Influence of methylenetetrahydrofolate reductase C677T polymorphism on the risk of lung cancer and the clinical response to platinum-based chemotherapy for advanced non-small cell lung cancer: an updated meta-analysis

Genetic polymorphisms as potential pharmacogenetic biomarkers for platinum-based chemotherapy in non-small cell lung cancer

Platinum-based chemotherapy (PBC) is a widely used treatment for various solid tumors, including non-small cell lung cancer (NSCLC). However, its efficacy is often compromised by the emergence of drug resistance in patients. There is growing evidence that genetic variations may influence the susceptibility of NSCLC patients to develop resistance to PBC. Here, we provide a comprehensive overview of the mechanisms underlying platinum drug resistance and highlight the important role that genetic polymorphisms play in this process. This paper discussed the genetic variants that regulate DNA repair, cellular movement, drug transport, metabolic processing, and immune response, with a focus on their effects on response to PBC. The potential applications of these genetic polymorphisms as predictive indicators in clinical practice are explored, as are the challenges associated with their implementation.

Methylenetetrahydrofolate reductase C677T gene polymorphism and the association with dyslipidemia in type 2 diabetic Palestinian patients

BACKGROUND

Dyslipidemia in diabetes is common and characterized by hypertriglyceridemia with decreased levels of high-density lipoprotein. The objective of this study was to assess the prevalence of MTHFR C677T polymorphism in Palestinian T2DM patients and to investigate the association between this polymorphism and lipid profile in diabetic patients with and without dyslipidemia.

METHODS

A total of 208 T2DM patients including 98 with dyslipidemia and 110 without dyslipidemia were enrolled in this study. The MTHFR C677T genotyping was conducted by PCR-RFLP followed by agarose gel electrophoresis.

RESULTS

There were no significant differences in either the genotype distribution or allele frequency in T2DM patients with or without dyslipidemia (37.8% CC, 54% CT, 8.2% TT vs. 48.2% CC, 41.8% CT, 11% TT; p = 0.209). However, among the dyslipidemic group, the TT carriers have a higher HDL level (46.8 ± 17.8) compared to (CC+CT) carriers (34.68 + 11.9) (p = 0.01). In the group without dyslipidemia, there was a significant elevation in diastolic blood pressure (DBP) among the CC carriers (83.6 ± 10.6) compared to those who carried at least one mutant allele (CT+TT) (78.1 ± 11.1) (p = 0.009).

CONCLUSIONS

The study shows that in our Palestinian population the MTHFR 677TT genotype lowers DBP significantly in patients without dyslipidemia and is related to increased level of HDL in diabetic dyslipidemia patients.

MTHFR C677T and A1298C polymorphisms and lung cancer risk in a female Chinese population

Objective

To examine the relationship between polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene and susceptibility to lung cancer in a female Chinese population.

Method

A hospital-based case-control study of 388 cases and 388 controls was conducted. Two polymorphisms in MTHFR were detected using TaqMan methods.

Results

The MTHFR C677T polymorphism was associated with the risk of lung cancer and lung adenocarcinoma. Carriers with the TT genotype of C677T were observed to have an increased risk of lung cancer and lung adenocarcinoma (the ORs were 1.550 and 1.588, respectively). By contrast, the A1298C polymorphism had a negative relationship with the risk of lung cancer and lung adenocarcinoma; compared with the AA genotype carriers, the CC genotype carriers had a lower risk of lung cancer and adenocarcinoma in the female Chinese population (ORs were 0.302 and 0.215, respectively). In the stratified analyses, we observed only the A1298C polymorphism in the CC genotype carriers with a statistically significant reduction in the risk of non-small-cell lung cancer, compared to the AA genotype carriers. No significant statistical association was found between the MTHFR gene polymorphisms and risk of the residual subtype of lung cancer.

Conclusion

This study provides evidence that the MTHFR C677T polymorphism may contribute to the development of lung cancer and lung adenocarcinoma in a female Chinese population. However, the MTHFR A1298C polymorphism may be associated with the decreasing risk of lung cancer.

Pharmacogenetics of platinum-based chemotherapy: impact of DNA repair and folate metabolism gene polymorphisms on prognosis of non-small cell lung cancer patients

Chemotherapy based on platinum compounds is the standard treatment for NSCLC patients with EGFR wild type, and is also used as second line in mutated EGFR patients. Nevertheless, this therapy presents poor clinical outcomes. ERCC1, ERCC2, XRCC1, MDM2, MTHFR, MTR, and SLC19A1 gene polymorphisms may contribute to individual variation in response and survival to platinum-based chemotherapy. The aim of this study was to investigate the influence of these polymorphisms on response and survival of NSCLC patients treated with platinum-based chemotherapy. A retrospective-prospective cohorts study was conducted, including 141 NSCLC patients. Polymorphisms were analyzed by PCR real-time with Taqman® probes. Patients with ERCC1 rs3212986-GG (p = 0.0268; OR = 2.50; CI_95% = 1.12-5.69) and XRCC1 rs25487-GG (p = 0.0161; OR = 2.99; CI_95% = 1.26-7.62) genotype showed significantly better ORR. Cox survival analysis revealed that patients carrying the MDM2 rs1690924-GG genotype (p = 0.0345; HR = 1.99; CI_95% = 1.05-3.80) presented higher risk of death. Furthermore, carriers of MTR rs1805087-A alleles (p = 0.0060; HR = 8.91; CI_95% = 1.87-42.42) and SLC19A1 rs1051266-AA genotype (p = 0.0130; HR = 1.74; CI_95% = 1.12-2.68) showed greater risk of progression. No influence of ERCC1 rs11615, ERCC2 rs13181, ERCC2 rs1799793, XRCC1 rs1799782, MDM2 rs1470383, MTHFR rs1801131, and MTHFR rs1801133 on platinum-based chemotherapy clinical outcomes was found. In conclusion, our results suggest that ERCC1 rs3212986, XRCC1 rs25487, MDM2 rs1690924, MTR rs1805087, and SLC19A1 rs1051266 gene polymorphisms may significantly act as predictive factors in NSCLC patients treated with platinum-based chemotherapy.

Lack of association between the MTHFRC677T polymorphism and lung cancer in a Turkish population

BACKGROUND

In this case-control study, we aimed to investigate the relationship between the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and lung cancer.

MATERIALS AND METHODS

Total 200 individuals including 100 patients with lung cancer and 100 controls were analyzed. Genotyping of MTHFR C677T was performed using PCR and RFLP methods.

RESULTS

The majority of the patients were men and 90% were smokers. We found that the risk ratio for development of LC was 13-times higher in smokers compared with non-smokers between patient and control groups in our study (OR:13.5, 95%CI:6.27-29.04, p:0.0001). Besides, the risk ratio for development of LC was nine times higher in individuals with cancer history in their family than those without cancer history (OR:9.65, 95%CI: 2.79-33.36; p:0.0001). When genotype distributions and allele frequencies were analyzed in the study groups, no significant difference was apparent (χ2:0.53, p=0.76). In addition, no correlation between genotypes of MTHFRC677T polymorphism and histological type of LC was found (χ2:0.99, p=0.60).

CONCLUSIONS

These results suggest that there was no association between the MTHFR C677T polymorphism and lung cancer in the Turkish population.

Pharmacogenomics of platinum-based chemotherapy sensitivity in NSCLC: toward precision medicine

Lung cancer is one of the leading causes of cancer-related death in the world. Platinum-based chemotherapy is the first-line treatment for non-small-cell lung cancer (NSCLC), however, the therapeutic efficiency varies remarkably among individuals. A large number of pharmacogenomics studies aimed to identify genetic variations which can be used to predict platinum response. Those studies are leading NSCLC treatment to the new era of precision medicine. In the current review, we provided a comprehensive update on the main recent findings of genetic variations which can be used to predict platinum sensitivity in the NSCLC patients.

Intensity-modulated radiotherapy and volumetric-modulated arc therapy have distinct clinical advantages in non-small cell lung cancer treatment

This study was conducted to compare the efficacy of intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) in delivering the planned dosage in the treatment of non-small cell lung cancer (NSCLC). Between September 2013 and March 2014, 125 NSCLC patients were randomly chosen and allocated to the IMRT group (n = 65) and VMAT group (n = 60). We compared multiple parameters such as target dose, organ dosimetry, monitor unit (MU) and time of therapy between IMRT and VMAT groups. The prescribed dose coverage of both planning techniques was 95 % of the planning target volumes (PTVs). PTV 95 % and homogeneous index in IMRT plan were greater than those in VMAT plan (both P < 0.05), while no significant difference in conformity index was observed (P > 0.05). The mean total lung V5 and V10 in VMAT group were markedly higher than those in IMRT group, but the V20, V30, and V40 in VMAT group were significantly lower (all P < 0.05), but no statistically significant difference was observed in V15 and V20 (P > 0.05). Furthermore, the planning spine and esophagus at risk volume showed no statistical significances in both groups (P > 0.05). MU of IMRT plan was about 4.2 % less than that of VMAT plan, which was statistically significant (P < 0.001). Both IMRT and VMAT had significant advantages in the treatment of NSCLC. The IMRT may be better for NSCLC patients with poor pulmonary function, and VMAT may be recommended for NSCLC patients with normal pulmonary function.

Methylenetetrahydrofolate reductase 677TT genotype may be associated with an increased lung cancer risk in North China: an updated meta-analysis

Background

Although many epidemiology studies have investigated the methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and their associations with lung cancer (LC), definite conclusions cannot be drawn. To clarify the effects of MTHFR polymorphisms on the risk of LC, we performed a meta-analysis in Chinese populations.

Material/Methods

Related studies were identified from PubMed, Springer Link, Ovid, Chinese Wanfang Data Knowledge Service Platform, Chinese National Knowledge Infrastructure (CNKI), and Chinese Biology Medicine (CBM) until 16 February 2014. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of the associations.

Results

A total of 11 studies with 2487 LC cases and 3228 controls were included in this meta-analysis. Overall, no significant association was found between MTHFR C677T polymorphism and LC risk when all studies in Chinese populations were pooled into this meta-analysis. In subgroup analyses stratified by geographical location and source of controls, significantly increased risk was found in North China (T vs. C: OR=1.28, 95% CI: 1.14–1.44; TT vs. CC: OR=1.67, 95% CI: 1.33–2.10; TT + CT vs. CC, OR=1.39, 95% CI=1.15–1.69; TT vs. CC + CT: OR=1.46, 95% CI: 1.03–2.06) and in population-based studies (TT vs. CC: OR=1.37, 95% CI: 1.14–1.65; TT vs. CC + CT: OR=1.25, 95% CI: 1.07–1.45).

Conclusions

This meta-analysis provides evidence that MTHFR C677T polymorphism may contribute to LC development in North China. Studies with larger sample sizes and wider spectrum of populations are warranted to verify this finding.

Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism: epidemiology, metabolism and the associated diseases

The Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism is associated with various diseases (vascular, cancers, neurology, diabetes, psoriasis, etc) with the epidemiology of the polymorphism of the C677T that varies dependent on the geography and ethnicity. The 5,10-Methylenetetrahydrofolate reductase (MTHFR) locus is mapped on chromosome 1 at the end of the short arm (1p36.6). This enzyme is important for the folate metabolism which is an integral process for cell metabolism in the DNA, RNA and protein methylation. The mutation of the MTHFR gene which causes the C677T polymorphism is located at exon 4 which results in the conversion of valine to alanine at codon 222, a common polymorphism that reduces the activity of this enzyme. The homozygous mutated subjects have higher homocysteine levels while the heterozygous mutated subjects have mildly raised homocysteine levels compared with the normal, non-mutated controls. Hyperhomocysteinemia is an emerging risk factor for various cardiovascular diseases and with the increasing significance of this polymorphism in view of the morbidity and mortality impact on the patients, further prevention strategies and nutritional recommendations with the supplementation of vitamin B12 and folic acid which reduces plasma homocysteine level would be necessary as part of future health education. This literature review therefore focuses on the recent evidence-based reports on the associations of the MTHFR C677T polymorphism and the various diseases globally.