to benzidine. The risk of bladder cancer, however, existed only in the presynthesis stage of dye manufacture.