Significant Association Between XRCC1 Expression and Its rs25487 Polymorphism and Radiotherapy-Related Cancer Prognosis

Background/Aims

XRCC1 (X-ray repair cross-complementing protein 1) expression and its single nucleotide polymorphism XRCC1 rs25487 (G>A) may be related to radiotherapy-related cancer prognosis or radiation-induced side effects. However, this association is controversial. We performed a bioinformatic analysis and a meta-analysis to obtain comprehensive results.

Results

Sixty nine articles with 10232 patients and 17 TCGA data sets with 2705 patients were included in the analysis. We observed that high XRCC1 expression was associated with an increased risk of minor treatment response and poor overall survival, XRCC1 rs25487 was associated with reduced risk of minor treatment response in esophageal cancer and an increased risk of high-grade side effects in head and neck cancer.

Conclusion

The results suggest that XRCC1 expression and rs25487 polymorphism are prognostic factors for patients receiving radiotherapy-related treatment. Considering the insufficient treatment parameters provided and the various sample sizes in most of the studies, we suggest that genetic association studies related to radiation-based treatment should include more cancer types with sufficient statistical power and more detailed clinical parameters.

Genetic variations in DNA-repair genes (XRCC1, 3, and 7) and the susceptibility to hepatocellular carcinoma in a cohort of Egyptians

Chronic hepatitis C (CHC) is a worldwide etiology of chronic hepatic insult particularly in Egypt. DNA-repair systems are responsible for maintaining genomic integrity by countering threats posed by DNA lesions. Deficiency in the repair capacity due to genetic alterations in DNA-repair genes can lead to genomic instability and increased risk of cancer development. The present work aimed at studying the possible association between XRCC1-G28152A (rs25487), XRCC3-C18067T (rs861539), and XRCC7-G6721T (rs7003908) single nucleotide polymorphisms (SNPs) and the susceptibility to hepatocellular carcinoma (HCC) in Egyptian population. The study was conducted on 100 newly diagnosed HCC patients and 100 age- and sex-matched healthy controls. Laboratory workup revealed that all HCC patients have chronic hepatitis C viral infection. Genotyping of the studied SNPs was performed by real-time PCR. The heteromutant genotype of XRCC1 (GA) conferred an almost two-fold increased risk of HCC (OR ,  2.35; 95% CI, 1.33-4.04). Regarding XRCC7, the heteromutant (TG) genotype conferred a two-fold increased risk of HCC (OR ,  2.17; 95% CI, 1.23-3.82). Coinheritance of the polymorphic genotypes of XRCC1 and 7 was significantly higher in HCC cases than controls and was associated with an 11-fold increased risk of HCC (OR , 11.66; 95% CI,  2.77-49.13). The frequency of XRCC3 polymorphic genotypes in HCC patients was close to that of the controls.

Role of DNA repair genes XRCC3 and XRCC1 in predisposition to type 2 diabetes mellitus and diabetic nephropathy

INTRODUCTION

Increasing number of experimental and clinical studies suggest a strong relationship between hyperglycemia, oxidative stress, DNA damage and diabetic nephropathy (DN). Also, epidemiologic studies remark an enhanced risk of cancer with type 2 diabetes. This research aims to assess whether the X-ray cross complementing group 3 (XRCC3) gene T241M polymorphism (rs861539) and X-ray cross complementing group 1 (XRCC1) gene A399G polymorphism (rs25487) are related with predisposition to type 2 diabetes mellitus (T2DM) and to diabetic nephropathy in Turkish population.

MATERIALS AND METHODS

Polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) was performed to identify the distribution of genotypes and frequency of alleles of T241M polymorphism of the XRCC3 gene (XRCC3 T241M) and A399G polymorphism of the XRCC1 gene (XRCC1 A399G). The study population included 238 subjects residing in Istanbul, Turkey; 116 with T2DM, 50 with DN and 72 with normal glucose metabolism.

RESULTS AND CONCLUSION

Polymorphic Gln allele of XRCC1 gene was significantly related with T2DM and DN (OR 3.09, 95% CI 1.14-8.40 and OR 3.29 95% CI 1.23-8.80, respectively) however, there was no statistical association of XRCC3 T241M with T2DM or DN. The results of this study suggest that XRCC1 399Gln polymorphism is related with an increased susceptibility to T2DM and DN in the studied Turkish population.

XRCC1 rs25487 genetic variant and TP53 mutation at codon 249 predict clinical outcomes of hepatitis B virus-related hepatocellular carcinoma after hepatectomy: A cohort study for 10 years' follow up

AIM

To investigate the effects of rs25487 (the DNA repair gene: x-ray repair complementing defective repair in Chinese hamster cells 1 [XRCC1]) and codon 249 mutation (TP53 gene) on clinical outcomes of post-hepatectomy hepatitis B virus (HBV)-related HCC.

METHODS

The XRCC1 rs25487 polymorphism and TP53 mutation at codon 249 of 485 hepatitis B surface antigen positive patients subjected to hepatectomy were genotyped via direct sequencing. SPSS software version 16.0 (SPSS, Chicago, IL, USA) was used to calculate survival of HCC patients according to primary end-points.

RESULTS

The presence of at least one A allele (AA/AG) of rs25487 was associated with unfavorable prognosis (P = 0.005). Moreover, A allele (AA/AG) carriers were significantly associated with high risk of vascular invasion (P = 0.025) and regional invasion (P = 0.005). Differences were not significant between mutant and wild-type TP53 cases with overall survival (adjusted P = 0.400). Among the 485 participants, patients (n = 73) carrying both the A allele (AA/AG) of rs25487 and 249Ser TP53 mutation displayed decreased overall survival, compared with patients (n = 184) with the GG genotype of rs25487 and wild-type codon 249 (adjusted P = 0.007).

CONCLUSION

Polymorphisms of rs25487 may play a potential role in survival of HBV-related hepatocellular carcinoma patients following hepatectomy. While mutation at codon 249 of TP53 is not associated with HBV-related HCC survival in this study.