Studying the Association of Polymorphic Variants of GSTM1 and GSTT1 Genes with Breast Cancer in Female Residents of Altai Krai

Evaluation of molecular markers GSTM1 and GSTT1 and clinical factors in breast cancer: case-control study and literature review

The study was conducted to evaluate the frequency of polymorphisms in GSTM1 and GSTT1 genes in patients with breast cancer compared with individuals without history of cancer, and the association of these polymorphisms with clinical/epidemiological parameters.There were evaluated 752 women (219 patients and 533 controls). Molecular analysis was performed by the Polymerase Chain Reaction (PCR). Statistical analysis was used multiple logistic regression and descriptive statistics.Age ≥50 years (OR =3.22, 95% CI =2.30 - 4.51, p <0.001) and alcohol consumption (OR =1.60, 95% CI =1.13 - 2.27, p = 0.008) were associated to the development of breast cancer, while smoking and null genotypes GSTM1 and GSTT1 presented no association. GSTM1 and GSTT1 polymorphisms presented no relationship with the clinical and histopathological parameters or molecular subtypes of breast cancer. Ninety-two percent of tumors were invasive ductal, 66% were grade II, 65% were larger than 2 cm, the stages II (35.3%) and III (31.2%) were the most prevalent, and 47.7% were molecular subtype luminal B.Individuals aged ≥50 years and alcohol consumers have more chance to developing breast cancer. GSTM1 and GSTT1 polymorphisms are not associated to the risk of breast cancer.

Possible Susceptibility Genes for Intervention against Chemotherapy-Induced Cardiotoxicity

Recent therapeutic advances have significantly improved the short- and long-term survival rates in patients with heart disease and cancer. Survival in cancer patients may, however, be accompanied by disadvantages, namely, increased rates of cardiovascular events. Chemotherapy-related cardiac dysfunction is an important side effect of anticancer therapy. While advances in cancer treatment have increased patient survival, treatments are associated with cardiovascular complications, including heart failure (HF), arrhythmias, cardiac ischemia, valve disease, pericarditis, and fibrosis of the pericardium and myocardium. The molecular mechanisms of cardiotoxicity caused by cancer treatment have not yet been elucidated, and they may be both varied and complex. By identifying the functional genetic variations responsible for this toxicity, we may be able to improve our understanding of the potential mechanisms and pathways of treatment, paving the way for the development of new therapies to target these toxicities. Data from studies on genetic defects and pharmacological interventions have suggested that many molecules, primarily those regulating oxidative stress, inflammation, autophagy, apoptosis, and metabolism, contribute to the pathogenesis of cardiotoxicity induced by cancer treatment. Here, we review the progress of genetic research in illuminating the molecular mechanisms of cancer treatment-mediated cardiotoxicity and provide insights for the research and development of new therapies to treat or even prevent cardiotoxicity in patients undergoing cancer treatment. The current evidence is not clear about the role of pharmacogenomic screening of susceptible genes. Further studies need to done in chemotherapy-induced cardiotoxicity.

Combined effects of GSTM1 and GSTT1 polymorphisms on breast cancer risk: A MOOSE-compliant meta-analysis and false-positive report probabilities test

Many molecular epidemiology studies have reported an association between the combined effects of glutathione S-transferase M1 (GSTM1) and glutathione S-transferase T1 (GSTT1) polymorphisms on breast cancer risk. However, the results have been controversial.A meta-analysis was performed to clarify this issue.Meta-analysis of observational studies in epidemiology guidelines was used. Pooled the crude odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using a random-effects model or fixed-effects model. Several subgroup analyses were conducted by ethnicity, source of control, matching, and menopausal status. In addition, we also performed sensitivity analysis and publication bias. Moreover, a false-positive report probability (FPRP) test was applied to assess positive results.A significantly increased breast cancer risk was observed in overall population (GSTM1 null/GSTT1 present [- +] vs GSTM1 present/GSTT1 present [+ +]: OR = 1.19, 95% CI: 1.03-1.36, GSTM1 null/GSTT1 null [- -] vs + +: OR = 1.63, 95% CI: 1.29-2.06, (- +) + GSTM1 present/GSTT1 null (+ -) vs + +: OR = 1.17, 95% CI: 1.05-1.31, (- +) + (+ -) + (- -) vs + +: OR = 1.27, 95% CI: 1.12-1.44, and - - vs (- +) + (+ -) + (+ +): OR = 1.39, 95% CI: 1.17-1.66) and several subgroup analyses, such as Caucasians, Indians, postmenopausal women, and so on. However, positive results were only considered noteworthy in overall population (- - vs + +: FPRP = 0.150 and (- +) + (+ -) + (- -) vs + +: FPRP = 0.162). Moreover, no significant association was observed when we used the trim and fill method to adjust the pooled data from all populations. Further, none of positive results of sensitivity analysis were considered noteworthy (FPRP >0.2).These positive findings should be interpreted with caution and indicate that an increased breast cancer risk may most likely result from false-positive results, rather than from true associations or biological factors on the combined effects of GSTM1 and GSTT1. Future studies should be based on sample sizes well-powered and attention needs to be paid to study design to further identify this issue.

Role of the renin-angiotensin-aldosterone system and the glutathione S-transferase Mu, Pi and Theta gene polymorphisms in cardiotoxicity after anthracycline chemotherapy for breast carcinoma

BACKGROUND

Anthracyclines are among the most active drugs against breast cancer, but can exert cardiotoxic effects eventually resulting in congestive heart failure (CHF). Identifying breast cancer patients at high risk of developing cardiotoxicity after anthracycline therapy would be of value in guiding the use of these agents.

AIMS

We determined whether polymorphisms in the renin-angiotensin-aldosterone system (RAAS) and in the glutathione S-transferase (GST) family of phase II detoxification enzymes might be useful predictors of left ventricular ejection fraction (LVEF) kinetics and risk of developing CHF. We sought correlations between the development of cardiotoxicity and gene polymorphisms in 48 patients with early breast cancer treated with adjuvant anthracycline chemotherapy.

METHODS

We analyzed the following polymorphisms: p.Met235Thr and p.Thr174Met in angiotensinogen (AGT), Ins/Del in angiotensin-converting enzyme (ACE), A1166C in angiotensin II type-1 receptor (AGTR1A), c.-344T>C in aldosterone synthase (CYP11B2), p.Ile105Val in GSTP1. Additionally, we analyzed the presence or absence of the GSTT1 and GSTP1 genes. A LVEF <50% was detected at least once during the 3 years of follow-up period in 13 out of 48 patients (27.1%).

CONCLUSION

RAAS gene polymorphisms were not significantly associated with the development of cardiotoxicity. GSTM1may be useful as a biomarker of higher risk of cardiotoxicity, as demonstrated in our cohort of patients (p=0.147).