Common polymorphisms in DNA repair genes may alter protein function and an individual's capacity to repair damaged DNA; deficits in repair capacity may lead to genetic instability and carcinogenesis. To establish our overall understanding of possible in vivo relationships between DNA repair polymorphisms and the development of cancer, we performed a literature review of epidemiological studies that assessed associations between such polymorphisms and risk of cancer. Thirty studies of polymorphisms in OGG1, XRCC1, ERCC1, XPC, XPD, XPF, BRCA2, and XRCC3 were identified in the April 30, 2002 MEDLINE database (National Center for Biotechnology Information. PubMed Database: http://www.ncbi.nlm.nih.gov/entrez). These studies focused on adult glioma, bladder cancer, breast cancer, esophageal cancer, lung cancer, prostate cancer, skin cancer (melanoma and nonmelanoma), squamous cell carcinoma of the head and neck, and stomach cancer. We found that a small proportion of the published studies were large and population-based. Nonetheless, published data were consistent with associations between: (a) the OGG1 S326C variant and increased risk of various types of cancer; (b) the XRCC1 R194W variant and reduced risk of various types of cancer; and (c) the BRCA2 N372H variant and increased risk of breast cancer. Suggestive results were seen for polymorphisms in other genes; however, small sample sizes may have contributed to false-positive or false-negative findings. We conclude that large, well-designed studies of common polymorphisms in DNA repair genes are needed. Such studies may benefit from analysis of multiple genes or polymorphisms and from the consideration of relevant exposures that may influence the likelihood of cancer in the presence of reduced DNA repair capacity.

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Polymorphisms in DNA repair genes and associations with cancer risk.

It has been estimated by various authorities that about one-third of cancers in Western high-income societies are attributable to factors relating to food, nutrition and physical activity. Identifying with confidence specific associations between dietary patterns, foods, body composition or individual nutrients is not simple because of the long latent period for cancer development, its complex pathogenesis and the challenge of characterising the multidimensional aspects of diet and activity over a lifetime. Reliable conclusions must therefore be drawn not only from randomised controlled trials but from a variety of methodological approaches, judged within a classic framework for inferring causality. Using a newly-developed method with a protocol for standardising the literature search and for analysis and display of the evidence, nine independent academic centres have conducted systematic reviews addressing the causal associations between food, nutrition and physical activity and risk of development of seventeen cancers, as well as of weight gain and obesity. A review has also examined the efficacy of such interventions in subjects with cancer. The reviews have been assessed by an independent Panel of twenty-one international experts who drew conclusions with grades of confidence in the causality of associations and made recommendations. Recommendations are given as public health goals as well as for individuals.

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The second World Cancer Research Fund/American Institute for Cancer Research expert report. Food, nutrition, physical activity, and the prevention of cancer: a global perspective.

https://www.gastrojournal.org/article/S0016-5085(17)36039-0/pdf

Epidemiology of Esophageal Squamous Cell Carcinoma.

Genetic variations in DNA repair genes are thought to modulate DNA repair capacity and are suggested to be related to cancer risk. However, epidemiologic findings have been inconsistent. The authors conducted meta-analyses of associations between genes in the base excision repair pathway and cancer risk, focusing on three key genes: 8-oxoguanine DNA glycosylase (OGG1), apurinic/apyrimidinic endonuclease (APE1/APEX1), and x-ray repair cross-complementing group 1 (XRCC1). They found increased lung cancer risk among subjects carrying the OGG1 Cys/Cys genotype (odds ratio (OR) = 1.24, 95% confidence interval (CI): 1.01, 1.53), using 3,253 cases and 3,371 controls from seven studies; this is consistent with experimental evidence that this isoform exhibits decreased activity. They found a protective effect of the XRCC1 194Trp allele for tobacco-related cancers (OR = 0.86, 95% CI: 0.77, 0.95), using 4,895 cases and 5,977 controls from 16 studies; this is compatible with evidence of lower mutagen sensitivity for this allele. The XRCC1 399Gln/399Gln genotype was associated with increased risk of tobacco-related cancers among light smokers (OR = 1.38, 95% CI: 0.99, 1.94) but decreased risk among heavy smokers (OR = 0.71, 95% CI: 0.51, 0.99), suggesting effect modification by tobacco smoking. There was no association between cancer risk and the APE1/APEX1 Asp148Glu and XRCC1 Arg280His polymorphisms. Recommendations for future studies include pooling of individual data to facilitate evaluation of multigenic effects and detailed analysis of effect modification by environmental exposure.

Genetic Polymorphisms in the Base Excision Repair Pathway and Cancer Risk: A HuGE Review

Results. The incidence rate of significant non-cardiac occlusive stenotic lesions in patients with coronary artery disease (CAD), who had to undergo CABG, was 15,84 %. Simultaneous revascularization of coronary and non-coronary arteries was performed in 2,46 % of patients with CAD and PolyVD and multi-stage surgical proced ures were chosen in other cases. Conclusions. The outcomes of CAD surgical treatment were improved in this group of patients due to the implementation of a mul-

Федеральное государственное бюджетное учреждение «Научно-исследовательский институт комплексных проблем сердечно-сосудистых заболеваний» Сибирского отделения Российской академии медицинских наук, Кемерово, Россия

A variety of environmental factors were identified to be associated with the risk of esophageal cancer. The variation in capacity of DNA repair might influence environmental chemical-associated carcinogenesis. We hypothesized that the polymorphic XRCC1 genes might modify cancer susceptibility of the esophagus. To investigate the effect of XRCC1 genetic polymorphisms on codons 194, 280 and 399, we evaluated data from 105 patients of esophageal squamous cell carcinoma and 264 healthy controls, matching with age (±3 years), gender and ethnicity. The distribution of the 3 genotypes were not significantly different among patients and controls. However, among alcohol drinkers, the XRCC1399 Arg/Arg genotype was more frequently found in patients with esophageal cancer. After adjustment with other environmental confounders, the OR for the genotype of XRCC1399 Arg/Arg was 2.78 (95% CI =1.15–6.67) as compared with the XRCC1399Arg/Gln and XRCC1399Gln/Gln genotypes in the alcohol drinkers. Similar trends were observed among cigarette smokers and areca chewers. However, they did not reach a statistical significance. Our findings suggest that the polymorphic XRCC1 genes might modify the risk of alcohol-associated esophageal cancers. © 2001 Wiley-Liss, Inc.

Genetic polymorphisms of XRCC1 and risk of the esophageal cancer.

Among 104 cases of squamous-cell oesophageal carcinoma patients and 277 controls in Taiwan, after adjusting for cigarette smoking, alcohol consumption, and other confounders, we found that subjects who chewed from 1 to 495 betel-year and more than 495 betel-years (about 20 betel quid per day for 20 years) had 3.6-fold (95% Cl = 1.3-10.1) and 9.2-fold risk (95% Cl = 1.8-46.7), respectively, of developing oesophageal cancer, compared to those who did not chew betel.

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Risk of betel chewing for oesophageal cancer in Taiwan.

Esophageal squamous cell carcinoma (ESCC) is a frequently recurrent deadly cancer for which no efficient targeted drug exists. AXL is an adverse prognostic factor in some cancers. Strong clinical evidence to support the prognostic role of AXL in ESCC is lacking. A total of 116 patients diagnosed with operable primary ESCC were enrolled. Both AXL and HER2 expression were detected by immunohistochemistry (IHC) in esophageal tissue and were correlated with the clinical outcome of patients. The efficacy of the AXL targeted drug foretinib was also evaluated in ESCC cells. Expression of AXL was found in about 80 % of ESCC tissue, and was significantly correlated with progression of tumor (P<0.001), increased risk of death (Hazard ratio HR [95 % CI=2.09[1.09-4.04], P=0.028], and distant metastasis (odds ratio OR [95 %CI]=3.96 (1.16-13.60), P=0.029). The adverse clinical impact of AXL was more evident when cumulatively expressed with HER2. In cell model, ESCC cells were more sensitive to AXL inhibitor foretinib than to the HER2 inhibitor lapatinib. Meanwhile, the AXL inhibitor foretinib showed a synergistic effect with HER2 inhibitors and the potential to overcome drug resistance to lapatinib. We thus concluded that AXL is a strong adverse prognostic factor for ESCC. Therapeutic agents targeting AXL have great potential to improve prognosis of ESCC patients.

The AXL receptor tyrosine kinase is associated with adverse prognosis and distant metastasis in esophageal squamous cell carcinoma.

Esophageal cancer is one of the leading causes of cancer death in the male population of Eastern Asia. In addition, esophageal squamous cell carcinoma (ESCC) is the major type of esophageal cancer among the world. Owing to the poor overall 5-year survival rate, novel effective treatment strategies are needed. MicroRNAs are important gene regulators that are dysregulated in many cancer types. In our previous study, we applied next-generation sequencing to demonstrate that miR-338-5p was downregulated in the tumor tissue of patients with versus without recurrence. In this study, we further studied the roles of miR-338-5p in ESCC. The expression of endogenous miR-338-5p was at lower levels in ESCC cells compared with normal cells. Functional assays showed that miR-338-5p reduced cell proliferation, colony formation, migration and cisplatin resistance in an ESCC cell line, CE-81T. Potential target genes of miR-338-5p were identified by microarray and prediction tools, and 31 genes were selected. Among these, Fermitin family homolog 2 (FERMT2) plays an oncogenic role in ESCC, so it was chosen for further study. Luciferase assays showed the direct binding between miR-338-5p and the 3' untranslated region of FERMT2. Silencing of FERMT2 inhibited cell proliferation, colony formation, migration and cisplatin resistance. Pathway analysis revealed that the integrin-linked protein kinase signaling pathway, in which FERMT2 participates, was significantly affected by a miR-338-5p mimic. Our results suggest that miR-338-5p may play an antioncogenic role in ESCC via repressing FERMT2.

miR-338-5p inhibits cell proliferation, colony formation, migration and cisplatin resistance in esophageal squamous cancer cells by targeting FERMT2.

Purpose 
To investigate the association between genetic polymorphisms of growth factor-related genes and prognosis in patients with advanced esophageal squamous cell carcinoma (ESCC).
Patients and Methods 
A total of 334 ESCC patients with advanced tumor stages (stages IIB, III and IV) were enrolled in the study. The genotypes of 14 candidate single nucleotide polymorphisms (SNPs) involved in growth factor-related functions were analyzed using iPLEX Gold technology from the genomic DNA of peripheral leukocytes, and were correlated with the clinical outcome of patients. Serum levels of growth factors were examined by enzyme-linked immunosorbent assay (ELISA).
Results 
The genetic polymorphisms of EGF:rs4444903, EGF:rs2237051 and VEGF:rs2010963 showed significant associations with overall survival (OS) of advanced ESCC patients (A/A+ A/G vs. GG, [HR = 0.77, 95% CI = 0.60–0.99, P = 0.039 for rs4444903; A/G+ G/G vs. A/A, [HR = 0.74, 95% CI = 0.58–0.95, P = 0.019 for rs2237051; G/G+G/C vs. C/C, [HR] inves = 0.69, 95% CI = 0.50–0.95, P = 0.023 for rs2010963). EGFR:rs2227983 and 3 SNPs of PIK3CA also showed borderline significant correlation with OS of advanced ESCC patients (P = 0.058 for rs2227983; P = 0.069, 0.091 and 0.067 for rs6443624, rs7651265 and rs7621329 of PIK3CA respectively). According to cumulative effect analysis of multiple SNPs, patients carrying 4 unfavorable genotypes exhibited more than a 3-fold increased risk of mortality. Finally, both EGF and VEGF expression levels significantly associated with patient mortality.
Conclusion 
The genetic variants and expression levels of EGF and VEGF can serve as prognostic predictors in patients with advanced ESCC, and thus provide more information for optimizing personalized therapies for patients with ESCC.

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Pei-Wen Yang

Papers

Genetic polymorphisms of XRCC1 and risk of the esophageal cancer.

Risk of betel chewing for oesophageal cancer in Taiwan.

The AXL receptor tyrosine kinase is associated with adverse prognosis and distant metastasis in esophageal squamous cell carcinoma.

miR-338-5p inhibits cell proliferation, colony formation, migration and cisplatin resistance in esophageal squamous cancer cells by targeting FERMT2.

Genetic variants of EGF and VEGF predict prognosis of patients with advanced esophageal squamous cell carcinoma.