No association of p53 codon 72 and p21 codon 31 polymorphisms in Taiwan Chinese patients with pterygium

Both p53 codon 72 Arg/Arg and pro/Arg genotypes in glioblastoma multiforme are associated with a better prognosis in bevacizumab treatment

BACKGROUND

It has previously been shown that bevacizumab, when added to chemotherapy, improved overall survival in several cancers. In glioblastoma multiforme (GBM), bevacizumab increased progression-free survival and it is widely used for tumor recurrence, though it has failed to improve overall survival (OS) in controlled trials. However, an effective biomarker for predicting the prognosis of bevacizumab treatment has yet to be identified. This study, therefore, aimed to retrospectively analyze the polymorphisms of p53 codon 72 and the clinical characteristics of GBM specimens from Taiwanese patients.

METHODS

The polymorphisms of p53 codon 72 in 99 patients with GBM treated at Taichung Veterans General Hospital in Taiwan from 2007 to 2017 were analyzed using direct DNA sequencing and PCR-RFLP analysis.

RESULTS

We found that among these GBM patients, the distribution of codon 72 polymorphisms was 28.3% for proline homozygotes (Pro/Pro), 38.4% for arginine homozygotes (Arg/Arg), and 33.3% for proline/arginine heterozygotes (Pro/Arg). Although the polymorphisms of p53 codon 72 were not directly associated with the overall survival of GBM, both the Arg/Arg and Arg/Pro genotypes were associated with significant benefits in terms of overall survival in patients treated with CCRT plus bevacizumab compared to patients treated with CCRT alone.

CONCLUSIONS

This pilot study suggests that both the Arg/Arg and Arg/Pro genotypes of p53 codon 72 polymorphism may have value as independent prognostic or predictive parameters for bevacizumab treatment response and failure. Relatedly, the results of the study further demonstrate the utility of stratifying GBM patients according to bevacizumab sensitivity.

XRCC1, but not APE1 and hOGG1 gene polymorphisms is a risk factor for pterygium

PURPOSE

Epidemiological evidence suggests that UV irradiation plays an important role in pterygium pathogenesis. UV irradiation can produce a wide range of DNA damage. The base excision repair (BER) pathway is considered the most important pathway involved in the repair of radiation-induced DNA damage. Based on previous studies, single-nucleotide polymorphisms (SNPs) in 8-oxoguanine glycosylase-1 (OGG1), X-ray repair cross-complementing-1 (XRCC1), and AP-endonuclease-1 (APE1) genes in the BER pathway have been found to affect the individual sensitivity to radiation exposure and induction of DNA damage. Therefore, we hypothesize that the genetic polymorphisms of these repair genes increase the risk of pterygium.

METHODS

XRCC1, APE1, and hOGG1 polymorphisms were studied using fluorescence-labeled Taq Man probes on 83 pterygial specimens and 206 normal controls.

RESULTS

There was a significant difference between the case and control groups in the XRCC1 genotype (p=0.038) but not in hOGG1 (p=0.383) and APE1 (p=0.898). The odds ratio of the XRCC1 A/G polymorphism was 2.592 (95% CI=1.225-5.484, p=0.013) and the G/G polymorphism was 1.212 (95% CI=0.914-1.607), compared to the A/A wild-type genotype. Moreover, individuals who carried at least one C-allele (A/G and G/G) had a 1.710 fold increased risk of developing pterygium compared to those who carried the A/A wild type genotype (OR=1.710; 95% CI: 1.015-2.882, p=0.044). The hOGG1 and APE1 polymorphisms did not have an increased odds ratio compared with the wild type.

CONCLUSIONS

XRCC1 (Arg399 Glu) is correlated with pterygium and might become a potential marker for the prediction of pterygium susceptibility.

Vascular endothelial growth factor gene 460 polymorphism is associated with pterygium formation in female patients

PURPOSE

Pterygium is composed of proliferating fibrovascular tissue, and its formation and progression require neovascularization. Vascular endothelial growth factor (VEGF) is a specific mitogen for vascular endothelial cells and is essential for neovascularization. Recently, the VEGF-460 polymorphism was reported to be associated with increased VEGF basal promoter activity and with several fibrovascular diseases, such as proliferative diabetic retinopathy, endometriosis, and chronic renal disease. Therefore, this study evaluated the potential association between pterygium formation and VEGF-460 polymorphism.

METHODS

One hundred twenty-seven pterygium patients and 102 volunteers without pterygium were enrolled in this study. Polymerase chain reaction-restriction fragment length polymorphism analysis was used to resolve the VEGF-460 genotypes of pterygium patients and normal controls.

RESULTS

There were no significant differences between pterygium and control groups in age, sex, and distribution of genotype and allelic frequency of VEGF-460 polymorphism. However, when results were stratified by sex, there were significant differences between female patients and controls in the distribution of genotype and allelic frequency of VEGF-460 polymorphism. Females who carried at least 1 C allele (C/C and C/T genotypes) had about a 2.5-fold increased risk of developing pterygium compared with those who carried the T/T genotype, and there was a significantly higher frequency of C/C and C/T genotypes in younger female patients than in older female patients. There were no differences between male patients and controls in the distribution of genotype and allelic frequency of the VEGF-460 polymorphism.

CONCLUSIONS

VEGF-460C polymorphism is associated with pterygium formation in female patients. Females who carried the C allele have increased risk of developing pterygium at a younger age.