Lack of association between GSTT1 polymorphism and endogenous or benzo[a]pyrene-induced sister chromatid exchanges as analyzed in metaphase or G2-phase lymphocytes

Women with polycystic ovary syndrome and other causes of infertility have a higher prevalence of GSTT1 deletion

RESEARCH QUESTION

Is GSTM1 and GSTT1 deletion associated with the development of polycystic ovary syndrome (PCOS)?

DESIGN

A case-control study was designed to investigate the association between GSTM1 and GSTT1 gene polymorphisms with PCOS. Blood samples from 201 women diagnosed with infertility were taken, of which 69 women were diagnosed with PCOS. Genomic DNA was extracted, and genotyping analyses were conducted by polymerase chain reaction-based methods. Odds ratios and 95% confidence intervals were calculated by unconditional logistic regression.

RESULTS

An increased risk of PCOS was found to be associated with GSTT1 null genotype (OR 4.890, 95% CI 2.261 to 9.122; P < 0.001). A strong association between GSTT1 null genotype was found with female infertility, regardless of the associated cause (OR 5.300, 95% CI 3.238 to 8.675; P < 0.001) as well as with the GSTM1 null genotype (OR 1.620, 95% CI 1.067 to 2.459; P = 0.026). A statistically significant association with the development of infertility was also found when carriers of the combined genotype GSTT1+/GSTM1+ was compared with carriers of the combined genotype GSTT1-/ GSTM1+ (OR 3.600 95% CI 1.864 to 6.956; P < 0.001). The two-way combination of GSTT1 and GSTM1 null genotypes resulted in an increased susceptibility to infertility development (OR 11.136; 95% CI 5.035 to 24.629; P < 0.001).

CONCLUSIONS

Carriers of GSTT1 null genotype seem to have higher susceptibility to developing PCOS and infertility from other causes. Also, GSTT1 null genotype, alone or in association, are related with increased susceptibility to infertility development, independently of its cause. GSTM1 null genotype is only associated with all cause of infertility when the GSTT1 is null.

Sister chromatid exchange, (SCE), High-Frequency Cells (HFCs) and SCE distribution patterns in peripheral blood lymphocytes of Spanish adult smokers compared to non-smokers

According to the International Agency for Research on Cancer, smoking tobacco is a major cause of cancer in humans. It causes about half of all male cancer deaths and an ever increasing number of cancer deaths in females. The aim of this study was to establish whether cigarette smoking increases sister chromatid exchanges (SCEs) in peripheral blood lymphocytes in two Spanish population groups; light and heavy smokers. The mean number of High-Frequency Cells (HFCs) was determined and, the SCE distribution pattern among the chromosomes was analysed represented by a ratio described below. A local sample of 101 adult smokers (n=48) and non-smokers (n=53), aged from 18 to 49 years, was studied using SCE levels in peripheral lymphocytes. Heavy smoking (≥ 10 cigarettes per day) increased significantly the SCE frequency and the HFC parameters. Neither age nor sex significantly influenced the frequencies in the groups studied.

Significant association of glutathione S-transferase T1 null genotype with esophageal cancer risk: a meta-analysis

Recent studies on the association between glutathione S-transferase T1 (GSTT1) polymorphism and risk of esophageal cancer showed inconclusive results. To clarify this possible association, we conducted a meta-analysis of published studies. Data were collected from the following electronic databases: Pubmed, Embase, and Chinese Biomedical Database (CBM). The odds ratio (OR) and its 95 % confidence interval (95 % CI) was used to assess the strength of this association. We summarized the data on the association between GSTT1 null genotype and risk of esophageal cancer in the overall population, and performed subgroup analyses by ethnicity. Finally, a total of 24 independent studies including a total of 7,801 subjects (2,965 cases and 4,836 controls) were eligible for meta-analysis. In the overall analysis, there was no significant association between GSTT1 null genotype and esophageal cancer risk (OR = 1.15, 95 % CI 0.99-1.33, P = 0.067). However, meta-analysis of adjusted ORs showed a significant association between GSTT1 null genotype and increased risk of esophageal cancer (OR = 1.30, 95 % CI 1.08-1.56, P = 0.005). Subgroup analyses by ethnicity showed there was an obvious association between GSTT1 null genotype and increased risk of esophageal cancer in East Asians (OR = 1.24, 95 % CI 1.10-1.39, P < 0.001), but not in Caucasians (OR = 0.89, 95 % CI 0.71-1.11, P = 0.300). There was no obvious risk of publication bias in this meta-analysis (Egger's test, P = 0.784). This meta-analysis demonstrates that GSTT1 null genotype is independently associated with increased risk of esophageal cancer, and a race-specific effect may exist in this association.

The radiosensitizing potential of glutaraldehyde on MCF7 breast cancer cells as quantified by means of the G2-chromosomal radiosensitivity assay

Glutaraldehyde (GA) is a high production volume chemical that is very reactive with a wide spectrum of medical, scientific and industrial applications. Concerning the genotoxic and carcinogenic effect of GA, controversial results have been reported, while in humans no studies with positive carcinogenic results for GA have been published. However, our previous study concerning the combined effects of exposure to both GA and ionising radiation (IR) in peripheral blood lymphocytes of healthy donors has shown that non-genotoxic doses of the chemical induces a statistically significant increase in chromosomal radiosensitivity. The lack of information concerning the radiosensitizing potential of GA on cancerous cells triggered us to test the radiosensitizing effect of GA on breast cancer cells (MCF7). For this purpose the G2-chromosomal radiosensitivity assay (G2-assay) was used. The assay involves G2-phase irradiation and quantitation of the chromosomal fragility in the subsequent metaphase. The experimental data show that 48 h exposure to GA, at doses that are not clastogenic to MCF7 breast cancer cells enhances G2-chromosomal radiosensitivity of this cell line. In an effort to evaluate whether the observed increase in GAs-induced G2-chromosomal radiosensitization is linked to GA-induced alterations in the cell cycle and feedback control mechanism, Mitotic Index analysis was performed. The results have shown that such a mechanism cannot be directly related to the observed GA-induced increase in G2-chromosomal radiosensitivity. Since increased G2-chromosomal radiosensitivity has been linked with cancer proneness, the radiosensitizing effect of GA at non-clastogenic doses highlights its potential carcinogenic profile.