Hiromasa Tsukino

Decreased Serum Free Testosterone in Workers Exposed to High Levels of Di-n-butyl Phthalate (DBP) and Di-2-ethylhexyl Phthalate (DEHP): A Cross-Sectional Study in China

Background Observations of adverse developmental and reproductive effects in laboratory animals and wildlife have fueled increasing public concern regarding the potential for various chemicals to impair human fertility. Objective Our objective in this study was to assess the effect of occupational exposure to high levels of phthalate esters on the balance of gonadotropin and gonadal hormones including luteinizing hormone, follicle-stimulating hormone, free testosterone (fT), and estradiol. Methods We examined urine and blood samples of 74 male workers at a factory producing unfoamed polyvinyl chloride flooring exposed to di-n-butyl phthalate (DBP) and di-2-ethylhexyl phthalate (DEHP) and compared them with samples from 63 male workers from a construction company, group matched for age and smoking status. Results Compared to the unexposed workers, the exposed workers had substantially and significantly elevated concentrations of mono-n-butyl phthalate (MBP; 644.3 vs. 129.6 μg/g creatinine, p < 0.001) and mono-2-ethylhexyl phthalate (MEHP; 565.7 vs. 5.7 μg/g creatinine, p < 0.001). fT was significantly lower (8.4 vs. 9.7 μg/g creatinine, p = 0.019) in exposed workers than in unexposed workers. fT was negatively correlated to MBP (r = −0.25, p = 0.03) and MEHP (r = −0.19, p = 0.095) in the exposed worker group. Regression analyses revealed that fT decreases significantly with increasing total phthalate ester score (the sum of quartiles of MBP and MEHP; r = −0.26, p = 0.002). Conclusion We observed a modest and significant reduction of serum fT in workers with higher levels of urinary MBP and MEHP compared with unexposed workers.

ALTERED METHYLATION OF MULTIPLE GENES IN CARCINOGENESIS OF THE PROSTATE

The methylation status of 7 genes was examined in four cell lines, 36 samples of benign prostatic hyperplasia (BPH), 20 samples of prostatic intraepithelial neoplasia (PIN) and 109 samples of prostate cancer (PCa), using methylation‐specific PCR (MSP): the pi‐class glutathione S‐transferase (GSTP1), retinoic acid receptor beta 2(RARβ2), androgen receptor (AR), death‐associated protein kinase (DAPK), tissue inhibitor of metalloproteinase‐3 (TIMP‐3), O6‐methylguanine DNA methyltransferase (MGMT), and hypermethylated in cancer‐1 (HIC‐1). The frequencies of methylation in PCa were 88% for GSTP1, 78% for RARβ2, 36% for DAPK, 15% for AR, 6% for TIMP‐3, and 2% for MGMT, whereas the values were 11% for AR and DAPK, 6% for TIMP‐3, 3% for GSTP1, and 0 for RARβ2 and MGMT in BPH. Aberrant methylation of the GSTP1 and RARβ2 genes was detected in 30% and 20% of PIN, respectively. Most samples of BPH and PCa were positive for HIC‐1 methylation. Regarding accumulation of methylated cancer‐related genes, there were significant correlations between PCa and BPH as well as PIN and BPH. In the present study, a high frequency of aberrant promoter methylation of the GSTP1 and RARβ2 genes was noted in PCa. Our findings suggest that methylation of cancer‐related genes may be involved in carcinogenesis of the prostate.

p53 Codon 72 polymorphism and urothelial cancer risk.

The p53 tumor suppressor gene is often mutated in various human cancers. Recently, the p53 codon 72 polymorphism has been extensively studied to determine the risk factors responsible for cancer formation. We investigated the genotype distribution of the p53 codon 72 polymorphism in 112 male urothelial cancer cases and 175 male unrelated non-cancer controls. The allelic frequencies in Japanese non-cancer controls were 0.58 (Arg) and 0.42 (Pro). There was no significant difference in the three genotype frequencies (Arg/Arg, Arg/Pro, Pro/Pro) of the p53 codon 72 between the urothelial cancer cases and the controls. However, stratifying by smoking status, we found that the frequency of the Pro/Pro genotype for smokers was significantly more than that for never-smokers (odds ratio (OR)=2.28, 95% confidence interval (95%CI)=1.12-4.66). Furthermore, we divided smoking status (pack-years) into quartiles (<20, 20-40, 40-60, >60). OR (Pro/Pro vs. Arg/Arg) for the lighter smokers (<20 pack-years) was higher than in other groups (OR=6.83). Our results suggest that the Pro/Pro genotype of the p53 codon 72 polymorphism increases the risk of urothelial cancer in smokers.

Bacteria of preoperative urinary tract infections contaminate the surgical fields and develop surgical site infections in urological operations.

Background: The risk factors for surgical site infection (SSI) following urological operations have not been clearly identified, although the presence of a preoperative urinary tract infection (UTI) is thought to be one risk factor. We studied potential risk factors to clarify when and how bacteria contaminate wounds and SSI develop.

E-cadherin gene polymorphism and risk of urothelial cancer.

The E-cadherin is important in cell-cell adhesion and in the development and maintenance of the epithelial phenotype. A -160C-->A polymorphism in the promoter region of E-cadherin has been shown to decrease gene transcription. This allelic variation may be a potential genetic marker that can help identify those individuals at higher risk for invasive/metastatic disease. We studied the effect of E-cadherin gene polymorphism on urothelial cancer susceptibility in a case control study of 314 urothelial cancer patients and 314 age-sex matched controls, to determine whether this polymorphism is a biomarker for the risk and how aggressive the disease is. The frequency with which the subjects carried E-cadherin A/A genotype was significantly higher in the urothelial cancer patients than in the healthy control subjects (OR=2.32, 95% CI 1.03-5.22). Subdividing urothelial cancer according to tumor differentiation and stage, we found no association between E-cadherin polymorphism and poorly-differentiation and invasiveness of urothelial cancer. Furthermore, no significant association between E-cadherin polymorphism and recurrence rate of urothelial cancer patients was found. The present study demonstrates for the first time that E-cadherin A/A genotype may be associated with susceptibility to urothelial cancer, but not with the progression of disease.

Cytochrome P450 (CYP) 1A2, sulfotransferase (SULT) 1A1, and N-acetyltransferase (NAT) 2 polymorphisms and susceptibility to urothelial cancer

Purpose Arylamines are suspected to be the primary causative agent of urothelial cancer in tobacco smoke. In the human liver, arylamines are N-hydroxylated by a cytochrome P450 (CYP)1A2-catalyzed reaction, which produces a substrate for O-esterification that can be catalyzed by N-acetyltransferases (NAT) or sulfotransferases (SULT). Recently, several polymorphisms of CYP1A2, SULT1A1, and NAT2 that affect their activities have been reported.Methods In this study, 306 Japanese patients with urothelial transitional cell carcinoma and 306 healthy controls were compared for frequencies of CYP1A2, SULT1A1, and NAT2 genotypes.Results The frequencies of NAT2 intermediate or slow acetylator genotype were significantly higher in the urothelial cancer patients than in the healthy control subjects [odds ratio (OR)=1.49, 95% confidence interval (95% CI) 1.06–2.09, OR=3.23, 95% CI 1.72–6.08, respectively]. Stratifying by amount of smoking, among subjects who consumed >33.5 pack-years and carried the SULT1A1 *1/*1 or NAT2 slow acetylator genotype, the OR was 1.73 (95% CI 1.01–2.97) whereas it was 7.31 (95% CI 1.90–28.05) in non-smokers who carried the homozygous wild genotype, respectively. The relationships between CYP1A2, SULT1A1, and NAT2 polymorphisms and clinical findings including tumor differentiation, stage, and recurrence rate were analyzed. Only associations between NAT2 genotype and pathological findings were admitted, and the higher OR of NAT2 intermediate and slow acetylator genotype was more likely to present to a low-grade tumor (G1) among heavy-smokers.Conclusions Our results suggest that SULT1A1 *1/*1 and NAT2 slow acetylator genotypes might modulate the effect of carcinogenic arylamines contained in tobacco smoke, and that the modulation of NAT2 intermediate and slow acetylator genotype has a tendency to present a higher risk for highly differentiated tumors among heavy-smokers.

Lack of Evidence for the Association of E-Cadherin Gene Polymorphism with Increased Risk or Progression of Prostate Cancer

Background: E-cadherin is an epithelial cell adhesion molecule, and decreased E-cadherin expression in human prostate cancer is associated with tumor grade and advanced clinical stage. A –160 C→A polymorphism in the promoter region of E-cadherin has been shown to decrease gene transcription. This allelic variation may be a potential genetic marker that can help identify those individuals at higher risk for invasive/metastatic disease. Materials and Methods: We studied the effect of E-cadherin gene polymorphism on prostate cancer susceptibility in a case control study of 219 prostate cancer patients and 219 male controls, to determine whether this polymorphism is a biomarker for the risk and how aggressive the disease is. Results: The genotype frequencies in the prostate cancer group were C/C: 0.607, C/A: 0.352, A/A: 0.041, and in the control group C/C: 0.671, C/A: 0.301, A/A: 0.027. A significant difference between the two groups was not found (p = 0.34), and the adjusted OR for A/A genotype was not statistically significant (OR = 1.66, 95% CI 0.58–4.78). Subdividing prostate cancer according to tumor differentiation and stage, we found no association between E-cadherin polymorphism and poor differentiation and invasiveness of prostate cancer. Conclusions: These data do not support an association between the E-cadherin genotype and the occurrence or progression of prostate cancer in Japanese populations.

Effects of cytochrome P450 (CYP) 2A6 gene deletion and CYP2E1 genotypes on gastric adenocarcinoma

Cytochrome P450 (CYP) 2A6 and CYP2E1 are enzymes with a high ability to activate a nitrosamine, 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanone (NNK), to its potent and ultimate carcinogens. The polymorphic CYP2A6 and CYP2E1 have been implicated in increased susceptibility to certain malignancies. In our study, 120 Japanese patients with gastric adenocarcinoma and 158 healthy controls were compared for frequencies of CYP2A6 and CYP2E1 genotypes. The frequency with which the subjects carried homozygotes of the CYP2A6 gene deletion allele, which causes lack of the enzyme activity, was significantly higher in the gastric cancer patients than in the healthy control subjects (OR = 3.14, 95% confidence interval (95% CI) = 1.05–9.41). Subdividing gastric adenocarcinoma according to tumor differentiation, patients with the well‐differentiated type were 4.9‐fold more likely to have the CYP2A6 homozygote deletion genotype (OR = 4.91, 95% CI 1.17–20.52). Stratifying by smoking status, we did not find the risk of CYP2A6 gene deletion allele in gastric adenocarcinoma. The CYP2E1 polymorphism detected by RsaI was not significantly different between gastric adenocarcinoma patients (40.8%) and the control population (44.3%). No statistically significant changes were observed when the CYP2E1 genotype was examined relative to tumor differentiation and smoking status. These results suggest that the CTY2A6 deletion is associated with gastric adenocarcinoma among Japanese populations.

Prevalence of Mycoplasma genitalium among female students in vocational schools in Japan

Objective: In Japan it was reported that about 9% of sexually active female teenagers had Chlamydia trachomatis. Most of them were asymptomatic, which may lead to continuing spread of the infection. Like C trachomatis, Mycoplasma genitalium is a pathogen in male non-gonococcal urethritis. However, few studies of the prevalence of M genitalium in the general population have been reported. The objective of this study was to determine the prevalence of M genitalium infection among younger females and to determine risk factors for this infection. Methods: The study was conducted between October 2005 and January 2006 using first voided urine specimens and questionnaires from female students of three vocational schools in the Miyazaki prefecture, Japan. C trachomatis was detected with Amplicor™ PCR. M genitalium was detected with inhibitor controlled real-time TaqMan™ PCR detecting the MgPa adhesion gene and with a PCR detecting the 16S rRNA. Risk factors associated with infection of M genitalium or C trachomatis were analysed with Fisher’s exact test. Results: Among 298 female, 249 (84%) had had experience of sexual intercourse. The prevalence of M genitalium was 2.8% (95% CI 0.76% to 4.86%) and the prevalence of C trachomatis was 8.8% (95% CI 5.31% to 12.36%). Conclusions: The risk factors of infection with M genitalium were more than five lifetime sexual partners and co-infection with C trachomatis.

Population-based study of asymptomatic infection with Chlamydia trachomatis among female and male students

There are few epidemiological studies of asymptomatic chlamydial infection among students in non-medical settings with minimal bias and improved accuracy; thus, useful data from screening among students are limited. We aimed to obtain accurate epidemiological information about asymptomatic chlamydial infection among students in non-medical settings. A population-based cross-sectional survey of 10,440 ≥18-year-old asymptomatic students who volunteered for a urine screening test for chlamydia was conducted. The prevalences of asymptomatic infection were 9.5% for women and 6.7% for men. Multivariate analysis revealed the risk factors to be a lifetime history of ≥4 sexual partners for women (odds ratio [OR] 3.17) and inconsistent condom use for men (OR 4.18). For both sexes, younger age at first intercourse was associated with a higher rate of inconsistent condom use. This study produced accurate epidemiological information on asymptomatic chlamydial infection. These results may contribute to the establishment of preventive countermeasures against such infection.