Polymorphisms in ERCC1 and susceptibility to childhood acute lymphoblastic leukemia in a Chinese population

Expression and Genetic Polymorphisms of ERCC1 in Chinese Han Patients with Oral Squamous Cell Carcinoma

The aim of this study was to investigate the expression of the excision repair cross-complementation group 1 (ERCC1) in oral squamous cell carcinoma (OSCC) and the possible association of ERCC1 polymorphisms with susceptibility and response to chemotherapy of OSCC in a Chinese Han population. The expression of ERCC1 was determined by real-time PCR in eight patients. Four single-nucleotide polymorphisms (SNPs) rs11615, rs3212948, rs3212961, and rs735482 of ERCC1 were genotyped in 113 OSCC patients and 184 healthy controls using a PCR restriction matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) assay. We found that a higher gene expression of ERCC1 was observed in tumor tissue as compared to pericarcinomatous tissue in OSCC patients. All genotypic and allelic frequencies of the tested ERCC1 polymorphisms were in Hardy-Weinberg equilibrium. The genotypic and allelic frequencies of rs11615, rs3212948, rs3212961, and rs735482 of ERCC1 were not different between OSCC patients and controls. No correlation was observed between ERCC1 polymorphisms and the response to chemotherapy. Our results show that ERCC1 is increased in the tumor tissue of OSCC patients. The investigated ERCC1 gene polymorphisms (rs11615, rs3212948, rs3212961, and rs735482) are not associated with the susceptibility and response to chemotherapy of OSCC in our investigated Chinese Han population.

DNA repair pathways as guardians of the genome: Therapeutic potential and possible prognostic role in hematologic neoplasms

DNA repair pathways, which are also identified as guardians of the genome, protect cells from frequent damage that can lead to DNA breaks. The most deleterious types of damage are double-strand breaks (DSBs), which are repaired by homologous recombination (HR) and non-homologous end joining (NHEJ). Single strand breaks (SSBs) can be corrected through base excision repair (BER), nucleotide excision repair (NER), and mismatch repair (MMR). Failure to restore DNA lesions or inappropriately repaired DNA damage culminates in genomic instability and changes in the regulation of cellular functions. Intriguingly, particular mutations and translocations are accompanied by special types of leukemia. Besides, expression patterns of certain repair genes are altered in different hematologic malignancies. Moreover, analysis of mutations in key mediators of DNA damage repair (DDR) pathways, as well as investigation of their expression and function, may provide us with emerging biomarkers of response/resistance to treatment. Therefore, defective DDR pathways can offer a rational starting point for developing DNA repair-targeted drugs. In this review, we address genetic alterations and gene/protein expression changes, as well as provide an overview of DNA repair pathways.

Sex ratio among childhood cancers by single year of age

BACKGROUND

The male excess in childhood cancer incidence is well-established; however, the underlying biologic mechanisms remain unknown. Examining the association between male sex and childhood cancer by single year of age and tumor type may highlight important periods of risk such as variation in growth and hormonal changes, which will inform etiologic hypotheses.

METHODS

Using data from the Surveillance, Epidemiology, and End Results (SEER) 18 registries (2000-2015), incidence rate ratios (IRR) and 95% confidence intervals (95% CI) were estimated as the measure of association between male sex and childhood cancer by single year of age (0-19).

RESULTS

The IRR for male cancer overall was 1.19 (95% CI, 1.18-1.20) and was similar in magnitude at nearly every year of age. Burkitt lymphoma was strongly associated with male sex (IRRs ≥2 at each year of age). Increased incidence was observed among males for acute lymphoblastic leukemia, Hodgkin and non-Hodgkin lymphomas for nearly all years of age. Medulloblastoma was the only central nervous system tumor with a significant male predominance at nearly every age. Male sex displayed a consistent inverse association with nephroblastoma and thyroid carcinoma over the ages studied.

CONCLUSIONS

Male sex was positively associated with most cancers. The higher incidence rates observed in males remained consistent over the childhood and adolescent periods, suggesting that childhood and adolescent hormonal fluctuations may not be the primary driving factor for the sex disparities in childhood cancer. The observed incidence disparities may be due to sex differences in exposures, genetics, or immune responses.

XPD c.934G>A polymorphism of nucleotide excision repair pathway in outcome of head and neck squamous cell carcinoma patients treated with cisplatin chemoradiation

This study aimed to investigate the associations of XPC c.2815A>C, XPD c.934G>A and c.2251A>C, XPF c.2505T>C and ERCC1 c.354C>T single nucleotide polymorphisms (SNPs) of nucleotide excision repair pathway in outcome of head and neck squamous cell carcinoma (HNSCC) patients treated with cisplatin (CDDP) chemoradiation. Patients with XPC c.2815AC or CC and XPD c.934GA or AA genotypes had 0.20 and 0.38 less chances of presenting moderate/severe ototoxicity and nausea, respectively. Patients with XPD c.934AA and c.2251AC or CC genotypes had 8.64, 12.29 and 3.55 more chances of achieving complete response (CR), consistent ototoxicity and nephrotoxicity, respectively. AA haplotype of XPD and ACT haplotype of XPD and ERCC1 SNPs were associated with 9.30 and 3.41 more chances of achieving CR and consistent nephrotoxicity, respectively. At 24 months of follow-up, patients with XPD c.934AA genotype presented lower progression-free survival and overall survival in Kaplan-Meier estimates, and differences between groups remained the same in univariate Cox analysis. Patients with XPD c.934AA genotype had 2.13 and 2.04 more risks of presenting tumor progression and death than others in multivariate Cox analysis. Our data present preliminary evidence that XPC c.2815A>C, XPD c.934G>A and c.2251A>C, and ERCC1 c.354C>T SNPs alter outcome of HNSCC patients treated with CDDP chemoradiation.

A childhood acute lymphoblastic leukemia genome-wide association study identifies novel sex-specific risk variants

Childhood acute lymphoblastic leukemia (ALL) occurs more frequently in males. Reasons behind sex differences in childhood ALL risk are unknown. In the present genome-wide association study (GWAS), we explored the genetic basis of sex differences by comparing genotype frequencies between male and female cases in a case-only study to assess effect-modification by sex.The case-only design included 236 incident cases of childhood ALL consecutively recruited at the Texas Children's Cancer Center in Houston, Texas from 2007 to 2012. All cases were non-Hispanic whites, aged 1 to 10 years, and diagnosed with confirmed B-cell precursor ALL. Genotyping was performed using the Illumina HumanCoreExome BeadChip on the Illumina Infinium platform. Besides the top 100 statistically most significant results, results were also analyzed by the top 100 highest effect size with a nominal statistical significance (P <0.05).The statistically most significant sex-specific association (P = 4 × 10) was with the single nucleotide polymorphism (SNP) rs4813720 (RASSF2), an expression quantitative trait locus (eQTL) for RASSF2 in peripheral blood. rs4813720 is also a strong methylation QTL (meQTL) for a CpG site (cg22485289) within RASSF2 in pregnancy, at birth, childhood, and adolescence. cg22485289 is one of the hypomethylated CpG sites in ALL compared with pre-B cells. Two missense SNPs, rs12722042 and 12722039, in the HLA-DQA1 gene yielded the highest effect sizes (odds ratio [OR] ∼ 14; P <0.01) for sex-specific results. The HLA-DQA1 SNPs belong to DQA1*01 and confirmed the previously reported male-specific association with DQA1*01. This finding supports the proposed infection-related etiology in childhood ALL risk for males. Further analyses revealed that most SNPs (either direct effect or through linkage disequilibrium) were within active enhancers or active promoter regions and had regulatory effects on gene expression levels.Cumulative data suggested that RASSF2 rs4813720, which correlates with increased RASSF2 expression, may counteract the suppressor effect of estrogen-regulated miR-17-92 on RASSF2 resulting in protection in males. Given the amount of sex hormone-related mechanisms suggested by our findings, future studies should examine prenatal or early postnatal programming by sex hormones when hormone levels show a large variation.

Genetic susceptibility in childhood acute leukaemias: a systematic review

Acute leukaemias (AL) correspond to 25-35% of all cancer cases in children. The aetiology is still sheltered, although several factors are implicated in causality of AL subtypes. Childhood acute leukaemias are associated with genetic syndromes (5%) and ionising radiation as risk factors. Somatic genomic alterations occur during fetal life and are initiating events to childhood leukaemia. Genetic susceptibility has been explored as a risk factor, since environmental exposure of the child to xenobiotics, direct or indirectly, can contribute to the accumulation of somatic mutations. Hence, a systematic review was conducted in order to understand the association between gene polymorphisms and childhood leukaemia risk. The search was performed in the electronic databases PubMed, Lilacs, and Scielo, selecting articles published between 1995 and 2013. This review included 90 case-control publications, which were classified into four groups: xenobiotic system (n = 50), DNA repair (n = 16), regulatory genes (n = 15), and genome wide association studies (GWAS) (n = 9). We observed that the most frequently investigated genes were: NQO1, GSTM1, GSTT1, GSTP1, CYP1A1, NAT2, CYP2D6, CYP2E1, MDR1 (ABCB1), XRCC1, ARID5B, and IKZF1. The collected evidence suggests that genetic polymorphisms in CYP2E1, GSTM1, NQO1, NAT2, MDR1, and XRCC1 are capable of modulating leukaemia risk, mainly when associated with environmental exposures, such as domestic pesticides and insecticides, smoking, trihalomethanes, alcohol consumption, and x-rays. More recently, genome wide association studies identified significant associations between genetic polymorphisms in ARID5B e IKZF1 and acute lymphoblastic leukaemia, but only a few studies have replicated these results until now. In conclusion, genetic susceptibility contributes to the risk of childhood leukaemia through the effects of gene-gene and gene-environment interactions.

Polymorphisms of ERCC1 genotype associated with response to imatinib therapy in chronic phase chronic myeloid leukemia

DNA repair machinery may contribute to the mechanism of the action in imatinib. We examined the association between the single nucleotide polymorphism (SNP) markers involved in the DNA repair enzyme pathway (ERCC1/2/4/5, XRCC1/2/4/5) and the clinical outcomes following an imatinib therapy in chronic phase chronic myeloid leukemia (CML) patients. A total of 169 Korean patients were included. Of the 19 SNPs from these patients, those with the TT genotype of ERCC1 (rs11615) showed a higher probability of achieving major cytogenetic response [P = 0.002, HR 5.14 (95 % CI 1.83-14.43)], complete cytogenetic response [P = 0.012, HR 3.47 (95 % CI 1.31-9.17)], and major molecular response [P = 0.001, HR 5.71 (95 % CI 2.13-15.30)] than those with CC or CT genotypes. This suggests that SNP markers on ERCC1 may predict the response to imatinib therapy, which proposes the potential involvement of the DNA repair machinery in the mechanism of imatinib action in chronic phase CML.

Nucleotide excision repair gene ERCC1 polymorphisms contribute to cancer susceptibility: a meta-analysis

Individual studies of the associations between excision repair cross-complimentary group 1 (ERCC1) polymorphisms and cancer susceptibility have shown inconclusive results. To derive a more precise estimation of the relationship between three well-characterised polymorphisms on ERCC1 and the risk of cancer, we performed a meta-analysis based on 48 publications. We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of the associations. We found that ERCC1 17677A (rs3212961) variant genotypes were associated with significantly increased overall risk of cancer without substantial heterogeneity (AA versus CC, OR = 1.36, 95% CIs: 1.10-1.68; AC versus CC: OR = 1.11, 95% CIs: 0.99-1.26; dominant comparison: AA/AC versus CC: OR = 1.15, 95% CIs: 1.02-1.29; recessive comparison: AA versus AC/CC: OR = 1.25, 95% CIs: 1.05-1.49). The ERCC1 19007 C (rs11615) allele had null effects on overall risk of cancer; but in the stratified analyses, we observed an elevated association in Asian populations with homozygote variants and hospital-based controls. In addition, during further stratified analyses of cancer groups, homozygote variants were found that are associated with lung cancer and smoking-related cancers. Also, the observed ERCC1 19007 C heterozygote variant contributes to the development of skin cancer. However, the ERCC1 8092C > A (rs3212986) polymorphism did not appear to have an effect on cancer risk. Additionally, no evidence of publication bias was observed in these polymorphisms. Our meta-analysis supports the conclusion that the ERCC1 17677A > C and ERCC1 19007T > C polymorphisms, but not the ERCC1 8092C > A polymorphism, are low-penetrance risk factors for cancer development.

DNA repair gene excision repair cross complementing-group 1 (ERCC1) in head and neck squamous cell carcinoma: analysis of methylation and polymorphism (G19007A), protein expression and association with epidemiological and clinicopathological factors

AIMS

To evaluate the associations of excision repair cross complementing-group 1 (ERCC1) (DNA repair protein) (G19007A) polymorphism, methylation and immunohistochemical expression with epidemiological and clinicopathological factors and with overall survival in head and neck squamous cell carcinoma (HNSCC) patients.

METHODS AND RESULTS

The study group comprised 84 patients with HNSCC who underwent surgery and adjuvant radiotherapy without chemotherapy. Bivariate and multivariate analyses were used. The allele A genotype variant was observed in 79.8% of the samples, GG in 20.2%, GA in 28.6% and AA in 51.2%. Individuals aged more than 45 years had a higher prevalence of the allelic A variant and a high (83.3%) immunohistochemical expression of ERCC1 protein [odds ratio (OR) = 4.86, 95% confidence interval (CI): 1.2-19.7, P = 0.027], which was also high in patients with advanced stage (OR=5.04, 95% CI: 1.07-23.7, P = 0.041). Methylated status was found in 51.2% of the samples, and was higher in patients who did not present distant metastasis (OR = 6.67, 95% CI: 1.40-33.33, P = 0.019) and in patients with advanced stage (OR = 5.04, 95% CI: 1.07-23.7, P = 0.041). At 2 and 5 years, overall survival was 55% and 36%, respectively (median = 30 months).

CONCLUSION

Our findings may reflect a high rate of DNA repair due to frequent tissue injury during the lifetime of these individuals, and also more advanced disease presentation in this population with worse prognosis.

Haplotypes of DNA repair and cell cycle control genes, X-ray exposure, and risk of childhood acute lymphoblastic leukemia

BACKGROUND

Acute leukemias of childhood are a heterogeneous group of malignancies characterized by cytogenetic abnormalities, such as translocations and changes in ploidy. These abnormalities may be influenced by altered DNA repair and cell cycle control processes.

METHODS

We examined the association between childhood acute lymphoblastic leukemia (ALL) and 32 genes in DNA repair and cell cycle pathways using a haplotype-based approach, among 377 childhood ALL cases and 448 controls enrolled during 1995-2002.

RESULTS

We found that haplotypes in APEX1, BRCA2, ERCC2, and RAD51 were significantly associated with total ALL, while haplotypes in NBN and XRCC4, and CDKN2A were associated with structural and numerical change subtypes, respectively. In addition, we observed statistically significant interaction between exposure to 3 or more diagnostic X-rays and haplotypes of XRCC4 on risk of structural abnormality-positive childhood ALL.

CONCLUSIONS

These results support a role of altered DNA repair and cell cycle processes in the risk of childhood ALL, and show that this genetic susceptibility can differ by cytogenetic subtype and may be modified by exposure to ionizing radiation. To our knowledge, our study is the first to broadly examine the DNA repair and cell cycle pathways using a haplotype approach in conjunction with X-ray exposures in childhood ALL risk. If confirmed, future studies are needed to identify specific functional SNPs in the regions of interest identified in this analysis.

Current status of excision repair cross complementing-group 1 (ERCC1) in cancer

Cisplatin, carboplatin and oxaliplatin are some of the most widely used anti-cancer agents in solid tumours. The cytotoxicity of platinating agents is directly related to their ability to cause DNA intra-strand crosslinks that trigger a series of intracellular events that ultimately result in cell death. DNA intra-strand crosslinks are processed and repaired by the nucleotide excision repair pathway. It is now clear that nucleotide excision repair (NER) capacity may have a major impact on the emergence of resistance, normal tissue tolerance and patient outcomes. ERCC1 is a key player in NER. In this review, we provide an overview of mammalian NER and then focus on biochemical, structural and pre-clinical aspects of ERCC1. We then present current clinical evidence implicating ERCC1 as a predictive and prognostic marker in cancer. Early evidence also suggests that ERCC1 or the pathways involved in the regulation of ERCC1 expression may be attractive anti-cancer targets. Such agents are expected to potentiate the cytotoxicity of platinating agents and could have a major impact on cancer therapy.