Smoking and hOGG1 Ser326Cys polymorphism contribute to lung cancer risk: evidence from a meta-analysis

Oxidative genomic damage in humans exposed to high indoor radon levels in Northeast Brazil

Radon gas inhalation is the main source of exposure to ionizing radiation by humans. There is still lack in knowledge concerning the chronic and indirect effects of exposure to this carcinogenic factor. Therefore, the aim of this work is to analyze the levels of oxidative genomic damage in inhabitants of a medium-high background radiation area (HBRA) (N = 82) in Northeastern Brazil and compare them with people living in a low background radiation area (LBRA) (N = 46). 8-hydroxy-2-deoxyguanosine (8-OHdG) was quantified in urine, Ser326Cys polymorphism was determined in the hOGG1 gene and indoor radon was measured. HBRA houses had 6.5 times higher indoor radon levels than those from LBRA (p-value < 0.001). The 8-OHdG mean (95% confidence interval) were significantly different, 8.42 (5.98-11.9) ng/mg creatinine and 29.91 (23.37-38.30) ng/mg creatinine for LBRA and HBRA, respectively. The variables representing lifestyle and environmental and occupational exposures did not have a significant association with oxidized guanosine concentrations. On the other hand, lower 8-OHdG values were observed in subjects that had one mutant allele (326Cys) in the hOGG1 gene than those who had both wild alleles (Ser/Ser (p-value < 0.05). It can be concluded that high radon levels have significantly influenced the genome oxidative metabolism and hOGG1 gene polymorphism would mediate the observed biological response.

Lung Cancer in Women

BACKGROUND

Lung cancer is the leading cause of cancer-related death for women in the United States. Clinical characteristics, histology, epidemiology, and treatment responses are unique for women with lung cancer.

METHODS

Literature search of MEDLINE publications from 1989 to 2021 was conducted for lung cancer in women. Subsequent narrative review focused on identified differences in risk factors, diagnosis, and treatment of importance to the surgical care of these patients.

RESULTS

Studies investigating lung cancer, in which sex-differences are explored, demonstrated differences in risk factors, histology, and treatment response among women, with a significant post-surgical survival advantage over men (41.8 months vs 26.8 months, p=0.007) and greater clinical benefit from anti-PD1 combined with chemotherapy (HR=0.44, 95% CI: 0.25-0.76) compared with men (HR=0.76, 95% CI: 0.64-0.91). Smoking remains a dominant risk factor and multiple clinical trials suggest lung cancer screening provides greater benefit for women. However, young non-smoking patients with lung cancer are 2-fold more likely to be female, advocating for broader sex-based screening criteria. Potential roles of genetic mutations, estrogen signaling, and infectious elements in sex-based differences in presentation, histology, prognosis and treatment response are explored.

CONCLUSIONS

Overall, much remains unknown regarding how sex influences lung cancer risk, treatment decisions and outcomes. However, evidence of specific differences in presentation, environmental risk, molecular drivers, and mutational burden support the need to better leverage these sex-associated differences to further improve detection, diagnosis, surgical outcomes and systemic regimens in order to advance the overall care strategy for women with lung cancer.

Roles of DNA repair enzyme OGG1 in innate immunity and its significance for lung cancer

Cytokines are pivotal mediators of the immune response, and their coordinated expression protects host tissue from excessive damage and oxidant stress. Nevertheless, the development of lung pathology, including asthma, chronic obstructive pulmonary disease, and ozone-induced lung injury, is associated with oxidant stress; as evidence, there is a significant increase in levels of the modified guanine base 7,8-dihydro-8-oxoguanine (8-oxoG) in the genome. 8-OxoG is primarily recognized by 8-oxoguanine glycosylase 1 (OGG1), which catalyzes the first step in the DNA base excision repair pathway. However, oxidant stress in the cell transiently halts enzymatic activity of substrate-bound OGG1. The stalled OGG1 facilitates DNA binding of transactivators, including NF-κB, to their cognate sites to enable expression of cytokines and chemokines, with ensuing recruitments of inflammatory cells. Hence, defective OGG1 will modulate the coordination between innate and adaptive immunity through excessive oxidant stress and cytokine dysregulation. Both oxidant stress and cytokine dysregulation constitute key elements of oncogenesis by KRAS, which is mechanistically coupled to OGG1. Thus, analysis of the mechanism by which OGG1 modulates gene expression helps discern between beneficial and detrimental effects of oxidant stress, exposes a missing functional link as a marker, and yields a novel target for lung cancer.

Base Excision Repair Gene Polymorphisms and Wilms Tumor Susceptibility

Base excision repair (BER) is the main mechanism to repair endogenous DNA lesions caused by reactive oxygen species. BER deficiency is linked with cancer susceptibility and premature aging. Single nucleotide polymorphisms (SNPs) within BER genes have been implicated in various human malignancies. Nevertheless, a comprehensive investigation of their association with Wilms tumor susceptibility is lacking. In this study, 145 cases and 531 sex and age-matched healthy controls were recruited. We systematically genotyped 18 potentially functional SNPs in six core BER pathway genes, using a candidate SNP approach. Logistic regression was employed to evaluate odds ratio (OR) and 95% confidence interval (CI) adjusted for age and gender. Several SNPs showed protective effects against Wilms tumor. Significant associations with Wilms tumor susceptibility were shown for hOGG1 rs1052133 (dominant: adjusted OR = 0.66, 95% CI = 0.45-0.96, P = .030), FEN1 rs174538 (dominant: adjusted OR = 0.66, 95% CI = 0.45-0.95, P = .027; recessive: adjusted OR = 0.54, 95% CI = 0.32-0.93 P = .027), and FEN1 rs4246215 (dominant: adjusted OR = 0.55, 95% CI = 0.38-0.80, P = .002) polymorphisms. Stratified analysis was performed by age, gender, and clinical stage. Moreover, there was evidence of functional implication of these significant SNPs suggested by online expression quantitative trait locus (eQTL) analysis. Our findings indicate that common SNPs in BER genes modify susceptibility to Wilms tumor.

Human 8-oxoguanine DNA glycosylase gene polymorphism (Ser326Cys) and cancer risk: updated meta-analysis

Genetic polymorphism of human 8-oxoguanine glycosylase 1 (hOGG1) has been reported to have a relationship with the risk of the development of various cancers. Many studies have described the influence of Ser326Cys polymorphism of the hOGG1 gene on cancer susceptibility. However, the results have remained inconclusive and controversial. Therefore, we performed a meta-analysis to more precisely determine the relationship between the hOGG1 polymorphism and the development of cancer.Electronic databases including PubMed, Embase, Google Scholar, and the Korean Studies Information Service System (KISS) were searched. The odds ratio (OR), 95% confidence interval (CI), and p value were calculated to assess the strength of the association with the risk of cancer using Comprehensive Meta-analysis software (Corporation, NJ, USA). The 127 studies including 38,757 cancer patients and 50,177 control subjects were analyzed for the meta-analysis.Our meta-analysis revealed that G allele of Ser326Cys polymorphism of the hOGG1 gene statistically increased the susceptibility of cancer (all population, OR = 1.092, 95% CI = 1.051-1.134, p < 0.001; in Asian, OR = 1.095, 95% CI = 1.048-1.145, p < 0.001; in Caucasian, OR = 1.097, 95% CI = 1.033-1.179, p = 0.002). Also, other genotype models showed significant association with cancer (p < 0.05, respectively).The present meta-analysis concluded that the G allele was associated with an increased risk of cancer. It suggested that the hOGG1 polymorphism may be a candidate marker of cancer.

Single nucleotide polymorphisms in DNA glycosylases: From function to disease

Oxidative stress is associated with a growing number of diseases that span from cancer to neurodegeneration. Most oxidatively induced DNA base lesions are repaired by the base excision repair (BER) pathway which involves the action of various DNA glycosylases. There are numerous genome wide studies attempting to associate single-nucleotide polymorphisms (SNPs) with predispositions to various types of disease; often, these common variants do not have significant alterations in their biochemical function and do not exhibit a convincing phenotype. Nevertheless several lines of evidence indicate that SNPs in DNA repair genes may modulate DNA repair capacity and contribute to risk of disease. This overview provides a convincing picture that SNPs of DNA glycosylases that remove oxidatively generated DNA lesions are susceptibility factors for a wide disease spectrum that includes besides cancer (particularly lung, breast and gastrointestinal tract), cochlear/ocular disorders, myocardial infarction and neurodegenerative disorders which can be all grouped under the umbrella of oxidative stress-related pathologies.

Association of polymorphisms hOGGI rs1052133 and hMUTYH rs3219472 with risk of nasopharyngeal carcinoma in a Chinese population

This case–control study investigates the possible relationships between the single-nucleotide polymorphisms rs1052133 in the human 8-oxoguanine DNA glycosylase 1 (hOGG1) gene and rs3219472 in the human MutY glycosylase homologue (hMUTYH) gene and the risk of nasopharyngeal carcinoma (NPC). The two polymorphisms were genotyped in 488 unrelated NPC patients and 573 cancer-free controls. Genotype GG at rs1052133 was associated with significantly lower NPC risk than genotypes GC + CC (odds ratio [OR] 0.770, 95% confidence interval [CI] 0.595–0.996, P=0.012). In subgroup analyses, subjects with genotype GG at rs1052133 were at lower risk of NPC than those with GC or CC among individuals older than 40 years (OR 0.706, 95% CI 0.524–0.950), women (OR 0.571, 95% CI 0.337–0.968), and those with no smoking history (OR 0.634, 95% CI 0.463–0.868). No significant association was seen between polymorphisms at hMUTYH rs3219472 and the risk of NPC. However, gene–gene interaction analysis showed that subjects with genotype CC at rs1052133 and genotype AA at rs3219472 (CC/AA) were at 2.887-fold higher risk of NPC than those with GG/GG, 3.183-fold higher risk than those with GG/GA, and 3.392-fold higher risk than those with GG/AA. Our results suggest that hOGG1 rs1052133 polymorphism may play an important role in NPC pathogenesis, especially among women, >40 years old, and those with no smoking history. The hMUTYH rs3219472 polymorphism may interact with hOGG1 rs1052133 polymorphism to influence susceptibility to NPC.

Single nucleotide polymorphisms (SNPs) of hOGG1 and XRCC1 DNA repair genes and the risk of ovarian cancer in Polish women

The aim of this study was to determine single nucleotide polymorphisms in hOGG1 (Ser326Cys (rs13181)) and XRCC1 (Arg194Trp (rs1799782)) genes, respectively, and to identify the correlation between them and the overall risk, grading and staging of ovarian cancer in Polish women. Our study comprised 720 patients diagnosed with ovarian cancer and 720 healthy controls. The genotype analysis of hOGG1 and XRCC1 polymorphisms was performed using polymerase chain reaction (PCR)-based restriction fragment length polymorphism (PCR-RFLP). Odds ratios (OR) and 95 % confidence intervals (CI) for each genotype and allele were calculated. Results revealed an association between hOGG1 Ser326Cys polymorphism and the incidence of ovarian cancer. Variant Cys allele of hOGG1 increased the overall cancer risk (OR 2.89; 95 % CI 2.47-3.38; p < .0001). Moreover, ovarian cancer grading remained in a relationship with both analysed polymorphisms; G1 tumours presented increased frequencies of hOGG1 Cys/Cys homozygotes (OR 18.33; 95 % CI 9.38-35.81; p < .0001) and XRCC1 Trp/Trp homozygotes (OR 20.50; 95 % CI 10.17-41.32; p < .0001). Furthermore, G1 ovarian cancers displayed an overrepresentation of Cys and Trp allele. In conclusion, hOGG1 Ser326Cys and XRCC1 Arg194Trp polymorphisms may be regarded as risk factors of ovarian cancer.

The association between NQO1 Pro187Ser polymorphism and bladder cancer susceptibility: a meta-analysis of 15 studies

NAD(P)H

quinone oxidoreductase 1 (NQO1), an obligate two-electron reductase, plays an important role in reducing reactive quinones to less reactive and less toxic hydroquinones. Genetic variations in NQO1 gene that impede its enzyme function may be considered as putative risk factor for cancer. Numerous studies have been performed to investigate the association between NQO1 Pro187Ser polymorphism and bladder cancer risk; nevertheless, the results remain controversial.

METHODS

We indentified eligible publications from PubMed, Embase and CBM databases. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were used to access the strength of the associations. False-positive report probability (FPRP) analysis was also performed for all statistically significant findings.

RESULTS

We collected a total of 15 studies including 4298 cases and 4275 controls in the final meta-analysis. Overall, the NQO1 187Ser carriers were associated with an increased bladder cancer risk (homozygous: OR = 1.43, 95% CI = 1.08-1.90; recessive: OR = 1.33, 95% CI = 1.03-1.72; dominant: OR = 1.19, 95% CI = 1.04-1.37, and allele comparing: OR = 1.18, 95% CI = 1.06-1.33). Stratification analyses showed a statistically significant association among Asians (homozygous: OR = 1.82, 95% CI = 1.39-2.38; recessive: OR = 1.52, 95% CI = 1.20-1.93, dominant: OR = 1.40, 95% CI = 1.05-1.88, and allele comparing: OR = 1.35, 95% CI = 1.15-1.58), never smokers (homozygous: OR = 2.30, 95% CI = 1.14-4.65; heterozygous: OR = 2.26, 95% CI = 1.43-3.56; dominant model: OR = 1.59, 95% CI = 1.14-2.21, and allele comparing: OR = 1.72, 95% CI = 1.27-2.33), hospital-based studies (homozygous: OR = 1.46, 95% CI = 1.09-1.94; recessive: OR = 1.32, 95% CI = 1.02-1.69; dominant: OR = 1.28, 95% CI = 1.05-1.56, and allele comparing: OR = 1.24, 95% CI = 1.07-1.43), studies with genotyping performed by PCR-RFLP under all genetic models, and studies with minor allele frequency >0.30 (homozygous: OR = 1.69, 95% CI = 1.25-2.27; recessive: OR = 1.46, 95% CI = 1.10-1.95, and allele comparing: OR = 1.25, 95% CI = 1.04-1.51), respectively.

CONCLUSIONS

Despite some limitations, our meta-analysis provides sufficient evidence that NQO1 Pro187Ser polymorphism may contribute to bladder cancer risk. These findings need further validation in well-designed prospective studies with larger sample size and different ethnicities, especially for Asians.

The association between RAD23B Ala249Val polymorphism and cancer susceptibility: evidence from a meta-analysis

Background

A number of studies have investigated associations of genetic variation in RAD23B Ala249Val (rs1805329 C>T) with cancer susceptibility; however, the findings are inconsistent. We performed a meta-analysis to acquire a more precise estimation of the relationship.

Method

We searched literatures from PubMed, Embase and Web of Science. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to estimate the association between Ala249Val polymorphism and cancer risk.

Results

A total of 23 studies consisting of 10837 cases and 13971 controls were included in this meta-analysis. Overall, no significant associations were found between RAD23B Ala249Val polymorphism and cancer risk (Val/Val vs. Ala/Ala: OR = 0.97, 95% CI = 0.75–1.25; Ala/Val vs. Ala/Ala: OR = 1.08, 95% CI = 0.96–1.22; recessive model: OR = 0.93, 95% CI = 0.76–1.14 and dominant model: OR = 1.07, 95% CI = 0.94–1.20). We did not find any significant associations in the further stratification analyses by cancer type, ethnicity and source of control.

Conclusions

Despite some limitations, this meta-analysis indicates that it is unlikely that the RAD23B 249Val/Val polymorphism may contribute to the individual susceptibility to cancer risk. However, further advanced designed studies with larger sample size and different ethnicities should be conducted to confirm our results.