Effects of concurrent exposure to tributyltin and 1,1-dichloro-2,2 bis (p-chlorophenyl) ethylene (p,p'-DDE) on immature male Wistar rats

Tributyltin and 1, 1-dichloro-2, 2 bis (p-chlorophenyl) ethylene (p,p'-DDE) have been ubiquitously distributed over the world. In Japan, p,p'-DDE and tributyltin are ingested through marine products, in which these substances are accumulated through bio-concentration and the food chain. However, the consequence of potential combined hazards of these substances remains unknown. Therefore, the effects of concurrent exposure to 125 ppm p,p'-DDE and 25 ppm tributyltin were investigated in immature male Wistar rats by oral administration during puberty. In this study, tributyltin promoted the growth of pubertal male rats, while p,p'-DDE itself did not affect the growth but inhibited the growth enhancement by tributyltin. Furthermore, tributyltin reduced thymus weight but p,p'-DDE also prevented this weight reduction. Neither development of male sexual accessory organs nor sexual maturation was affected even by concurrent exposure to p,p'-DDE and tributyltin. No significant changes of serum testosterone, luteinizing hormone, follicle-stimulating hormone concentrations, and epididymal sperm numbers were observed with the administration of p,p'-DDE and/or tributyltin. These results indicate that sexual maturation, male reproductive organ development and sperm production is scarcely affected in immature male Wistar rats even by concurrent exposure to p,p'-DDE and tributyltin at a daily dose of ca. 2 mg/kg tributyltin and 10 mg/kg p,p'-DDE. Moreover, the simultaneous administration of p,p'-DDE with tributyltin counterbalanced the effects that were attributed to tributyltin alone.

EPHX1 polymorphisms and the risk of lung cancer: a HuGE review

BACKGROUND

Microsomal epoxide hydrolase 1 (EPHX1) plays an important role in both the activation and detoxification of tobacco-derived carcinogens. Polymorphisms at exons 3 and 4 of the EPHX1 gene have been reported to be associated with variations in EPHX1 activity. The aim of this study is to review and summarize the available molecular epidemiologic studies of lung cancer and EPHX1.

METHODS

We searched MEDLINE, Current Contents, and Web of Science databases for studies published before August 2004. We conducted a systematic review and meta-analysis of 13 case-control studies. Summary odds ratios and summary prevalence of the variant allele (genotype) of both polymorphisms in the EPHX1 gene were calculated using the DerSimonian and Laird method.

RESULTS

The low-activity (variant) genotype of EPHX1 polymorphism at exon 3 was associated with decreased risk of lung cancer (odds ratio = 0.65; 95% confidence interval = 0.44-0.96) in lung cancer risk among whites. In white populations, the high-activity (variant) genotype of EPHX1 polymorphism at exon 4 was associated with a modest increase in risk of lung cancer (1.22; 0.79-1.90) and the predicted low activity was associated with a modest decrease in risk (0.72; 0.43-1.22).

CONCLUSIONS

EPHX1 enzyme may act as a phase I enzyme in lung carcinogenesis. The low-activity genotype of EPHX1 gene is associated with decreased risk of lung cancer among whites.

Molecular monitoring of the developmental bacterial community in the gastrointestinal tract of Japanese infants

The dynamics of the developmental bacterial community in the Japanese neonatal gastrointestinal tract were examined by monitoring 16S ribosomal RNA gene (rDNA) diversity in fecal samples by PCR and denaturing gradient gel electrophoresis (DGGE). The results showed a certain pattern common in infants without antibiotic treatment, in which aerobes, e.g., Pseudomonas, appeared first and were then immediately replaced by facultative anaerobe, Enterococcus, Streptococcus, and Enterobacteriaceae through the first month, and finally strictly anaerobic Bifidobactrerium appeared.

Relation of surgery, tumor site, and age group to the loss of reality testing in Japanese patients with malignant tumors: a study of a hospital-based sample with a consultation-liaison service

The relation between surgery and the loss of reality testing (LRT) in Japanese patients with malignant tumors were examined, taking into account the influence of the tumor sites and age groups. The patients were comprised of 277 men and 225 women with malignant tumors in Kyushu University Hospital, Fukuoka, Japan, who underwent a check-up at the Department of Neuropsychiatry for the first time using the consultation-liaison system. Those with known schizophrenia, dementia, mental retardation, and paranoid or schizoid (schizotypal) personality disorder were excluded. Surgery was statistically significantly associated with LRT in elderly men (> or =65 years of age), and in men with malignant tumors of the digestive organs (odds ratio [OR], 9.7; 95% confidence interval [95% CI], 3.2-29.3). Even after adjusting for tumor site and age, surgery was statistically significantly associated with LRT in men (OR, 2.6; 95% CI, 1.4-4.6) and nearly significantly associated in women (OR, 1.8; 95% CI, 0.9-3.6). There were no material associations between surgery and LRT in patients with malignant tumors of sex-specific organs or the head and neck area. The present study showed a positive relationship between surgery and LRT in Japanese men and women with malignant tumors. The association was stronger in elderly patients. As for tumor site, surgery was most strongly associated with an increased risk of LRT in patients with malignant tumors of the digestive organs.

CYP1A1 inducing potential of airborne particulate extracts collected during a 25-year period (1975-2000)

Samples of airborne particles from Sapporo, the capital of Hokkaido, Japan, were collected between 1975 and 2000. Major polycyclic aromatic hydrocarbons (PAHs) included in the extracts of airborne particles were investigated for their mutagenicity and potential for inducing drug-metabolizing enzyme cytochrome P450 (CYP)1A1, which is considered to be responsible for the activation of PAHs in airborne particle extracts, as well as in cigarette smoke, to carcinogens and is associated with risk of several cancers. There was a dose-related increase in CYP1A1 activity in human lymphoblastoid cells after exposure to airborne particulates containing PAHs. The mutagenicity of the airborne particles collected in summer was lowest and for those collected in spring was lower than in autumn or winter. Likewise, the winter sample had the strongest CYP1A1 inducing potential while the summer sample had the weakest. CYP1A1 inducing potency was strongly related to the amount of benzo(k)fluorathene (Spearman's rank correlation coefficient (gamma) = 0.97), benzo[a]pyrene g = 0.96), benzo[g,h,i]perylene (gamma = 0.94), benz[a]anthracene (g = 0.93), chrysene (gamma = 0.93) in the extracts during the 25-year period, while the enzyme activity was measurably related to the amount of pyrene (gamma = 0.64) and fluorathene (gamma = 0.54). During the 25-year period, CYP1A1 inducing potential decreased every year together with a decrease in PAHs in the airborne particle extracts. CYP1A1 inducing potential may be one of the most convenient biomarkers with which to estimate the overall carcinogenicity/mutagenicity of airborne particle extracts.

Methylenetetrahydrofolate reductase polymorphism, alcohol intake, and risks of colon and rectal cancers in Korea

Several, but not all, studies have reported that a variant genotype of the polymorphism (C677T) of 5,10-methylenetetrahydrofolate reductase (MTHFR), an enzyme in folate metabolism, is associated with a decreased risk of colorectal cancer. A case-control study was conducted to investigate the association of MTHFR polymorphism and heavy alcohol intake to colon and rectal cancer in Korean. Cases were a consecutive series of patients with histologically confirmed, incident colorectal cancer who were admitted to two university hospitals in Seoul, Korea between 1998 and 2000, and controls were selected at the same hospitals. A total of 243 cases (colon 111, rectum 132) and 225 controls were enrolled. While the genotype of MTHFR was not associated with the overall risk of colorectal cancer, increased colon cancer risk was found to be associated with the CT and TT genotypes combined (multivariate odds ratio [OR] 2.01, 95% confidence interval [CI] 1.14-3.53) compared with the wild type. The risk of rectal cancer was found to be, though statistically non-significant, lower in those with the CT and TT genotypes combined (multivariate OR 0.67, 95% CI: 0.43-1.07). Those consuming two or more drinks per day (30 g+/day) had nearly twice the colorectal cancer risk (multivariate OR 1.94, 95% CI 1.03-3.68) of light or non-drinkers (<5 g/day). The present study did not find a reduced risk of colorectal or rectal cancer among those with a variant genotype of the MTHFR polymorphism, but observed rather an increased risk of colon cancer, suggesting that the effects of the MTHFR genotype may differ in populations with different levels of folate intake.

Association of metabolic gene polymorphisms with tobacco consumption in healthy controls

Polymorphisms in genes that encode for metabolic enzymes have been associated with variations in enzyme activity between individuals. Such variations could be associated with differences in individual exposure to carcinogens that are metabolized by these genes. In this study, we examine the association between polymorphisms in several metabolic genes and the consumption of tobacco in a large sample of healthy individuals. The database of the International Collaborative Study on Genetic Susceptibility to Environmental Carcinogens was used. All the individuals who were controls from the case-control studies included in the data set with information on smoking habits and on genetic polymorphisms were selected (n = 20938). Sufficient information was available on the following genes that are involved in the metabolism of tobacco smoke constituents: CYP1A1, GSTM1, GSTT1, NAT2 and GSTP1. None of the tested genes was clearly associated with smoking behavior. Information on smoking dose, available for a subset of subjects, showed no effect of metabolic gene polymorphisms on the amount of smoking. No association between polymorphisms in the genes studied and tobacco consumption was observed; therefore, no effect of these genes on smoking behavior should be expected.

Genetic polymorphisms and environmental risk of lung cancer: a review

Lung cancer results from man-made and natural environmental exposures acting in concert with both genetic and acquired characteristics. Chronic inhalation of cigarette smoke is a major risk factor, and environmental tobacco exposure can cause lung cancer in life-long neversmokers. Air pollution, indoor-radon exposure, occupational exposures, dietary, physical activity, and reproductive history have been identified as independent or contributing risk factors for lung cancer. Because only a small portion of smokers develops the disease, genetic susceptibility can contribute to the risk. Developments in molecular biology have led to the discovery of biological markers that increase predisposition to lung carcinogenesis. Therefore, the high-risk genotype of an individual can be determined easily. Because of the great number of carcinogen-activating and -detoxifying enzymes, the variation in their expression, the complexity of exposures to tobacco carcinogens, and the existence of multiple alleles at loci of those enzymes results in differential susceptibilities of individuals. As lung cancer is a multifactorial disease, an improved understanding of the interplay of environmental and genetic polymorphisms at multiple loci can help identify individuals who are at increased risk for lung cancer. Hopefully, in the future we will be able to screen for lung cancer susceptibility by using specific biomarkers.

Risk modification by CYP1A1 and GSTM1 polymorphisms in the association of environmental tobacco smoke and lung cancer: a case-control study in Japanese nonsmoking women

Genetic backgrounds may modify the association of environmental tobacco smoke (ETS) with lung cancer risk. Polymorphisms of both the activating and detoxifying enzymes, cytochrome P4501A1 (CYP1A1) and glutathione-S-transferase M1 (GSTM1), may be important as genetic factors. We conducted a multicenter case-control study in Japanese nonsmoking women. Cases were women aged 30-89 years and newly diagnosed as having lung cancer from November 1997 to March 2001 in 4 study areas. We also recruited age-matched (5-year strata) and hospital-matched nonsmoking controls. A total of 158 cases and 259 hospital controls supplied blood for genotyping. Detailed information on ETS exposure from husbands and that in other situations and on potential confounders was collected by interview. Odds ratios (ORs) were estimated by using conditional logistic models. We found no increase in the risk of lung cancer for CYP1A1 Msp I genotypes. For the GSTM1 null genotype vs. nonnull genotype, the OR was 1.37 [95% confidence interval (CI) 0.90-2.09], which indicated a somewhat increased risk for the GSTM1 null genotype. A gene-environment interaction was suggested, with combined GSTM1 null genotype and high-dose ETS exposure (>/=40 pack-years by husbands) conferring significantly higher risk (OR = 2.27, 95% CI 1.13-4.57) compared to the GSTM1 nonnull genotype and low-dose ETS exposure (<40 pack-years). Our results do not support a major role of Msp I polymorphism of the CYP1A1 gene as a risk factor for lung cancer among nonsmoking women. In contrast, the GSTM1 null genotype posed an increased, although not significant, risk among them. Additional studies are warranted to confirm the ETS-GSTM1 polymorphism interaction suggested in our present study.

The experiences of smoking in school children up to and including high school ages and the current status of smoking habits; a survey of male high school students in Japan

OBJECTIVES

The burden of tobacco-induced cancer is so heavy that every country should give the highest priority to tobacco control in its fight against cancer. The purpose of the present study was to investigate the actual conditions of tobacco smoking among boys in Japan.

METHODS

A self-administered questionnaire survey. Two thousand and fourteen high school boys in Fukuoka City, Japan, answered unsigned self-administered anonymous questionnaires about tobacco smoking.

RESULTS

Among 2014 students, 10.9% were current smokers. The rates of current smokers increased with the school age: 6.3% in the first grade; 11.3% in the second grade; and 15.5% in the third grade (P(trend)<0.01). A total of 35.1% of students had the experience of smoking and 30% experienced smoking before entering high school. Of the students with smoking experience, 28.6% answered that they started smoking because their friends had offered them cigarettes and 52.5% of current smokers bought cigarettes from vending machines.

CONCLUSIONS

Health education for anti-smoking in all primary and secondary schools as well as restriction of cigarette vending machines should be strongly recommended.

Genetic influences on smoking behavior and nicotine dependence: a review

Molecular epidemiologic studies suggest genetic factors in the etiology of smoking behavior. Dopamine receptor genes, transporter genes (serotonin and dopamine), and other genes related to metabolism of nicotine are plausible functional candidate genes. Research examining the role of allelic variation in those genes is being actively pursued with respect to nicotine dependence as well as personality characteristics and mental disorders. Some of these genes were reported to be connected with schizophrenia. Although nicotine dependence itself is one of the mental disorders according to the fourth edition of Diagnostic and Statistical Manual of Mental Disorders and the World Health Organization's International Statistical Classification of Diseases and Related Health Problems-10 nomenclature, the high comorbidity between nicotine dependence and other mental disorders such as schizophrenia or affective disorders has been noted. Therefore, the relationship between those mental disorders and tobacco addiction should be cleared up considering the interactive effect of genetic and environmental factors.

[Comparison of the effectiveness of psychiatric day care treatment between Japan and western countries: a review]

Over the last two decades, day care (DC) treatment for mentally ill patients has come into wide use in Japan, following the precedents get in Western countries providing evidence of effectiveness. Several studies to examine the efficacy of DC treatment have already been performed in Japan. However, they were limited to chronic schizophrenic patients as subjects, and therefore the findings showed only improvement of the negative symptoms of schizophrenia. In contrast, Western studies have included heterogeneous mental disorders, and some showed DC was effective not only for treatment of global mental dysfunction but also for that of antisocial or violent behavior, drug dependence, emotional distress, and other characteristic disorders. Several Japanese and Western studies have shown DC treatment to be superior to outpatient treatment for relieving psychiatric symptoms. Regarding reduction of readmission rate, the Western studies were not supportive, but some Japanese studies showed that DC treatment was preventive against readmission as long as the follow up period was brief (within two or two and a half years). These findings suggested that the effectiveness of DC treatment may be limited. However, recently, medication against negative symptoms of schizophrenia has been revolutionary changing, offering the possibility that the combination of DC treatment and appropriate drug therapy may overcome the great obstacle of rehabilitating mentally ill patients in society. It is also very important that an evidence-based, standardized methodology of DC treatment should be immediately established in Japan.

CYP1A1 T3801 C polymorphism and lung cancer: a pooled analysis of 2451 cases and 3358 controls

CYP1A1 is involved in the metabolism of benzopyrene, a suspected lung carcinogen; it is therefore conceivable that genetically determined variations in its activity modify individual susceptibility to lung cancer. The role of the CYP1A1 MspI polymorphism in lung cancer has been widely studied but has not been fully clarified. We have included 2,451 cases and 3,358 controls in a pooled analysis of 22 case-control studies on CYP1A1 and lung cancer risk. We found a clear association between the CYP1A1 homozygous MspI restriction fragment length polymorphism (RFLP) and lung cancer risk in Caucasians (age- and gender-adjusted odds ratio = 2.36; 95% confidence interval 1.16-4.81); other associations were weaker or not statistically significant. The association with the homozygous variant was equally strong for squamous cell carcinomas and adenocarcinomas among Caucasians. We analyzed the risk by duration of smoking: for Caucasian subjects with the MspI RFLP combined variants (homozygotes plus heterozygotes), the increase in the risk of lung cancer was steeper than among the individuals with the homozygous reference allele. Our analysis suggests that Caucasians with homozygous variant CYP1A1 polymorphism have a higher risk of lung cancer. The data were more consistent among Caucasians, with a strong association between the homozygous variant in both squamous cell carcinomas and adenocarcinomas, and a stronger association in men than in women. The analyses were more inconsistent and failed to reach statistical significance in Asians. This observation might be due to design specificities or unknown effect modifiers in the Asian studies.

Polymorphism in GSTM1, GSTT1, and GSTP1 and Susceptibility to Lung Cancer in a Japanese Population

Polymorphisms in glutathione S-transferases (GSTs) may predispose to lung cancer through deficient detoxification of carcinogenic or toxic constituents in cigarette smoke, although previous results have been conflicting. Three GST polymorphisms (GSTM1, GSTT1 and GSTP1) were determined among 86 male patients with lung carcinomas and 88 healthy male subjects. We found no significant increase in the risk of lung cancer for any genotypes for the nulled GSTM1 [odds ratio (OR)=2.0; 95% confidence interval (95% CI)= 0.8-5.3], the nulled GSTT1 (OR=2.0; 95% CI=0.8-5.1) or the mutated (the presence of a Val-105 allele) GSTP1 (OR=0.96; 95% CI=0.4-5.5). The GST polymorphisms alone may thus not be associated with susceptibility to lung carcinogenesis in male Japanese. However, individuals with a concurrent lack of GSTM1 and GSTT1 had a significantly increased risk (OR=2.7; 95% CI=1.0-7.4) when compared with those having at least one of these genes. No other combinations were associated with lung cancer risk. These results suggest that there may be carcinogenic intermediates in cigarette smoke that are substrates for both GSTM1 and GSTT1 enzymes and that lung cancer risk is increased for individuals who are doubly deleted at GSTM1 and GSTT1 gene loci. Additional large studies are needed to confirm this observation.

Relation of plasma folate and methylenetetrahydrofolate reductase C677T polymorphism to colorectal adenomas

BACKGROUND

Folate intake may be related to decreased risk of colorectal cancer and adenomas. Methylenetetrahydrofolate reductase (MTHFR) is a key regulatory enzyme in folate metabolism. We examined the relation between plasma folate status and colorectal adenomas with reference to effect modification by the genetic polymorphism (C677T) of MTHFR.

METHODS

Study subjects were middle-aged Japanese men: 177 cases of colorectal adenomas and 192 controls with normal total colonoscopy. Statistical adjustment was made for hospital, rank in the Self Defense Forces, alcohol use, smoking, and body mass index.

RESULTS

Plasma folate levels were slightly lower in adenoma cases than in controls. Adjusted odds ratio (OR) for high (>5.50 ng/ml) versus low plasma folate levels was 0.72 (95% CI: 0.46-1.14). As compared with subjects with the CC or CT genotype having low plasma folate levels, those with the TT genotype showed a decreased risk of colorectal adenomas when they had high levels of plasma folate (adjusted OR = 0.58, 95% CI: 0.21-1.61), and an increased risk when they had low folate levels (adjusted OR = 2.13, 95% CI: 0.82-5.54). There was no clear relation between plasma folate and colorectal adenomas among those with the CC or CT genotype.

CONCLUSIONS

The findings suggest an interaction between folate and the MTHFR genotype on colorectal adenomas.

Novel Nonsynonymous Polymorphisms of the CYP1A1 Gene in Japanese

We found five novel nonsynonymous polymorphisms of the human CYP1A1 gene from Japanese individuals. The five single nucleotide polymorphisms (SNP) in exon 7 (2346_2347 ins T, 2414T>A, 2461C>T, 2500C>T and 2546C>G causing premature stop codon, Ile(448)Asn, Arg(464)Cys, and Arg(477)Trp and Pro(492)Arg, respectively) were as follows:SNP, 030212Saito001; GENE NAME, CYP1A1; ACCESSION NUMBER, X02612; LENGTH, 25 base; 5'-GTCAACCCATCT-/TGAGTTCCTACCT-3'.SNP, 030212Saito002; GENE NAME, CYP1A1; ACCESSION NUMBER, X02612; LENGTH, 25 base; 5'-GTGAGAAGGTGAT/ATATCTTTGGCAT-3'.SNP, 030212Saito003; GENE NAME, CYP1A1; ACCESSION NUMBER, X02612; LENGTH, 25 base; 5'-GAGACCGTTGCCC/TGCTGGGAGGTCT-3'.SNP, 030212Saito004; GENE NAME, CYP1A1; ACCESSION NUMBER, X02612; LENGTH, 25 base; 5'-ATCCTGCTGCAAC/TGGGTGGAATTCA-3'.SNP, 030212Saito005; GENE NAME, CYP1A1; ACCESSION NUMBER, X02612; LENGTH, 25 base; 5'-TGGACATGACCCC/GCATCTATGGGCT-3'.

Genetic polymorphisms and lung cancer susceptibility: a review

Lung cancer is a major cause of cancer-related death in the developed countries and the overall survival rate has still an extremely poor. Cigarette smoking is an established risk factor for lung cancer although a possible role for genetic susceptibility in the development of lung cancer has been inferred from familial clustering of the disease and segregation analyzes. Everyone may have a unique combination of polymorphic traits that modify genetic susceptibility and response to drugs, chemicals and carcinogens. Developments in molecular biology have led to growing interest in investigation of biological markers, which may increase predisposition to lung carcinogenesis. Therefore, the high-risk genotype of an individual could be determined easily. As there are the great number of carcinogen-activating and -detoxifying enzymes, the variation in their expression and the complexity of exposures to tobacco carcinogens, the existence of multiple alleles at loci of those enzymes may result in differential susceptibilities of individuals. This review summarize data addressing the relationships of lung cancer to markers of genetic susceptibility genes, including metabolic polymorphisms other than well-investigated cytochrome P450s or glutathione S-transferases, DNA repair genes and the p53 tumor suppressor gene. Among genetic polymorphisms reviewed here, myeloperoxidase gene (a G to A mutation) and microsomal epoxide hydrolase exon 4 polymorphism (substitution of Arg for His) were significantly associated with lung cancer risk. As lung cancer is a multifactorial disease, an improved understanding of the interplay of environmental and genetic polymorphisms at multiple loci may help identify individuals who are at increased risk for lung cancer. Hopefully, in the future we will be able to screen for lung cancer susceptibility by using specific biomarkers.

Efficacy of day care treatment against readmission in patients with schizophrenia: A comparison between out-patients with and without day care treatment

The present study examined the efficacy of day care (DC) treatment against readmission to a mental hospital. Subjects were 65 out-patients with chronic schizophrenia after discharge. Day care treatment was defined as positive if patients were under DC treatment constantly for 4 months or more with a frequency of at least one visit per week. Information regarding demographic and disease-related factors was obtained from medical records at the time of discharge. Logistic regression analysis was used to calculate odds ratios (OR) and 95% confidence intervals (CI) with adjustment for confounding variables. The modestly preventive efficacy of DC treatment against readmission was observed within 2 years after discharge (adjusted OR 0.52; 95% CI 0.12-2.35). The present findings suggest that DC treatment may be preventive against readmission for schizophrenic out-patients.

Genetic polymorphism of enzymes involved in xenobiotic metabolism and the risk of lung cancer

Chronic inhalation of cigarette smoke is a major risk factor for the development of lung cancer. It has been suggested that genetic susceptibility may contribute to the risk, because only a small portion of smokers develops the disease. Several polymorphisms that involve the metabolic activation or detoxification of carcinogens derived from cigarette smoke have been found to be associated with lung cancer risk. Many studies have focused on the relation between the distribution of polymorphic variants of different forms of the metabolic enzymes and lung cancer susceptibility. In this respect two groups of genetic polymorphisms of enzymes involved in xenobiotic metabolism, cytochrome P450 (CYP) and glutathione S-transferases (GSTs), have been discussed.CYP multigene superfamily consists of 10 subfamilies (CYP1-CYP10). A positive association between development of lung cancer and the mutant homozygous genotype ofCYP1A1 gene has been reported in several Japanese populations but such an association has not been observed in either Caucasians or African-Americans. The relation betweenCYP2D6 and lung cancer remains conflicting and inconclusive. Several polymorphisms have been identified at theCYP2E1 locus. No definitive link between the polymorphisms ofCYP2E1 and the risk of lung cancer has, however, been identified. The role of otherCYP2 isoforms in lung carcinogenesis has not been sufficiently investigated.GSTs form a superfamily of genes consisting of five distinct families, namedGSTA, GSTM, GSTP, GSTT andGSTS. The role ofGSTM, GSTT1 orGSTP1 polymorphism in modifying the lung cancer risk may be more limited than has been so far anticipated.Although some genetic polymorphisms discussed here have not shown significant increases/decreases in risk, individuals with differing genotypes may have different susceptibilities to lung cancer. Hopefully, in future studies it will be possible to screen for lung cancer using specific biomarkers.

Genetic polymorphisms of cytochrome P450 1A1 and risk of gallbladder cancer

The relation between cytochrome P4501A1 (CYP1A1) gene polymorphisms and the risk of gallbladder cancer was examined. To clarify individual differences in susceptibility to gallbladder carcinogenesis, we investigated the frequency of the Mspl and Ile-Val polymorphisms of the CYP1A1 gene, in 52 patients with gallbladder cancer (32 females, 20 males) and 104 healthy controls (64 females, 40 males). We then examined the relationship between the CYP1A1 polymorphisms and the development of gallbladder cancer in members of both sexes. A statistical difference in the frequencies of the MspI and Ile-Val polymorphisms or their alleles (ml, m2 and Ile, Val) was not observed in the male patients and controls. Among females, however, the frequencies of genotypes C and Ile/Val were significantly higher (p < 0.05) in the patients than in their controls. Moreover, the frequency of the hetero genotype Ile/Val was statistically higher (p < 0.05) in the female patients than in the male patients. This study demonstrated a significant over-representation of genotypes C and Ile/Val in female patients with gallbladder cancer. Females with genotypes C and/or Ile/Val may have a high genetic susceptibility to the development of gallbladder cancer.

Recognition of the deleterious effects of smoking among senior high school male students

The purpose of this study was to evaluate the prevalence of, attitudes towards, and knowledge about cigarette smoking among senior high school male students with different levels of academic ability. Self-administered anonymous questionnaires were distributed to 2014 students in July 2001. The prevalence of current smokers was 10.9% overall. The percentage of nonsmokers increased with academic ability level in both first and second graders. Students who recognize that cigarette smoking is associated with various diseases were more numerous than those reported in a nationwide Japan survey. Their recognition regarding the deleterious effects of smoking inclined toward diseases of the respiratory system. Correct knowledge concerning the detrimental effects of smoking on 10 selected diseases differed according to academic ability levels. They also thought that environmental tobacco smoke exposure was harmful to nonsmokers' health (86.6%). Although they fully understood the harmful effects of smoking, the percentage of current smokers who wanted to quit smoking (24.7%) was somewhat lower than that of those who did not (30.1%). A considerable number of current smokers, 95 of 219, had not made up their mind to quit smoking. To reduce the numbers of adult smokers, it is important not only to prevent students from starting to smoke or to encourage smokers to quit but also to guide undecided smokers in how to quit.

Metabolic gene polymorphism frequencies in control populations

Using the International Project on Genetic Susceptibility to Environmental Carcinogens (GSEC) database containing information on over 15,000 control (noncancer) subjects, the allele and genotype frequencies for many of the more commonly studied metabolic genes (CYP1A1, CYP2E1, CYP2D6, GSTM1, GSTT1, NAT2, GSTP, and EPHX) in the human population were determined. Major and significant differences in these frequencies were observed between Caucasians (n = 12,525), Asians (n = 2,136), and Africans and African Americans (n = 996), and some, but much less, heterogeneity was observed within Caucasian populations from different countries. No differences in allele frequencies were seen by age, sex, or type of controls (hospital patients versus population controls). No examples of linkage disequilibrium between the different loci were detected based on comparison of observed and expected frequencies for combinations of specific alleles.