ATM polymorphisms are associated with risk of radiation-induced pneumonitis

Synergizing the interaction of single nucleotide polymorphisms with dosiomics features to build a dual-omics model for the prediction of radiation pneumonitis

OBJECTIVE

Radiation pneumonitis (RP) is the major dose-limiting toxicity of thoracic radiotherapy. This study aimed to developed a dual-omics (single nucleotide polymorphisms, SNP and dosiomics) prediction model for symptomatic RP.

MATERIALS AND METHODS

The potential SNPs, which are of significant difference between the RP grade ≥ 3 group and the RP grade ≤ 1 group, were selected from the whole exome sequencing SNPs using the Fisher's exact test. Patients with lung cancer who received thoracic radiotherapy at our institution from 2009 to 2016 were enrolled for SNP selection and model construction. The factorization machine (FM) method was used to model the SNP epistasis effect, and to construct the RP prediction model (SNP-FM). The dosiomics features were extracted, and further selected using the minimum redundancy maximum relevance (mRMR) method. The selected dosiomics features were added to the SNP-FM model to construct the dual-omics model.

RESULTS

For SNP screening, peripheral blood samples of 28 patients with RP grade ≥ 3 and the matched 28 patients with RP grade ≤ 1 were sequenced. 81 SNPs were of significant difference (P < 0.015) and considered as potential SNPs. In addition, 21 radiation toxicity related SNPs were also included. For model construction, 400 eligible patients (including 108 RP grade ≥ 2) were enrolled. Single SNP showed no strong correlation with RP. On the other hand, the SNP-SNP interaction (epistasis effect) of 19 SNPs were modeled by the FM method, and achieved an area under the curve (AUC) of 0.76 in the testing group. In addition, 4 dosiomics features were selected and added to the model, and increased the AUC to 0.81.

CONCLUSIONS

A novel dual-omics model by synergizing the SNP epistasis effect with dosiomics features was developed. The enhanced the RP prediction suggested its promising clinical utility in identifying the patients with severe RP during thoracic radiotherapy.

DNA Repair Genetics and the Risk of Radiation Pneumonitis in Patients With Lung Cancer: A Systematic Review and Meta-analysis

AIMS

ERCC1 rs11615 and ERCC2 rs238406 single nuclear polymorphism (SNPs) are known for their association with treatment outcome, likely related to radiosensitivity of both tumor and normal tissue in patients with non-small-cell lung cancer. This study aimed to review the effect of 1) these ERCC1/2 SNPs and 2) other SNPs of DNA repair genes on radiation pneumonitis (RP) in patients with lung cancer.

MATERIALS AND METHODS

SNPs of our interest included ERCC1 rs11615 and ERCC2 rs238406 and other genes of DNA repair pathways that are functional and biologically active. DNA repair SNPs reported by at least two independent studies were pooled for meta-analysis. The study endpoint was radiation pneumonitis (RP) after radiotherapy. Recessive, dominant, homozygous, heterozygous, and allelic genotype models were used where appropriate.

RESULTS

A total of 16 studies (3080 patients) were identified from the systematic review and 12 studies (2090 patients) on 11 SNPs were included in the meta-analysis. The SNPs were ATM rs189037, ATM rs373759, NEIL1 rs4462560, NEIL1 rs7402844, APE1 rs1130409, XRCC3 rs861539, ERCC1 rs11615, ERCC1 rs3212986, ERCC2 rs238406, ERCC2 rs13181, and XRCC1 rs25487. ERCC1 rs11615 (236 patients) and ERCC2 rs238406 (254 patients) were not significantly associated with RP. Using the allelic model, the G allele for NEIL1 gene was significantly associated with a reduced odds of developing symptomatic (grade ≥2) RP compared to the C allele for rs7402844 (OR 0.70, 95% CI: 0.49, 0.99, P = 0.04). Similarly, the T allele for APE1 gene was significantly associated with a reduced odds of developing symptomatic (grade ≥2) RP compared to the G allele for rs1130409 (OR 0.59, 95% CI: 0.43, 0.81, P = 0.001).

CONCLUSION

Genetic variation in the DNA repair pathway genes may play a significant role in the risk of developing radiation pneumonitis in patients with lung cancer. Further studies are needed on genotypic features of DNA repair pathway genes and their association with treatment sensitivity, as such knowledge may guide personalized radiation dose prescription.

Moving the Needle Forward in Genomically-Guided Precision Radiation Treatment

Radiation treatment (RT) is a mainstay treatment for many types of cancer. Recommendations for RT and the radiation plan are individualized to each patient, taking into consideration the patient's tumor pathology, staging, anatomy, and other clinical characteristics. Information on germline mutations and somatic tumor mutations is at present rarely used to guide specific clinical decisions in RT. Many genes, such as ATM, and BRCA1/2, have been identified in the laboratory to confer radiation sensitivity. However, our understanding of the clinical significance of mutations in these genes remains limited and, as individual mutations in such genes can be rare, their impact on tumor response and toxicity remains unclear. Current guidelines, including those from the National Comprehensive Cancer Network (NCCN), provide limited guidance on how genetic results should be integrated into RT recommendations. With an increasing understanding of the molecular underpinning of radiation response, genomically-guided RT can inform decisions surrounding RT dose, volume, concurrent therapies, and even omission to further improve oncologic outcomes and reduce risks of toxicities. Here, we review existing evidence from laboratory, pre-clinical, and clinical studies with regard to how genetic alterations may affect radiosensitivity. We also summarize recent data from clinical trials and explore potential future directions to utilize genetic data to support clinical decision-making in developing a pathway toward personalized RT.

Somatic and germline ATM variants in non-small-cell lung cancer: Therapeutic implications

ATM is an apical kinase of the DNA damage response involved in the repair of DNA double-strand breaks. Germline ATM variants (gATM) have been associated with an increased risk of developing lung adenocarcinoma (LUAD), and approximately 9% of LUAD tumors harbor somatic ATM mutations (sATM). Biallelic carriers of pathogenic gATM exhibit a plethora of immunological abnormalities, but few studies have evaluated the contribution of immune dysfunction to lung cancer susceptibility. Indeed, little is known about the clinicopathological characteristics of lung cancer patients with sATM or gATM alterations. The introduction of targeted therapies and immunotherapies, and the increasing number of clinical trials evaluating treatment combinations, warrants a careful reexamination of the benefits and harms that different therapeutic approaches have had in lung cancer patients with sATM or gATM. This review will discuss the role of ATM in the pathogenesis of lung cancer, highlighting potential therapeutic approaches to manage ATM-deficient lung cancers.

Radiogenomics in lung cancer: Where are we?

Huge technological and biomedical advances have improved the survival and quality of life of lung cancer patients treated with radiotherapy. However, during treatment planning, a probability that the patient will experience adverse effects is assumed. Radiotoxicity is a complex entity that is largely dose-dependent but also has important intrinsic factors. One of the most studied is the genetic variants that may be associated with susceptibility to the development of adverse effects of radiotherapy. This review aims to present the current status of radiogenomics in lung cancer, integrating results obtained in association studies of SNPs (single nucleotide polymorphisms) related to radiotherapy toxicities. We conclude that despite numerous publications in this field, methodologies and endpoints vary greatly, making comparisons between studies difficult. Analyzing SNPs from the candidate gene approach, together with the study in cohorts limited by the sample size, has complicated the possibility of having validated results. All this delays the incorporation of genetic biomarkers in predictive models for clinical application. Thus, from all analysed SNPs, only 12 have great potential as esophagitis genetic risk factors and deserve further exploration. This review highlights the efforts that have been made to date in the radiogenomic study of radiotoxicity in lung cancer.

Genomic Profiling Reveals Novel Predictive Biomarkers for Chemo-Radiotherapy Efficacy and Thoracic Toxicity in Non-Small-Cell Lung Cancer

Chemo-radiotherapy (CRT) remains the main treatment modality for non-small-cell lung cancer (NSCLC). However, its clinical efficacy is largely limited by individual variations in radio-sensitivity and radiotherapy-associated toxicity. There is an urgent need to identify genetic determinants that can explain patients’ likelihood to develop recurrence and radiotherapy-associated toxicity following CRT. In this study, we performed comprehensive genomic profiling, using a 474-cancer- and radiotherapy-related gene panel, on pretreatment biopsy samples from patients with unresectable stage III NSCLCs who underwent definitive CRT. Patients’ baseline clinical characteristics and genomic features, including tumor genetic, genomic and molecular pathway alterations, as well as single nucleotide polymorphisms (SNPs), were correlated with progression-free survival (PFS), overall survival (OS), and radiotherapy-associated pneumonitis and/or esophagitis development after CRT. A total of 122 patients were enrolled between 2014 and 2019, with 84 (69%) squamous cell carcinomas and 38 (31%) adenocarcinomas. Genetic analysis confirmed the association between the KEAP1-NRF2 pathway gene alterations and unfavorable survival outcome, and revealed alterations in FGFR family genes, MET, PTEN, and NOTCH2 as potential novel and independent risk factors of poor post-CRT survival. Combined analysis of such alterations led to improved stratification of the risk populations. In addition, patients with EGFR activating mutations or any oncogenic driver mutations exhibited improved OS. On the other hand, we also identified genetic markers in relation to radiotherapy-associated thoracic toxicity. SNPs in the DNA repair-associated XRCC5 (rs3835) and XRCC1 (rs25487) were associated with an increased risk of high-grade esophagitis and pneumonitis respectively. MTHFR (rs1801133) and NQO1 (rs1800566) were additional risk alleles related to higher susceptibility to pneumonitis and esophagitis overall. Moreover, through their roles in genome integrity and replicative fidelity, somatic alterations in ZNF217 and POLD1 might also serve as risk predictors of high-grade pneumonitis and esophagitis. Taken together, leveraging targeted next-generating sequencing, we identified a set of novel clinically applicable biomarkers that might enable prediction of survival outcomes and risk of radiotherapy-associated thoracic toxicities. Our findings highlight the value of pre-treatment genetic testing to better inform CRT outcomes and clinical actions in stage III unresectable NSCLCs.

Genetic susceptibility to patient-reported xerostomia among long-term oropharyngeal cancer survivors

Genetic susceptibility for xerostomia, a common sequela of radiotherapy and chemoradiotherapy for head and neck cancer, is unknown. Therefore, to identify genetic variants associated with moderate to severe xerostomia, we conducted a GWAS of 359 long-term oropharyngeal cancer (OPC) survivors using 579,956 autosomal SNPs. Patient-reported cancer treatment-related xerostomia was assessed using the MD Anderson Symptom Inventory. Patient response was dichotomized as moderate to severe or none to mild symptoms. In our study, 39.2% of OPC survivors reported moderate to severe xerostomia. Our GWAS identified eight SNPs suggestively associated with higher risk of moderate to severe xerostomia in six genomic regions (2p13.3, rs6546481, Minor Allele (MA) = A, ANTXR1, P = 4.3 × 10-7; 5p13.2-p13.1, rs16903936, MA = G, EGFLAM, P = 5.1 × 10-6; 4q21.1, rs10518156, MA = G, SHROOM3, P = 7.1 × 10-6; 19q13.42, rs11882068, MA = G, NLRP9, P = 1.7 × 10-5; 12q24.33, rs4760542, MA = G, GLT1D1, P = 1.8 × 10-5; and 3q27.3, rs11714564, MA = G, RTP1, P = 2.9 × 10-5. Seven SNPs were associated with lower risk of moderate to severe xerostomia, of which only one mapped to specific genomic region (15q21.3, rs4776140, MA = G, LOC105370826, a ncRNA class RNA gene, P = 1.5 × 10-5). Although our small exploratory study did not reach genome-wide statistical significance, our study provides, for the first time, preliminary evidence of genetic susceptibility to xerostomia. Further studies are needed to elucidate the role of genetic susceptibility to xerostomia.

ATM and TP53 Polymorphisms Modified Susceptibility to Radiation-Induced Lens Opacity in Natural High Background Radiation Area, China

Purpose: A population-based case-control study was conducted in Yangjiang and Enping areas in South China to assess whether the risk of lens opacity induced by natural high background radiation exposure is modulated by polymorphisms of ATM and TP53.Materials and methods: A total of 133 cases who were diagnosed with cortical and posterior subcapsular (PSC) opacity were recruited, and 419 healthy controls were selected through counter-matching in terms of radiation status. Genomic DNA from all the participants was genotyped with the Illumina platform for four single nucleotide polymorphisms of ATM (rs189037, rs373759, and rs4585) and TP53 (rs1042522). The cumulative lens dose received during the entire life was estimated based on annual indoor and outdoor radiation doses and gender- and age-specific occupancy factors. Non-conditional logistic regression was performed to calculate odds ratio (OR) and 95% confidence intervals (95% CI).Results: ATM rs189037 and TP53 rs1042522 were significantly related to cortical and PSC opacity. The risk of opacity was higher when individuals carried the A allele of ATM rs189037 and C allele of TP53 rs1042522, compared with GG genotype. ATM rs189037 A allele carriers (AG/AA) and TP53 rs1042522 C allele carriers (CG/CC) combined with a cumulative lens dose of 100 mGy or higher showed statistically significant opacity risks (OR =5.51, 95% CI: 1.47-20.66; OR =2.69, 95% CI: 1.10-6.60).Conclusion: The A allele of ATM rs189037 and C allele of TP53 rs1042522 increase the risk of lens opacity induced by radiation. These polymorphisms in ATM and TP53 might modify the risk of cortical and PSC opacity induced by chronic and prolonged low-dose radiation.

Modeling the risk of radiation pneumonitis in esophageal squamous cell carcinoma treated with definitive chemoradiotherapy

BACKGROUND

To develop and validate a nomogram for the prediction of symptomatic radiation pneumonitis (RP) in patients with esophageal squamous cell carcinoma (ESCC) who received definitive concurrent chemoradiotherapy.

METHODS

Clinical factors, dose-volume histogram parameters, and pulmonary function parameters were collected from 402 ESCC patients between 2010 and 2017, including 321 patients in the primary cohort and 81 in the validation cohort. The end-point was the occurrence of symptomatic RP (grade ≥ 2) within the first 12 months after radiotherapy. Univariate and multivariate logistic regression analyses were applied to evaluate the predictive value of each factor for RP. A prediction model was generated in the primary cohort, which was internally validated to assess its performance.

RESULTS

In the primary cohort, 31 patients (9.7%) experienced symptomatic RP. Based on logistic regression model, patients with larger planning target volumes (PTVs) or higher lung V₂₀ had a higher predictive risk of RP, whereas the overall risk was substantially higher for three-dimensional conformal radiotherapy (3DCRT) than intensity-modulated radiotherapy. On multivariate analysis, independent predictive factors for RP were smoking history (P = 0.035), radiotherapy modality (P < 0.001), PTV (P = 0.039), and lung V₂₀ (P < 0.001), which were incorporated into the nomogram. The areas under the receiver operating characteristic curve of the nomogram in the primary and validation cohorts were 0.772 and 0.900, respectively, which were superior to each predictor alone.

CONCLUSIONS

Non-smoking status, 3DCRT, lung V₂₀ (> 27.5%), and PTV (≥ 713.0 cc) were significantly associated with a higher risk of RP. A nomogram was built with satisfactory prediction ability.

Risk and Influencing Factors for Subsequent Primary Lung Cancer After Treatment of Breast Cancer: A Systematic Review and Two Meta-Analyses Based on Four Million Cases

INTRODUCTION

To compare the risk of developing lung cancer between patients with breast cancer and the general population and explore the risk factors for the development of primary lung cancer after treatment for breast cancer.

METHODS

The PubMed, EMBASE, and Web of Science databases were searched from the establishment date to October 11, 2020. Two separate meta-analyses were performed: one focused on studies reporting the risk of subsequent lung cancer after breast cancer and one focused on studies exploring the risk factors for subsequent lung cancer in patients with breast cancer. The standardized incidence ratios with 95% confidence intervals were combined to compare the risk of developing lung cancer between patients with breast cancer and the general population. The relative risks (RRs) or ORs with 95% confidence intervals were combined to assess the association of clinicopathological parameters with the risk of developing lung cancer after breast cancer. All statistical analyses were conducted by STATA 12.0.

RESULTS

A total of 15 studies involving 1,161,979 patients were eventually included in the first meta-analysis, and the pooled results indicated that female patients with breast cancer revealed a significantly higher risk of developing subsequent lung cancer (standardized incidence ratio = 1.25, p < 0.001). In addition, a total of 22 articles involving 3,090,620 patients were included in the second meta-analysis. The pooled results indicated that smoking (OR = 9.73, p < 0.001) and radiotherapy (RR = 1.40, p < 0.001) were risk factors for developing subsequent lung cancer in patients with breast cancer, and chemotherapy (RR = 0.69, p = 0.002), positive estrogen receptor status (RR = 0.93, p = 0.014) and positive progesterone receptor status (RR = 0.86, p < 0.001) were protective factors. Meanwhile, subgroup analysis based on the relative position of the breast and lung cancers (ipsilateral versus contralateral) was conducted, which indicated that radiotherapy only increased the risk of ipsilateral lung cancer in patients with breast cancer (RR = 1.27, p = 0.001).

CONCLUSIONS

Patients with breast cancer are more likely to develop lung cancer than the general population, and the risk of developing primary lung cancer after breast cancer is affected by smoking, radiotherapy, chemotherapy, estrogen receptor status and progesterone receptor status.

The association between the ERCC1/2 polymorphisms and radiotherapy efficacy in 87 patients with non-small cell lung cancer

Background

This study sought to investigate the association between the ERCC1/2 single-nucleotide polymorphisms (SNPs) and the efficacy of radiotherapy and prognosis in patients with non-small cell lung cancer (NSCLC).

Methods

We examined 6 SNPs in the ERCC1 and ERCC2 genes in 87 consecutive patients with NSCLC who were treated with definitive radiotherapy. The objective remission rates (ORR), overall survival (OS), and progressive-free survival (PFS) were assessed. A Cox regression analysis was conducted to analyze the independent factors related to death and recurrence.

Result

Patients with the G allele had better OS than patients with the A allele, and there was a statistical difference between the two groups (30.9 vs. 16.2 months; P=0.003). Patients with the AA genotype had significantly worse OS than patients with the AG or GG genotypes (6.8 vs. 19.8 vs. 30.9 months, respectively; P=0.000). The median PFS of the G allele was 18.9 months, which was significantly better than that of the A allele (P=0.040). The median PFS of patients with the GG genotype, the AG genotype, and the AA genotype was 18.9, 11.3, and 5.1 months, respectively; the difference among the three groups was statistically significant (P=0.019). Patients with the G allele also had better PFS than those with the A allele (18.9 vs. 11.3 months, P=0.040). The multivariate cox proportional hazard analysis showed that the ERCC1 gene rs11615 was an independent survival indicator [HR: 1.623, 95% confidence interval (CI): 1.018–2.591, P=0.042] but not an independent recurrence indicator (HR: 1.497, 95% CI: 0.932–2.404, P=0.095).

Conclusions

The ERCC1 rs11615 SNP may be a potential biomarker for predicting survival prognosis in Chinese NSCLC patients who have undergone definitive radiotherapy. Patients with the G allele had better OS than those with the A allele.

Low dose ionizing radiation effects on the immune system

Ionizing radiation interacts with the immune system in many ways with a multiplicity that mirrors the complexity of the immune system itself: namely the need to maintain a delicate balance between different compartments, cells and soluble factors that work collectively to protect, maintain, and restore tissue function in the face of severe challenges including radiation damage. The cytotoxic effects of high dose radiation are less relevant after low dose exposure, where subtle quantitative and functional effects predominate that may go unnoticed until late after exposure or after a second challenge reveals or exacerbates the effects. For example, low doses may permanently alter immune fitness and therefore accelerate immune senescence and pave the way for a wide spectrum of possible pathophysiological events, including early-onset of age-related degenerative disorders and cancer. By contrast, the so called low dose radiation therapy displays beneficial, anti-inflammatory and pain relieving properties in chronic inflammatory and degenerative diseases. In this review, epidemiological, clinical and experimental data regarding the effects of low-dose radiation on the homeostasis and functional integrity of immune cells will be discussed, as will be the role of immune-mediated mechanisms in the systemic manifestation of localized exposures such as inflammatory reactions. The central conclusion is that ionizing radiation fundamentally and durably reshapes the immune system. Further, the importance of discovery of immunological pathways for modifying radiation resilience amongst other research directions in this field is implied.

Radiation-induced lung injury: current evidence

Chemo-radiotherapy and systemic therapies have proven satisfactory outcomes as standard treatments for various thoracic malignancies; however, adverse pulmonary effects, like pneumonitis, can be life-threatening. Pneumonitis is caused by direct cytotoxic effect, oxidative stress, and immune-mediated injury. Radiotherapy Induced Lung Injury (RILI) encompasses two phases: an early phase known as Radiation Pneumonitis (RP), characterized by acute lung tissue inflammation as a result of exposure to radiation; and a late phase called Radiation Fibrosis (RF), a clinical syndrome that results from chronic pulmonary tissue damage. Currently, diagnoses are made by exclusion using clinical assessment and radiological findings. Pulmonary function tests have constituted a significant step in evaluating lung function status during radiotherapy and useful predictive tools to avoid complications or limit toxicity. Systemic corticosteroids are widely used to treat pneumonitis complications, but its use must be standardized, and consider in the prophylaxis setting given the fatal outcome of this adverse event. This review aims to discuss the clinicopathological features of pneumonitis and provide practical clinical recommendations for prevention, diagnosis, and management.

Chronic Lung Injury After Trimodality Therapy for Locally Advanced Non-Small Cell Lung Cancer

BACKGROUND

Trimodality therapy is a treatment option for patients with locally advanced non-small cell lung cancer (LA-NSCLC). Thoracic radiation has both early (radiation pneumonitis) and late (chronic lung injury [CLI]) adverse effects on the lung. While CLI is expected to result in various problems in long-term survivors, these manifestations have not been precisely investigated.

METHODS

We enrolled 112 LA-NSCLC patients who had received induction chemoradiotherapy followed by surgery, and then undergone follow-up computed tomography (CT) every 6 months for greater than 1 year. All chest CT images were reviewed to evaluate any injury of the pulmonary parenchyma.

RESULTS

CLI at 1 year after surgery and its progression were observed in 94 (84%) and 38 (34%) patients, respectively. Progressive lung fibrosis as the first manifestation of CLI progression was most frequent after right middle and lower lobectomy. Cavity formation was the subsequent manifestation after progressive lung fibrosis , and chronic infection was the final stage of CLI. The cumulative rate of chronic infection was 76.4% at 10 years in patients with cavity formation. Ten patients with chronic infection included 7 cases of pulmonary aspergillosis and 2 cases of cavity infections with methicillin-resistant Staphylococcus aureus or Stenotrophomonas maltophilia. Among them, 4 patients required surgical interventions including completion pneumonectomy or fenestration.

CONCLUSIONS

CLI is a common incidence after trimodality therapy for LA-NSCLC. CLI frequently results in cavity formation, which is a precursor of highly refractory chronic infections requiring surgical intervention. Appropriate management needs to be established for CLI developing after trimodality therapy.

Association between single nucleotide polymorphisms of DNA damage response pathway genes and increased risk in breast cancer

Aim: We aimed to evaluate the role of selected single nucleotide polymorphisms of DNA damage response pathway genes in breast cancer (BC). Materials & methods: In present study, 500 BC patients and 500 controls was used to estimate the frequency of single nucleotide polymorphisms of DNA damage response pathway genes. Tetra-amplification refractory mutation system-PCR technique was used for screening of the six selected polymorphisms. Results: Logistic regression analysis showed that heterozygous mutant genotype of rs1800057 (p < 0.0001) and homozygous mutant genotype of rs1801516 (p < 0.0001) was associated with significant increased risk of BC. In the ATR gene, heterozygous mutant genotype of rs2227931 (p < 0.0001) was associated with significant increased risk of BC. However, significant decreased risk of BC was found associated with heterozygous mutant genotype of rs2227928 (p < 0.0002) and homozygous mutant genotype of rs2229032 (p < 0.0001) in patients compared with controls. Conclusion: The present results showed that alteration in DNA damage response pathway gene (ATM & ATR) results in increased BC risk.

ATM rs189037 significantly increases the risk of cancer in non-smokers rather than smokers: an updated meta-analysis

Rs189037 (G>A) is an important functional variant with ataxia telangiectasia mutated (ATM) gene, which might affect ATM’s expression involvement in several human cancers. Increasing evidence reveals that smoking-related cancers have distinct molecular characteristics from non-smoking cancers. Until now, the role of ATM rs189037 in cancer risk stratified by smoking status still remains unclear. To evaluate the association between ATM rs189037 and cancer risk based on smoking status, we performed this meta-analysis by a comprehensive literature search via databases of PubMed, Embase, Web of Science and CNKI, updated till January 2019. Multivariate-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were extracted from eligible studies if available, to assess the relationship strengths. A total of seven eligible studies were included, comprising 4294 cancer patients (smokers: 1744 [40.6%]) and 4259 controls (smokers: 1418 [33.3%]). Results indicated a significant association of ATM rs189037 with cancer risk. In non-smokers, compared with GG genotype, AA genotype increased a 1.40-fold risk of overall cancer (OR = 1.40, 95% CI = 1.15–1.70, P_{heterogeneity}=0.433, I² = 0.0%). Subgroup analysis in lung cancer (LC) also exhibited a significant result (OR = 1.41, 95% CI = 1.15–1.73, P_{heterogeneity}=0.306, I² = 17.0%) only in non-smokers. However, the association was not observed in smokers, no matter for overall cancer or for LC. Our findings highlight that ATM rs189037 significantly increases cancer susceptibility in non-smokers, rather than in smokers. The association is prominent in LC.

Precision Radiotherapy and Radiation Risk Assessment: How Do We Overcome Radiogenomic Diversity?

Precision medicine is a rapidly developing area that aims to deliver targeted therapies based on individual patient characteristics. However, current radiation treatment is not yet personalized; consequently, there is a critical need for specific patient characteristics of both tumor and normal tissues to be fully incorporated into dose prescription. Furthermore, current risk assessment following environmental, occupational, or accidental exposures to radiation is based on population effects, and does not account for individual diversity underpinning radiosensitivity. The lack of personalized approaches in both radiotherapy and radiation risk assessment resulted in the current situation where a population-based model, effective dose, is being used. In this review article, to stimulate scientific discussion for precision medicine in both radiotherapy and radiation risk assessment, we propose a novel radiological concept and metric - the personalized dose and the personalized risk index - that incorporate individual physiological, lifestyle-related and genomic variations and radiosensitivity, outlining the potential clinical application for precision medicine. We also review on recent progress in both genomics and biobanking research, which is promising for providing novel insights into individual radiosensitivity, and for creating a novel conceptual framework of precision radiotherapy and radiation risk assessment.

Genetic variants of SP-D confer susceptibility to radiation pneumonitis in lung cancer patients undergoing thoracic radiation therapy

Background

Surfactant protein D (SP‐D) is an innate immunity molecule in the alveoli. However, the associations between genetic variants of SP‐D and radiation pneumonitis (RP) have never been investigated.

Methods

The Linkage disequilibrium of SP‐D and tagSNPs were analyzed by using Haploview 4.1. Eight tagSNPs were genotyped among 396 lung cancer patients who received thoracic radiation therapy with follow–up time (median [P25, P75]: 11[6, 18]) using improved multiplex ligation detection reaction (iMLDR). The associations between clinical characteristics, tagSNP alleles, genotypes, haplotypes and onset time of grade ≥2 or ≥3 RP were evaluated by using univariate and multivariate Cox proportional hazard regression model.

Results

Three tagSNPs of SP‐D (rs1998374, rs911887 and rs2255326) were significantly associated with grade ≥2 RP in multivariate analysis with multiple testing (Q test). The rs199874 had a protective effect for grade ≥2 RP in the dominant model (Hazard ratio (HR), 0.575; 95% confidence interval (CI), 0.378‐0.875). The homozygous mutant genotype for rs911887 had risk effect for grade ≥2 RP (HR, 2.209; 95% CI, 1.251‐3.902). The A mutant allele of rs2255326 also showed an elevated risk for grade ≥2 RP (HR, 1.777; 95% CI, 1.283‐2.461) and this risk effect was still significant in the recessive genetic model (HR, 3.320; 95% CI, 1.659‐6.644) and dominant genetic model (HR, 1.773; 95% CI, 1.166‐2.696). Compared to the lung cancer patients bearing the most common haplotype C‐G‐T, the patients bearing the haplotype T‐A‐C (rs1998374‐rs2255326‐rs911887) showed a significant risk of both grade ≥2 RP (HR, 1.885; 95% CI, 1.284‐2.765) and grade ≥3 RP (HR, 2.256; 95% CI, 1.248‐4.080).

Conclusions

Genetic variants of SP‐D were associated with risk of RP development in lung cancer patients receiving thoracic radiotherapy.

Radiation Pneumonitis after Intensity-Modulated Radiotherapy for Esophageal Cancer: Institutional Data and a Systematic Review

Radiation pneumonitis (RP) is a serious complication that can occur after thoracic radiotherapy. The goal of this study is to investigate the incidence of RP after radiochemotherapy with intensity modulated radiotherapy (IMRT) in patients with esophageal cancer and correlate this with dose volume histogram (DVH) related parameters. For this purpose, the clinical course of 73 patients was evaluated and irradiation doses to the lungs were extracted from radiotherapy treatment plans. Furthermore, a systematic review on this topic was conducted across PubMed. In our institutional cohort, Common Terminology Criteria for Adverse Events (CTCAE) grade II or higher RP occurred in four patients (5.5%). The systematic review identified 493 titles of which 19 studies reporting 874 patients qualified for the final analysis. No grade IV or V RP after radiochemotherapy with IMRT for esophageal cancer was reported in the screened literature. Grade II or higher RP is reported in 6.6% of the patients. A higher incidence can be seen with increasing values for lung V20. In conclusion, our institutional data and the literature consistently show a low incidence of symptomatic RP after radiochemotherapy in patients with esophageal cancer treated with IMRT. However, efforts should be made to keep the lung V20 below 23% and specific caution is warranted in patients with pre-existing lung conditions.

A review of radiation genomics: integrating patient radiation response with genomics for personalised and targeted radiation therapy

Background

The success of radiation therapy for cancer patients is dependent on the ability to deliver a total tumouricidal radiation dose capable of eradicating all cancer cells within the clinical target volume, however, the radiation dose tolerance of the surrounding healthy tissues becomes the main dose-limiting factor. The normal tissue adverse effects following radiotherapy are common and significantly impact the quality of life of patients. The likelihood of developing these adverse effects following radiotherapy cannot be predicted based only on the radiation treatment parameters. However, there is evidence to suggest that some common genetic variants are associated with radiotherapy response and the risk of developing adverse effects. Radiation genomics is a field that has evolved in recent years investigating the association between patient genomic data and the response to radiation therapy. This field aims to identify genetic markers that are linked to individual radiosensitivity with the potential to predict the risk of developing adverse effects due to radiotherapy using patient genomic information. It also aims to determine the relative radioresponse of patients using their genetic information for the potential prediction of patient radiation treatment response.

Methods and materials

This paper reports on a review of recent studies in the field of radiation genomics investigating the association between genomic data and patients response to radiation therapy, including the investigation of the role of genetic variants on an individual’s predisposition to enhanced radiotherapy radiosensitivity or radioresponse.

Conclusion

The potential for early prediction of treatment response and patient outcome is critical in cancer patients to make decisions regarding continuation, escalation, discontinuation, and/or change in treatment options to maximise patient survival while minimising adverse effects and maintaining patients’ quality of life.

Functional Evaluation of ZNF350 Missense Genetic Variants Associated with Breast Cancer Susceptibility

ZNF350, a BRCA1-interacting protein, could mediate BRCA1-induced sequence-specific transcriptional repression of several genes, including GADD45α. As a potential breast cancer susceptibility gene, single nucleotide polymorphisms (SNPs), especially missense SNPs, may influence the transcriptional repression of its target tumor suppressor genes and individuals' breast cancer risk. Using the gene-based haplotype-tagging SNPs strategy, we evaluated the association between six ZNF350 polymorphisms and breast cancer risk in a case-control set from a northern Chinese population. The impact of ZNF350 variations on transcriptional repression of GADD45α was also examined. It was found that ZNF350 rs2278420 (L66P) and rs2278415 (S501R) missense genetic variants are in complete linkage disequilibrium and have a significant impact on inter-individual susceptibility to breast cancer. Additionally, ZNF350 GGCGT or GGCGC haplotype is also associated with a significantly increased breast cancer risk compared with the GGCAC haplotype. ZNF350 L66P variant modifies the risk of breast cancer not only by itself but also in a gene-environment interaction manner with age, age at menarche, menopause status, or estrogen receptor status. Interestingly, we observed that ZNF350 L66P and S501R SNPs could weaken the capability of ZNF350-mediated GADD45α transcription repression and it may be an underlying mechanism of the observed epidemiological associations. Our results highlight ZNF350 as an important gene in human mammary oncogenesis and ZNF350 missense genetic polymorphisms confer susceptibility to breast cancer.

Functional promoter rs189037 variant of ATM is associated with decrease in lung diffusing capacity after irradiation for non-small-cell lung cancer

Objective

Single-nucleotide polymorphisms (SNPs) in the ataxia telangiectasia-mutated gene ATM have been linked with pneumonitis after radiotherapy for lung cancer but have not been evaluated in terms of pulmonary function impairment. Here we investigated potential associations between SNPs in ATM and changes in diffusing capacity of the lung for carbon monoxide (DLCO) in patients with non-small-cell lung cancer (NSCLC) after radiotherapy.

Methods

From November 1998 through June 2009, 448 consecutive patients with inoperable primary NSCLC underwent definitive (≥60 Gy) radiotherapy, with or without chemotherapy. After excluding patients with a history of thoracic surgery, radiation, or lung cancer; without DNA samples available for analysis; or without pulmonary function testing within the 12 months before and the 12 months after radiotherapy, 100 patients were identified who are the subjects of this study. We genotyped two SNPs of ATM previously found to be associated with radiation-induced pneumonitis (rs189037 and rs228590) and evaluated potential correlations between these SNPs and impairment (decreases) in DLCO by using logistic regression analysis.

Results

Univariate and multivariate analyses showed that the AA genotype of ATM rs189037 was associated with decreased DLCO after definitive radiotherapy than the GG/AG genotypes [univariate coefficient, -0.122; 95% confidence interval (CI), -0.236 to -0.008; P = 0.037; and multivariate coefficient, -0.102; 95% CI, -0.198 to -0.005; P = 0.038]. No such correlations were found for rs228590 (univariate coefficient, -0.096; 95% CI, -0.208 to 0.017; P = 0.096).

Conclusions

The AA genotype of ATM rs189037 was associated with higher risk of lung injury than were the GG/AG genotypes in patients with NSCLC treated with radiotherapy. This finding should be validated prospectively with other patient populations.

Association between ATM gene polymorphisms, lung cancer susceptibility and radiation-induced pneumonitis: a meta-analysis

BACKGROUND

Previous studies have suggested that DNA double-strand break (DSB) repair is an important protective pathway after damage. The ataxia telangiectasia mutated (ATM) gene plays an important role in the DNA DSB repair pathway. DNA damage is a major cytotoxic effect that can be caused by radiation, and the ability to repair DNA after damage varies among different tissues. Impaired DNA repair pathways are associated with high sensitivity to radiation exposure. Hence, ATM gene polymorphisms are thought to influence the risk of cancer and radiation-induced pneumonitis (RP) risk in cancer patients treated with radiotherapy. However, the results of previous studies are inconsistent. We therefore conducted this comprehensive meta-analysis.

METHODS

A systematic literature search was performed in the PubMed, Embase, China National Knowledge Internet (CNKI) and Wanfang databases to identify studies that investigated the association between the ATM gene polymorphisms and both lung cancer and RP radiotherapy-treated lung cancer (the last search was conducted on Dec.10, 2015). The odds ratio (OR) and 95% confidence interval (CI) were used to investigate the strength of these relationships. Funnel plots and Begg's and Egger's tests were conducted to assess the publication bias. All analyses were performed in STATA 13.0 software.

RESULTS

Ten eligible case-control studies (4731 cases and 5142 controls) on lung cancer susceptibility and four (192 cases and 772 controls) on RP risk were included. The results of the overall and subgroup analyses indicated that in the ATM gene, the rs189037 (-111G > A, -4519G > A), rs664677 (44831C > T, 49238C > T) and rs664143 (131,717 T > G) polymorphisms were significantly associated with lung cancer susceptibility (OR = 1.21, 95% CI = 1.04-1.39, P = 0.01; OR = 1.26, 95% CI = 1.06-1.49, P = 0.01; OR = 1.43, 95% CI = 1.15-1.78, P < 0.01). Additionally, the rs189037 variant was significantly associated with RP risk (OR = 1.74, 95% CI = 1.02-2.97, P = 0.04). No publication bias was found in the funnel plots, Begg's tests or Egger's tests.

CONCLUSIONS

The results indicate that the ATM rs189037, rs664677 and rs664143 gene polymorphisms are risk factors for lung cancer, while the ATM rs189037 variant was significantly associated with RP risk.

Association of DNA repair gene polymorphisms with the risk of radiation pneumonitis in lung cancer patients

A total of 149 lung cancer patients were recruited to receive intensity modulated radiation therapy (IMRT). The association of developing radiation pneumonitis (RP) with genetic polymorphism was evaluated. The risks of four polymorphic sites in three DNA repair related genes (ERCC1, rs116615:T354C and rs3212986:C1516A; ERCC2, rs13181:A2251C; XRCC1, rs25487:A1196G) for developing grade ≥ 2 RP were assessed respectively. It was observed that ERCC1 T354C SNP had a significant effect on the development of grade ≥ 2 RP (CT/TT vs. CC, adjusted HR = 0.517, 95% CI, 0.285-0.939; adjusted P = 0.030). It is the first time demonstrating that CT/TT genotype of ERCC1 354 was significantly associated with lower RP risk after radio therapy.

Germline Mutations in DNA Repair Genes in Lung Adenocarcinoma

INTRODUCTION

Although lung cancer is generally thought to be environmentally provoked, anecdotal familial clustering has been reported, suggesting that there may be genetic susceptibility factors. We systematically tested whether germline mutations in eight candidate genes may be risk factors for lung adenocarcinoma.

METHODS

We studied lung adenocarcinoma cases for which germline sequence data had been generated as part of The Cancer Genome Atlas project but had not been previously analyzed. We selected eight genes, ATM serine/threonine kinase gene (ATM), BRCA2, DNA repair associated gene (BRCA2), checkpoint kinase 2 gene (CHEK2), EGFR, parkin RBR E3 ubiquitin protein ligase gene (PARK2), telomerase reverse transcriptase gene (TERT), tumor protein p53 gene (TP53), and Yes associated protein 1 gene (YAP1), on the basis of prior anecdotal association with lung cancer or genome-wide association studies.

RESULTS

Among 555 lung adenocarcinoma cases, we detected 14 pathogenic mutations in five genes; they occurred at a frequency of 2.5% and represented an OR of 66 (95% confidence interval: 33-125, p < 0.0001 [chi-square test]). The mutations fell most commonly in ATM (50%), followed by TP53, BRCA2, EGFR, and PARK2. Most (86%) of these variants had been reported in other familial cancer syndromes. Another 12 cases (2%) carried ultrarare variants that were predicted to be deleterious by three protein prediction programs; these most frequently involved ATM and BRCA2.

CONCLUSIONS

A subset of patients with lung adenocarcinoma, at least 2.5% to 4.5%, carry germline variants that have been linked to cancer risk in Mendelian syndromes. The genes fall most frequently in DNA repair pathways. Our data indicate that patients with lung adenocarcinoma, similar to other solid tumors, include a subset of patients with inherited susceptibility.

Outcomes and complications of radiation therapy in patients with familial adenomatous polyposis

BACKGROUND

The outcomes, complications, and rates of secondary malignancies from radiation therapy (RT) are not known for patients with familial adenomatous polyposis (FAP).

METHODS

We queried the Hereditary Gastrointestinal Cancer Registry (HGCR) for patients with FAP who received RT. Outcomes assessed included acute and late treatment toxicity and secondary malignancies.

RESULTS

We identified 15 patients undergoing 18 treatment courses. Median follow-up was 3.1 years after RT. Treated sites included rectal cancer, desmoid, prostate cancer, breast cancer, melanoma, medulloblastoma, gastric cancer, and glioma. Secondary tumors occurred in two patients: a medulloblastoma was diagnosed in a patient treated for glioma, and a desmoid tumor was diagnosed in a patient treated for rectal cancer. All nine patients treated with intra-abdominal or pelvic RT had prior prophylactic proctocolectomies, yet only one patient experienced grade 3 gastrointestinal toxicity. Common Terminology Criteria for Adverse Events version 4 (CTCAE v4) toxicities were grade 1 in seven treatment courses (39%), grade 2 in five courses (28%), and grade 3 in two courses (11%).

CONCLUSIONS

In this cohort, RT was well tolerated with adverse effects comparable with non-FAP patients. Secondary in-field tumors occurred in 2 of 15 patients and their increased risk in this cohort was likely due to prior predilection from FAP itself, although an increased role of RT cannot be ruled out.

Targeting DNA Damage Response in the Radio(Chemo)therapy of Non-Small Cell Lung Cancer

Lung cancer is the leading cause of cancer death worldwide due to its high incidence and mortality. As the most common lung cancer, non-small cell lung cancer (NSCLC) is a terrible threat to human health. Despite improvements in diagnosis and combined treatments including surgical resection, radiotherapy and chemotherapy, the overall survival for NSCLC patients still remains poor. DNA damage is considered to be the primary cause of lung cancer development and is normally recognized and repaired by the intrinsic DNA damage response machinery. The role of DNA repair pathways in radio(chemo)therapy-resistant cancers has become an area of significant interest in the clinical setting. Meanwhile, some studies have proved that genetic and epigenetic factors can alter the DNA damage response and repair, which results in changes of the radiation and chemotherapy curative effect in NSCLC. In this review, we focus on the effect of genetic polymorphisms and epigenetic factors such as miRNA regulation and lncRNA regulation participating in DNA damage repair in response to radio(chemo)therapy in NSCLC. These may provide novel information on the radio(chemo)therapy of NSCLC based on the individual DNA damage response.

Effect of ATM-111 (G>A) Polymorphism on Cancer Risk: A Meta-Analysis

OBJECTIVE

To assess the relationship between the ataxia telangiectasia mutated (ATM) gene-111 (G>A) polymorphism and cancer risk.

METHODS

The PubMed, EMBASE, Web of Science, and China National Knowledge Infrastructure databases were searched comprehensively. A total of 16 case-control studies with 12,273 cases and 13,046 controls were included in this meta-analysis; 12 of them were from the Chinese population. Five studies assessed smoking effects, including 3038 smokers and 1003 nonsmokers. Odds ratio (OR) was determined by using a genetic model-free approach. Heterogeneity was quantified by I(2) statistics. Publication bias was also evaluated.

RESULTS

The recessive model (AA vs. AG + GG) was suggested as the most appropriate genetic model. After elimination of heterogeneity, it was found that the ATM-111 (G>A) AA genotype is significantly associated with increased susceptibility to overall cancer risk in a fixed effects model (OR = 1.09; 95% CI = 1.03-1.15; p < 0.01; I(2) < 0.01). In the subgroup analysis, the result of pooled analyses among the Chinese population revealed similar associations (OR = 1.12; 95% CI = 1.04-1.22; p < 0.01; I(2) < 0.01). As for specific cancer analysis, an increase was correlated with lung cancer risk (OR = 1.12; 95% CI = 1.01-1.24; p = 0.03) and breast cancer risk (OR = 1.08; 95% CI = 1.00-1.16; p = 0.05). In addition, a stronger association was found among nonsmokers (OR = 1.31; 95% CI = 1.13-1.52; p < 0.01).

CONCLUSION

This meta-analysis suggests that AA genotype of the ATM-111 gene (G>A) may be a risk factor for breast cancer and lung cancer, especially among nonsmokers, within the Chinese population.

Association between Genetic Variants in DNA Double-Strand Break Repair Pathways and Risk of Radiation Therapy-Induced Pneumonitis and Esophagitis in Non-Small Cell Lung Cancer

Radiation therapy (RT)-induced pneumonitis and esophagitis are commonly developed side effects in non-small cell lung cancer (NSCLC) patients treated with definitive RT. Identifying patients who are at increased risk for these toxicities would help to maximize treatment efficacy while minimizing toxicities. Here, we systematically investigated single nucleotide polymorphisms (SNPs) within double-strand break (DSB) repair pathway as potential predictive markers for radiation-induced esophagitis and pneumonitis. We genotyped 440 SNPs from 45 genes in DSB repair pathways in 250 stage I–III NSCLC patients who received definitive radiation or chemoradiation therapy, followed by internal validation in 170 additional patients. We found that 11 SNPs for esophagitis and 8 SNPs for pneumonitis showed consistent effects between discovery and validation populations (same direction of OR and reached significance in meta-analysis). Among them, rs7165790 in the BLM gene was significantly associated with decreased risk of esophagitis in both discovery (OR = 0.59, 95% CI: 0.37–0.97, p = 0.037) and validation subgroups (OR = 0.45, 95% CI: 0.22–0.94, p = 0.032). A strong cumulative effect was observed for the top SNPs, and gene-based tests revealed 12 genes significantly associated with esophagitis or pneumonitis. Our results support the notion that genetic variations within DSB repair pathway could influence the risk of developing toxicities following definitive RT in NSCLC.

Impact of single-nucleotide polymorphisms on radiation pneumonitis in cancer patients

Radiation pneumonitis (RP) is one of the most important dose-limiting toxicities in the radiotherapy of thoracic tumors, which reduces the rate of local tumor control and overall survival and severely affects the patients' quality of life. Single-nucleotide polymorphisms (SNPs) have recently attracted increasing attention as biomarkers for predicting the development of RP. SNPs in inflammation-related, DNA repair-related, stress response-related and angiogenesis-related genes were proved to be associated with RP, with different underlying mechanisms. Radiogenomics focuses on the differences in radiosensitivity caused by gene sequence variation, which may prove helpful in investigating the abovementioned associations. In this review, we aimed to investigate the associations between RP and SNPs reported in recent studies and highlight the main content and prospects of radiogenomics.

Unexpected Symptomatic Pneumonitis Following Breast Tangent Radiation: A Case Report

Symptomatic radiation pneumonitis (RP) following radiation therapy (RT) to the breast alone is very uncommon. We report a case of an 80-year-old female who presented with fatigue, exertional dyspnea, fever, and cough 11.5 weeks following adjuvant breast RT with tangent fields alone. Imaging was consistent with RP, and she responded to a tapering course of steroids.

Associations of ATM Polymorphisms With Survival in Advanced Esophageal Squamous Cell Carcinoma Patients Receiving Radiation Therapy

PURPOSE

To investigate whether single nucleotide polymorphisms (SNPs) in the ataxia telangiectasia mutated (ATM) gene are associated with survival in patients with esophageal squamous cell carcinoma (ESCC) receiving radiation therapy or chemoradiation therapy or surgery only.

METHODS AND MATERIALS

Four tagSNPs of ATM were genotyped in 412 individuals with clinical stage III or IV ESCC receiving radiation therapy or chemoradiation therapy, and in 388 individuals with stage I, II, or III ESCC treated with surgery only. Overall survival time of ESCC among different genotypes was estimated by Kaplan-Meier plot, and the significance was examined by log-rank test. The hazard ratios (HRs) and 95% confidence intervals (CIs) for death from ESCC among different genotypes were computed by a Cox proportional regression model.

RESULTS

We found 2 SNPs, rs664143 and rs664677, associated with survival time of ESCC patients receiving radiation therapy. Individuals with the rs664143A allele had poorer median survival time compared with the rs664143G allele (14.0 vs 20.0 months), with the HR for death being 1.45 (95% CI 1.12-1.89). Individuals with the rs664677C allele also had worse median survival time than those with the rs664677T allele (14.0 vs 23.5 months), with the HR of 1.57 (95% CI 1.18-2.08). Stratified analysis showed that these associations were present in both stage III and IV cancer and different radiation therapy techniques. Significant associations were also found between the SNPs and locosregional progression or progression-free survival. No association between these SNPs and survival time was detected in ESCC patients treated with surgery only.

CONCLUSION

These results suggest that the ATM polymorphisms might serve as independent biomarkers for predicting prognosis in ESCC patients receiving radiation therapy.

ATM gene single nucleotide polymorphisms predict regimen-related gastrointestinal toxicity in patients allografted after reduced conditioning

Polymorphisms of genes involved in innate and adaptive immunity have become an object of major interest in regard to hematopoietic stem cell transplantation (HSCT) complications. Regimen-related gastrointestinal toxicity (RR-GIT) is the dominant complication during the pre-engraftment period and has been linked to increased risk of graft-versus-host disease (GVHD) development. According to our hypothesis, functional variants of genes participating in DNA damage response (DDR) may have an impact on the extent of tissue damage caused by the conditioning regimen. In our single-center study, we analyzed 62 patients who underwent HSCT from HLA-identical donors after reduced conditioning. The patients were genotyped for 5 single nucleotide polymorphisms (SNPs, rs4585 T/G, rs189037 A/G, rs227092 T/G, rs228590 C/T, and rs664677 T/C) of the ATM gene-the essential member of the DDR pathways, using allele-specific matrix-assisted laser desorption/ionization, time-of-flight (MALDI-TOF) mass spectrometry assay. Because of almost absolute linkage disequilibrium observed among all 5 SNPs, association of 2 major ATM haplotypes (ATM1/ATM2) with RR-GIT and acute GVHD (aGVHD) was analyzed. Importantly, the univariate and multivariate analysis showed that patients homozygous for ATM2 haplotype (rs4585*T, rs189037*A, rs227092*T, rs228590*C, and rs664677*T) are more likely to suffer from high-grade RR-GIT than ATM1 homozygous patients. The association with aGVHD was not significant. To our knowledge, this is the first report showing the ATM gene variability in relation to RR-GIT in the allogeneic HSCT setting.

Predictive SNPs for radiation-induced damage in lung cancer patients with radiotherapy: a potential strategy to individualize treatment

In the treatment of lung cancer, radiotherapy has become one of the most important therapies, despite its sometimes unpredictable side effects. As such, identifying lung cancer patients who are at high risk of developing severe radiation-induced damage (mainly radiation pneumonitis and radiation-induced esophageal toxicity) and applying effect intervention or monitoring techniques are important. Although human diversity to a certain amount is explained by clinical and dosimetric factors, the presence of specific genetic determinants also influences the occurrence of radiation-induced damage. Here we summarize the data on mechanisms of radiation pneumonitis and radiation-induced esophageal toxicity supporting the involvement of variances of genes in the evolution of radiation-induced damage. Furthermore, the available evidence from current clinical studies of genetic polymorphisms for the prediction of radiation pneumonitis and radiation-induced esophageal toxicity is discussed. Eventually, this may help to truly individualize radiotherapy, using a personal genetic profile of the most relevant genes for each lung cancer patient.

Radiogenomics helps to achieve personalized therapy by evaluating patient responses to radiation treatment

Radiogenomics is the whole genome application of radiogenetics, which focuses on uncovering the underlying genetic causes of individual variation in sensitivity to radiation. There is a growing consensus that radiosensitivity is a complex, inherited polygenic trait, dependent on the interaction of many genes involved in multiple cell processes. An understanding of the genes involved in processes such as DNA damage response and oxidative stress response, has evolved toward examination of how genetic variants, most often, single nucleotide polymorphisms (SNPs), may influence interindividual radioresponse. Many experimental approaches, such as candidate SNP association studies, genome-wide association studies and massively parallel sequencing are being proposed to address these questions. We present a review focusing on recent advances in association studies of SNPs to radiotherapy response and discuss challenges and opportunities for further studies. We also highlight the clinical perspective of radiogenomics in the future of personalized treatment in radiation oncology.

Nondosimetric risk factors for radiation-induced lung toxicity

The decision to administer a radical course of radiotherapy (RT) is largely influenced by the dose-volume metrics of the treatment plan, but what are the patient-related and other factors that may independently increase the risk of radiation lung toxicity? Poor pulmonary function has been regarded as a risk factor and a relative contraindication for patients undergoing radical RT, but recent evidence suggests that patients with poor spirometry results may tolerate conventional or high-dose RT as well as, if not better than, patients with normal function. However, caution may need to be exercised in patients with underlying interstitial pulmonary fibrosis. Furthermore, there is emerging evidence of molecular markers of increased risk of toxicity. This review discusses patient-related risk factors other than dosimetry for radiation lung toxicity.

A polymorphism in the DNA repair domain of APEX1 is associated with the radiation-induced pneumonitis risk among lung cancer patients after radiotherapy

OBJECTIVE

To examine the association of tag single nucleotide polymorphisms (tagSNPs) (rs1130409, rs1760944, rs2307486 and rs3136817) in APEX1 with the risk of severe radiation-induced pneumonitis (RP) after radiotherapy among Han Chinese patients with lung cancer.

METHODS

A total of 168 patients with lung cancer who were receiving radiotherapy were prospectively recruited. RP was evaluated according to the Radiation Therapy Oncology Group. A case-control study was performed. The case group included patients with RP grade of ≥3, while the control group comprised patients with RP grades <3. Four tagSNPs of APEX1 were genotyped in 126 patients with complete follow-up by multi-SNaPshot® (Genesky Biotechnologies Inc., Shanghai, China) genotyping assays. RESULTS were assessed by a logistic regression model for RP risk and Mantal-Cox log-rank test for the cumulative RP probability by the genotypes.

RESULTS

rs1130409 was associated with severe RP. GT genotype of rs1130409 was significantly higher in patients with RP than in those of the control group [68.8% vs 41.8%; p = 0.025; resulting odds ratio (OR), 5.98]. Patients with lung cancer bearing the G allele had a 5.83-fold higher risk of RP than those with the wild TT genotype [OR = 5.83; 95% confidence interval (CI), 1.27-26.90; p = 0.024], and this was further confirmed by the binary regression adjusted by some confounding factors, including Karnofsky performance scale, concurrent chemotherapy-radiotherapy and lung volume receiving >30 Gy (OR = 6.96; 95% CI, 1.36-35.77; p = 0.02). rs1130409 was also associated with the time to occurrence of severe RP (p = 0.04). Three-dimensional model APEX1 protein showed that rs1130409 is located in the random coil structure corresponding to the DNA repair function region.

ADVANCES IN KNOWLEDGE

rs1130409 of APEX1 can be a predictor of RP grades ≥3 among patients with lung cancer.

Single nucleotide polymorphism in ATM gene, cooking oil fumes and lung adenocarcinoma susceptibility in Chinese female non-smokers: a case-control study

BACKGROUND

The ataxia-telangiectasia mutated (ATM) gene plays an important role in the DNA double-strand breaks repair pathway. Single nucleotide polymorphisms (SNPs) of DNA repair genes are suspected to influence the risk of lung cancer. This study aimed to investigate the association between the ATM -111G>A (rs189037) polymorphism, environmental risk factors and the risk of lung adenocarcinoma in Chinese female non-smokers.

METHODS

A hospital-based case-control study of 487 lung cancer patients and 516 matched cancer-free controls was conducted. Information concerning demographic and environmental risk factors was obtained for each case and control by a trained interviewer. After informed consent was obtained, 10 ml venous blood was collected from each subject for biomarker testing. Single nucleotide polymorphism was determined by using TaqMan method.

RESULTS

This study showed that the individuals with ATM rs189037 AA genotype were at an increased risk for lung adenocarcinoma compared with those carrying the GA or GG genotype (adjusted odds ratios (OR) 1.44, 95% confidence interval (CI) 1.02-2.02, P = 0.039). The stratified analysis suggested that increased risk associated with ATM rs189037 AA genotype in individuals who never or seldom were exposed to cooking oil fumes (adjusted OR 1.89, 95%CI 1.03-3.49, P = 0.040).

CONCLUSIONS

ATM rs189037 might be associated with the risk of lung adenocarcinoma in Chinese non-smoking females. Furthermore, ATM rs189037 AA genotype might be a risk factor of lung adenocarcinoma among female non-smokers without cooking oil fume exposure.

What's your poison? Impact of individual repair capacity on the outcomes of genotoxic therapies in cancer. Part II - information content and validity of biomarkers for individual repair capacity in the assessment of outcomes of anticancer therapy

The individual variance in the efficiency of repair of damage induced by genotoxic therapies may be an important factor in the assessment of eligibility for different anticancer treatments, the outcomes of various treatments and the therapy-associated complications, including acute and delayed toxicity and acquired drug resistance. The second part of this paper analyses the currently available information about the possibilities of using experimentally obtained knowledge about individual repair capacity for the purposes of personalised medicine and healthcare.

Genetic variants in inducible nitric oxide synthase gene are associated with the risk of radiation-induced lung injury in lung cancer patients receiving definitive thoracic radiation

BACKGROUND AND PURPOSE

Nitric oxide (NO), mainly synthesized by inducible nitric oxide synthase (NOS2) in pathological conditions, plays an important role in cytotoxicity, inflammation and fibrosis. Elevations in exhaled NO after thoracic radiation have been reported to predict radiation-induced lung injury (RILI). This study examined whether genetic variations in NOS2 gene is associated with the risk of RILI.

MATERIAL AND METHODS

A cohort of 301 patients between 2009 and 2011 were genotyped for 21 single nucleotide polymorphisms (SNPs) in the NOS2 gene by the Sequenom MassArray system. Kaplan-Meier cumulative probability was used to assess RILI risk and Cox proportional hazards analyses were performed to evaluate the effect of NOS2 genotypes on RILI.

RESULTS

Multivariate analysis found that three SNPs (rs2297518, rs1137933 and rs16949) in NOS2 were significantly associated with risk of RILI⩾2 (P value=0.001, 0.000092, 0.001, respectively) after adjusting for other covariates. Their associations were independent of radiation dose and mean lung dose. Further haplotype analysis indicated that the ATC haplotype of three SNPs is associated with reducing the risk of developing RILI.

CONCLUSION

Our results demonstrate that genetic variants of NOS2 may serve as a reliable predictor of RILI in lung cancer patients treated with thoracic radiation.

Second malignant neoplasms and cardiovascular disease following radiotherapy

Second malignant neoplasms (SMNs) and cardiovascular disease (CVD) are among the most serious and life-threatening late adverse effects experienced by the growing number of cancer survivors worldwide and are due in part to radiotherapy. The National Council on Radiation Protection and Measurements (NCRP) convened an expert scientific committee to critically and comprehensively review associations between radiotherapy and SMNs and CVD, taking into account radiobiology; genomics; treatment (i.e., radiotherapy with or without chemotherapy and other therapies); type of radiation; and quantitative considerations (i.e., dose-response relationships). Major conclusions of the NCRP include: (1) the relevance of older technologies for current risk assessment when organ-specific absorbed dose and the appropriate relative biological effectiveness are taken into account and (2) the identification of critical research needs with regard to newer radiation modalities, dose-response relationships, and genetic susceptibility. Recommendation for research priorities and infrastructural requirements include (1) long-term large-scale follow-up of extant cancer survivors and prospectively treated patients to characterize risks of SMNs and CVD in terms of radiation dose and type; (2) biological sample collection to integrate epidemiological studies with molecular and genetic evaluations; (3) investigation of interactions between radiotherapy and other potential confounding factors, such as age, sex, race, tobacco and alcohol use, dietary intake, energy balance, and other cofactors, as well as genetic susceptibility; (4) focusing on adolescent and young adult cancer survivors, given the sparse research in this population; and (5) construction of comprehensive risk prediction models for SMNs and CVD to permit the development of follow-up guidelines and prevention and intervention strategies.

XRCC3 polymorphisms are associated with the risk of developing radiation-induced late xerostomia in nasopharyngeal carcinoma patients treated with intensity modulation radiated therapy

OBJECTIVE

The incidence of radiation-induced late xerostomia varies greatly in nasopharyngeal carcinoma patients treated with radiotherapy. The single-nucleotide polymorphisms in genes involved in DNA repair and fibroblast proliferation may be correlated with such variability. The purpose of this paper was to evaluate the association between the risk of developing radiation-induced late xerostomia and four genetic polymorphisms: TGFβ1 C-509T, TGFβ1 T869C, XRCC3 722C>T and ATM 5557G>A in nasopharyngeal carcinoma patients treated with Intensity Modulation Radiated Therapy.

METHODS

The severity of late xerostomia was assessed using a patient self-reported validated xerostomia questionnaire. Polymerase chain reaction-ligation detection reaction methods were performed to determine individual genetic polymorphism. The development of radiation-induced xerostomia associated with genetic polymorphisms was modeled using Cox proportional hazards, accounting for equivalent uniform dose.

RESULTS

A total of 43 (41.7%) patients experienced radiation-induced late xerostomia. Univariate Cox proportional hazard analyses showed a higher risk of late xerostomia for patients with XRCC3 722 TT/CT alleles. In multivariate analysis adjusted for clinical and dosimetric factors, XRCC3 722C>T polymorphisms remained a significant factor for higher risk of late xerostomia.

CONCLUSIONS

To our knowledge, this is the first study that demonstrated an association between genetic polymorphisms and the risk of radiation-induced late xerostomia in nasopharyngeal carcinoma patients treated with Intensity Modulation Radiated Therapy. Our findings suggest that the polymorphisms in XRCC3 are significantly associated with the risk of developing radiation-induced late xerostomia.

Association of functional FEN1 genetic variants and haplotypes and breast cancer risk

AIM

As a tumor suppressor, FEN1 plays an essential role in preventing tumorigenesis. Two functional germline variants (-69G>A and 4150G>T) in the FEN1 gene have been associated with DNA damage levels in coke-oven workers and multiple cancer risk in general populations. However, it is still unknown how these genetic variants are involved in breast cancer susceptibility.

METHODS

We investigated the association between these polymorphisms and breast cancer risk in two independent case-control sets consisted of a total of 1100 breast cancer cases and 1400 controls. The influence of these variations on FEN1 expression was also examined using breast normal tissues.

RESULTS

It was found that the FEN1-69GG genotypes were significantly correlated to increased risk for developing breast cancer compared with the -69AA genotype in both sets [Jinan set: odds ratios (OR)=1.41, 95% confidence interval (CI)=1.20-1.65, P=1.9×10(-5); Huaian set: OR=1.51, 95% CI=1.22-1.86, P=1.7×10(-4)]. Similar results were observed for 4150G>T polymorphism. The genotype-phenotype correlation analyses demonstrated that the -69G or 4150G allele carriers had more than 2-fold decreased FEN1 expression in breast tissues compared with -69A or 4150T carriers, suggesting that lower FEN1 expression may lead to higher risk for malignant transformation of breast cells.

CONCLUSION

Our findings highlight FEN1 as an important gene in human breast carcinogenesis and genetic variants in FEN1 confer susceptibility to breast cancer.

rs189037, a functional variant in ATM gene promoter, is associated with idiopathic nonobstructive azoospermia

OBJECTIVE

To investigate the relationship between a functional variant rs189037(G>A) in ATM promoter and idiopathic nonobstructive azoospermia (INOA) in a Chinese population.

DESIGN

Case-control study.

SETTING

Medical academy and hospital.

PATIENT(S)

Two hundred twenty-nine INOA patients and 236 fertile male controls.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Genotyping was performed by polymerase chain reaction-based restriction fragment length polymorphism and subsequently confirmed by DNA sequencing. Odds ratio (ORs) and 95% confidence intervals (95% CIs) were calculated for the risk genotype and allele. Bioinformatic analysis was also performed to predict the biological function of rs189037(G>A).

RESULT(S)

The AA genotype and A allele at rs189037(G>A) locus were both associated with an increased risk of INOA, with OR 1.90 (95% CI 1.214-3.007) for AA and 1.41 (95% CI 1.112-1.775) for A allele. The heterozygous GA and GA+AA had no relationship with INOA risk, with OR 1.06 (95% CI 0.761-1.472) and 1.28 (95% CI 0.954-1.708), respectively. Meanwhile, stratification by genotype showed that INOA patients with AA had higher FSH level, lower total T level, and smaller testicular size than those patients with GG. Furthermore, bioinformatic analysis predicted that the rs189037(G>A) variant was located in a well-conserved region in ATM promoter and that the transition of allele G to allele A might lead to differential allelic expression of ATM gene via modifying of the DNA-binding ability of transcription factor E2F1.

CONCLUSION(S)

The genetic variant rs189037(G>A) in ATM gene promoter contributes to an increased risk of INOA in a Chinese population, possibly through affecting the DNA-binding ability of E2F1 and subsequent ATM expression.