Pharmacogenomic strategies for developing customized chemotherapy in non-small cell lung cancer

MYEOV with High Frequencies of Mutations in Head and Neck Cancers Facilitates Cancer Cell Malignant Behaviors

Cancer driver genes (CDGs) and the driver mutations disrupt the homeostasis of numerous critical cell activities, thereby playing a critical role in tumor initiation and progression. In this study, integrative bioinformatics analyses were performed based on a series of online databases, aiming to identify driver genes with high frequencies of mutations in head and neck cancers. Higher myeloma overexpressed (MYEOV) genetic variation frequency and expression level were connected to a poorer prognosis in head and neck cancer patients. MYEOV was dramatically upregulated within head and neck tumor samples and cells. Consistently, MYEOV overexpression remarkably enhanced the aggressiveness of head and neck cancer cells by promoting colony formation, cell invasion, and cell migration. Conversely, MYEOV knockdown attenuated cancer cell aggressiveness and inhibited tumor growth and metastasis in the oral orthotopic tumor model. In conclusion, MYEOV is overexpressed in head and neck cancer, with greater mutation frequencies correlating to a poorer prognosis in head and neck cancer patients. MYEOV serves as an oncogene in head and neck cancer through the promotion of tumor cell colony formation, invasion, and migration, as well as promoting tumor growth and metastasis in the oral orthotopic tumor model.

KIAA1549 promotes the development and chemoresistance of colorectal cancer by upregulating ERCC2

Colorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide. Chemotherapy is the mainstay of treatment for patients with CRC in II-IV stages. Resistance to chemotherapy occurs commonly, which results in treatment failure. Therefore, the identification of novel functional biomarkers is essential for recognizing high-risk patients, predicting recurrence, and developing new therapeutic strategies. Herein, we assessed the roles of KIAA1549 in promoting tumor development and chemoresistance in colorectal cancer. As a result, we found that KIAA1549 expression is up-regulation in CRC. Public databases revealed a progressive up-regulation of KIAA1549 expression from adenomas to carcinomas. Functional characterization uncovered that KIAA1549 promotes tumor malignant phenotypes and boosts the chemoresistance of CRC cells in an ERCC2-dependent manner. Inhibition of KIAA1549 and ERCC2 effectively enhanced the sensitivity to chemotherapeutic drugs oxaliplatin and 5-fluorouracil. Our findings suggest that endogenous KIAA1549 might function as a tumor development-promoting role and trigger chemoresistance in colorectal cancer partly by upregulating DNA repair protein ERCC2. Hence, KIAA1549 could be an effective therapeutic target for CRC and inhibition of KIAA1549 combined with chemotherapy might be a potential therapeutic strategy in the future.

Genetic and epigenetic alterations in DNA repair genes and treatment outcome of chemoradiotherapy in cervical cancer

Cervical cancer (CaCx) is the deadliest malignancy among women which is caused by human papillomavirus (HPV) and anthro-demographical/clinicopathological factors. HPV oncoproteins E6 and E7 target p53 and RB (retinoblastoma) protein degradation, Ataxia telangiectasia mutated (ATM), ATM-RAD3-related (ATR) inactivation and subsequent impairment of non-homologous end joining (NHEJ), homologous recombination, and base excision repair pathways. There is also an accumulation of genetic and epigenetic alterations in Tumor Growth Suppressors (TGS), oncogenes, and DNA repair genes leading to increased genome instability and CaCx development. These alterations might be responsible for differential clinical response to Cisplatin-based chemoradiotherapy (CRT) in patients. This review explores HPV-mediated DNA damage as a risk factor in CaCx development, the mechanistic role of genetic and epigenetic alterations in DNA repair genes and their association with CRT and outcome, It also explores new possibilities for the development of genetic and epigenetic-based biomarkers for diagnostic, prognostic, and molecular therapeutic interventions.

X-ray cross-complementing family: the bridge linking DNA damage repair and cancer

Genomic instability is a common hallmark of human tumours. As a carrier of genetic information, DNA is constantly threatened by various damaging factors that, if not repaired in time, can affect the transmission of genetic information and lead to cellular carcinogenesis. In response to these threats, cells have evolved a range of DNA damage response mechanisms, including DNA damage repair, to maintain genomic stability. The X-ray repair cross-complementary gene family (XRCC) comprises an important class of DNA damage repair genes that encode proteins that play important roles in DNA single-strand breakage and DNA base damage repair. The dysfunction of the XRCC gene family is associated with the development of various tumours. In the context of tumours, mutations in XRCC and its aberrant expression, result in abnormal DNA damage repair, thus contributing to the malignant progression of tumour cells. In this review, we summarise the significant roles played by XRCC in diverse tumour types. In addition, we discuss the correlation between the XRCC family members and tumour therapeutic sensitivity.

The XRCC1 and TP53 gene polymorphisms are associated with advanced-stage disease and early distant metastasis at diagnosis in non-small cell lung cancer

Background

Studies on single nucleotide polymorphisms (SNPs) in non-small cell lung cancer (NSCLC) suggest that DNA repair capacity may have prognostic implications for disease recurrence and survival. However, there is no study investigating the relationship between SNPs and the risk of metastasis at the time of initial diagnosis in patients with NSCLC.

Objective

This study aimed to investigate the potential predictive value of SNPs in detecting the risk of metastasis at the time of initial diagnosis and poor prognosis in patients with NSCLC.

Material and Methods

In this prospective cohort study, we evaluated 275 patients with NSCLC. Analysis of SNPs from peripheral blood cells was performed by a polymerase chain reaction. Excision repair cross-complementing group 1 (ERCC1)- Asn118Asn, excision repair cross-complementing group 2 (ERCC2)-Lys751Gln, X-ray repair cross-complementing group 1 (XRCC1)-Arg399Gln, and tumor protein 53 (TP53)-Arg72Pro polymorphisms were evaluated in conjunction with the development of metastasis.

Results

The ERCC1 normal genotype, ERCC2 heterozygote genotype, XRCC1 normal genotype, and TP53 normal genotype were associated with a higher stage and more advanced-stage disease at the time of initial diagnosis (P = 0.027, 0.005, <0.001, and 0.006, respectively). Also, XRCC1 normal genotype and TP53 normal genotype were associated with the risk of metastasis at the time of initial diagnosis (P = <0.001 and 0.002, respectively). Moreover, the XRCC1 normal genotype was associated with the risk of brain metastasis at the time of initial diagnosis (P = 0.031).

Conclusions

We showed that SNPs are related to a higher stage and more advanced-stage disease at the time of initial diagnosis in patients with NSCLC, and XRCC1 and TP53 gene polymorphisms are associated with the risk of metastasis. These results may contribute to the identification of high-risk groups and may help to earlier diagnosis and treatment in patients with NSCLC.

Understanding Role of DNA Repair and Cytochrome p-450 Gene Polymorphisms in Cervical Cancer Patient Treated With Concomitant Chemoradiation

Background: Evidences suggest that single nucleotide polymorphisms (SNPs) can be considered as potential biomarkers for disease progression and therapeutic response in cervical cancer. The present study investigated the association of CYP1A1 T>C (rs4646903), CYP1A1 A>G (rs1048943), CYP2E1 T>A (rs6413432), RAD51 G>C (rs1801320), XRCC1 G>A (rs25487), XRCC2 G>A (rs3218536) and XRCC3 C>T (rs861539) polymorphisms with treatment outcome of cisplatin based chemoradiation (CRT).

Methods: Total 227 cervical cancer cases, treated with the same chemoradiotherapy regimen were selected for the study. Genotyping analysis was performed by PCR-restriction fragment length polymorphisms (PCR-RFLP). Treatment response was evaluated by Response Evaluation Criteria in Solid Tumors (RECIST). Association of all clinical data (responses, recurrence and survival of patients) and single nucleotide polymorphisms (SNPs) was analysed by using SPSS (version 21.0).

Results: Patients with TA/AA genotype of CYP2E1 T>A polymorphism showed significantly poor response while those with GC/CC genotype of RAD51 G>C showed better response (p = 0.008, p = 0.014 respectively). Death was significantly higher in patients with GG genotypes of RAD51 G>C and XRCC1 G>A (p = 0.006, p = 0.002 respectively). Women with GC+CC genotype of RAD51 G>C and AG+GG of XRCC1 showed better survival and also reduced risk of death (HR = 0.489, p = 0.008; HR = 0.484, p = 0.003 respectively).

Conclusion: Results suggested that CYP2E1 T>A (rs6413432), RAD51 G>C (rs1801320), and XRCC1 G>A (rs25487) polymorphisms may be used as predictive markers for clinical outcomes in cervical cancer patients undergoing cisplatin based concomitant chemoradiotherapy.

Pharmacogenetic Association between XRCC1 Polymorphisms and Response to Platinum-Based Chemotherapy in Asian Patients with NSCLC: A Meta-Analysis

Background

Platinum-based chemotherapy plays an antitumor role by damaging DNA. X-ray repair crosscomplementing protein 1 (XRCC1) participates in DNA repair and thus affects the sensitivity to platinum drugs. Two polymorphisms of XRCC1, rs25487 (Arg399Gln) and rs1799782 (Arg194Trp), have been widely studied for the association with clinical outcomes of platinum-based chemotherapy in Asian patients with non-small-cell lung cancer (NSCLC), but the results remain inconclusive. Thus, we performed the present meta-analysis.

Methods

Literature search was performed in PubMed, Web of Science, and EMBASE up to June 2019. Odds ratios (ORs) for objective response ratio (ORR), Cox proportional hazard ratios (HRs) of overall survival (OS) and progression-free survival (PFS), and the corresponding 95% confidence intervals (95% CIs) were calculated to assess the association strengths between XRCC1 polymorphisms and clinical outcomes. Comparisons were performed in homozygous, heterozygous, dominant, and recessive models.

Results

Finally, a total of 23 studies involving 5567 patients were included in the meta-analysis. Compared to ArgArg of rs25487, GlnGln (OR = 1.71, 95% CI: 1.16-2.52, p = .007, I² = 56.8%) and GlnArg (OR = 1.23, 95% CI: 1.07-1.40, p = .003, I² = 29.0%) were associated with higher ORR. Meanwhile, GlnGln indicated a favorable OS (HR = 0.60, 95% CI: 0.40-0.88) and PFS (HR = 0.64, 95% CI: 0.46-0.90). We also found positive associations between rs1799782 and ORR in all comparison models with low between-study heterogeneity. The association strength increased with the number of variant alleles (TrpTrp vs. ArgArg: OR = 1.73, 95% CI:1.31-2.27; TrpArg vs. ArgArg: OR = 1.28, 95% CI: 1.06-1.55), suggesting a gene dosage effect. In addition, TrpTrp predicted a longer OS.

Conclusion

Our results showed that rs25487 and rs1799782 of XRCC1 are potential markers to predict clinical outcomes of platinum-based chemotherapy in Asian patients with NSCLC.

DNA helicases and their roles in cancer

DNA helicases, known for their fundamentally important roles in genomic stability, are high profile players in cancer. Not only are there monogenic helicase disorders with a strong disposition to cancer, it is well appreciated that helicase variants are associated with specific cancers (e.g., breast cancer). Flipping the coin, DNA helicases are frequently overexpressed in cancerous tissues and reduction in helicase gene expression results in reduced proliferation and growth capacity, as well as DNA damage induction and apoptosis of cancer cells. The seminal roles of helicases in the DNA damage and replication stress responses, as well as DNA repair pathways, validate their vital importance in cancer biology and suggest their potential values as targets in anti-cancer therapy. In recent years, many laboratories have characterized the specialized roles of helicase to resolve transcription-replication conflicts, maintain telomeres, mediate cell cycle checkpoints, remodel stalled replication forks, and regulate transcription. In vivo models, particularly mice, have been used to interrogate helicase function and serve as a bridge for preclinical studies that may lead to novel therapeutic approaches. In this review, we will summarize our current knowledge of DNA helicases and their roles in cancer, emphasizing the latest developments.

Association of XPD Lys751Gln gene polymorphism with susceptibility and clinical outcome of colorectal cancer in Pakistani population: a case-control pharmacogenetic study

BACKGROUND

XPD Lys751Gln polymorphism may modulate inter-individual variation in repair capacity of DNA, which may enhance a person's susceptibility to develop colorectal cancer (CRC). The analysis of XPD Lys751Gln polymorphism may provide important information for identifying high-risk individuals and for selecting the most appropriate treatment for poor prognostic CRC patients.

OBJECTIVE

The overall objective was to find out the association of XPD Lys751Gln gene polymorphism with the risk of having a colorectal cancer and the ultimate clinical outcomes. In this study a total of 300 subjects (CRC and Controls), were genotyped for XPD Lys751Gln.

METHODS

Using PCR-RFLP methods, the association of XPD Lys751Gln gene polymorphism with the risk of having a colorectal cancer was studied. In addition to overall risk assessment, genotyping results were also investigated with respect to the lifestyle risk factors, patients treated with oxaliplatin-based chemotherapy and clinicopathological characteristics.

RESULTS

The overall correlation between the XPD Lys751Gln genetic variation and the CRC risk was observed to be significant with both the homozygous variant genotype Gln/Gln as well as heterozygous genotype Lys/Gln being associated with the increased risk of CRC. Additional stratified analyses revealed that XPD Lys751Gln variants remarkably increased risk of CRC in males and younger individuals (≤ 50 years), Naswar users (8.09-fold) and high intake of red meat.

CONCLUSIONS

Our findings suggest that the relationship between the XPD Lys751Gln variants and lifestyle factors modulates the risk for CRC in Pakistani population.

XRCC1 polymorphism and overall survival in ovarian cancer patients treated with platinum-based chemotherapy: A systematic review and MOOSE-compliant meta-analysis

OBJECTIVES

Although platinum-based chemotherapy is widely used for advanced ovarian cancer (OC), genetic polymorphisms can influence the chemotherapeutic response. This study investigated the association between XRCC1 polymorphisms Arg194Trp, Arg280His, and Arg399Gln, and overall survival (OS) in OC patients who received platinum-based chemotherapy.

METHODS

We systematically searched PubMed, Embase, the Cochrane library, Chinese National Knowledge Infrastructure, Wanfang, and Weipu databases for relevant studies from inception to October, 2017. OS was calculated using a random-effects model. Sensitivity, subgroup, and publication bias analyses were also performed.

RESULTS

Five studies involving 1159 OC patients were included. When compared with 194ArgArg, 194TrpTrp (hazard ratio [HR] 1.09, 95% confidence interval [CI] 0.71-1.69, P = .69) and 194TrpArg (HR 1.00, 95% CI 0.78-1.28, P = .98) carriers were not associated with OS. Similarly, compared with 280ArgArg carriers, neither 280HisHis (HR 1.39, 95% CI 0.82 to -2.34, P = .22) nor 280HisArg (HR 0.98, 95% CI 0.73 to -1.31, P = .90) affected OS. Furthermore, there were no significant differences in OS between 399GlnGln (HR 1.00, 95% CI 0.46-2.16, P > .99), 399GlnArg (HR 1.05, 95% CI 0.81-1.37, P = .70), and 399ArgArg. Finally, subgroup analysis suggested that 399GlnGln significantly decreased OS when the percentage of III or IV cases was >80.0% (HR 1.79, 95% CI 1.22-2.62, P = .003), while OS was increased when this percentage was <80.0% (HR 0.47, 95% CI 0.28-0.79, P = .004).

CONCLUSIONS

This study indicated that XRCC1 Arg194Trp, Arg280His, and Arg399Gln did not affect OS after platinum-based chemotherapy in OC patients. However, disease status could affect the relationship between Arg399Gln and OS in these patients.

Immunohistochemistry Biomarkers Predict Survival in Stage II/III Gastric Cancer Patients: From a Prospective Clinical Trial

Purpose

Identification of biomarkers to predict recurrence risk is essential to improve adjuvant treatment strategies in stage II/III gastric cancer patients. This study evaluated biomarkers for predicting survival after surgical resection.

Materials and Methods

This post-hoc analysis evaluated patients from the CLASSIC trial who underwent D2 gastrectomywith orwithout adjuvant chemotherapy (capecitabine plus oxaliplatin) at the Yonsei Cancer Center. Tumor expressions of thymidylate synthase (TS), excision repair cross-complementation group 1 (ERCC1), and programmed death-ligand 1 (PD-L1) were evaluated by immunohistochemical (IHC) staining to determine their predictive values.

Results

Among 139 patients, IHC analysis revealed high tumor expression of TS (n=22, 15.8%), ERCC1 (n=23, 16.5%), and PD-L1 (n=42, 30.2%) in the subset of patients. Among all patients, high TS expression tended to predict poor disease-free survival (DFS; hazard ratio [HR], 1.80; p=0.053), whereas PD-L1 positivity was associated with favorable DFS (HR, 0.33; p=0.001) and overall survival (OS; HR, 0.38; p=0.009) in multivariate Cox analysis. In the subgroup analysis, poor DFS was independently predicted by high TS expression (HR, 2.51; p=0.022) in the adjuvant chemotherapy subgroup (n=66). High PD-L1 expression was associated with favorable DFS (HR, 0.25; p=0.011) and OS (HR, 0.22; p=0.015) only in the surgery-alone subgroup (n=73). The prognostic impact of high ERCC1 expression was not significant in the multivariate Cox analysis.

Conclusion

This study shows that high TS expression is a predictive factor for worse outcomes on capecitabine plus oxaliplatin adjuvant chemotherapy, whereas PD-L1 expression is a favorable prognostic factor in locally advanced gastric cancer patients.

Systemic Therapy for Advanced Urothelial Carcinoma: Current Standards and Treatment Considerations

Urothelial carcinoma is the sixth most common malignancy in the United States. Although most are diagnosed with non-muscle-invasive malignancy, many patients will develop recurrent disease within 5 years, with 10% to 20% developing advanced muscle-invasive or more distant incurable disease. For such patients, clinical outcomes have remained suboptimal, although recent therapeutic advances have brought new hope to the field. Here, we discuss the main systemic treatment options available for the treatment of patients with advanced disease. This review begins with traditional chemotherapy, which remains a first-line treatment option for many patients. The second section focuses on the evolving landscape of immunotherapy, specifically on approved checkpoint inhibitors and future challenges. Last, we address advances in targeted treatments, including angiogenesis and fibroblast growth factor receptor (FGFR) inhibitors as well as antibody-drug conjugates. As the number of available treatment options continues to expand, ongoing trials to investigate the best sequence and combination strategies to incorporate these drugs into clinical practice will help delineate the future.

SNPs in predicting clinical efficacy and toxicity of chemotherapy: walking through the quicksand

In the "precision medicine" era, chemotherapy still remains the backbone for the treatment of many cancers, but no affordable predictors of response to the chemodrugs are available in clinical practice. Single nucleotide polymorphisms (SNPs) are gene sequence variations occurring in more than 1% of the full population, and account for approximately 80% of inter-individual genomic heterogeneity. A number of studies have investigated the predictive role of SNPs of genes enrolled in both pharmacodynamics and pharmacokinetics of chemotherapeutics, but the clinical implementation of related results has been modest so far. Among the examined germline polymorphic variants, several SNPs of dihydropyrimidine dehydrogenase (DPYD) and uridine diphosphate glucuronosyltransferases (UGT) have shown a robust role as predictors of toxicity following fluoropyrimidine- and/or irinotecan-based treatments respectively, and a few guidelines are mandatory in their detection before therapy initiation. Contrasting results, however, have been reported on the capability of variants of other genes as MTHFR, TYMS, ERCC1, XRCC1, GSTP1, CYP3A4/3A5 and ABCB1, in predicting either therapy efficacy or toxicity in patients undergoing treatment with pyrimidine antimetabolites, platinum derivatives, irinotecan and taxanes. While formal recommendations for routine testing of these SNPs cannot be drawn at this moment, therapeutic decisions may indeed benefit of germline genomic information, when available. Here, we summarize the clinical impact of germline genomic variants on the efficacy and toxicity of major chemodrugs, with the aim to facilitate the therapeutic expectance of clinicians in the odiern quicksand field of complex molecular biology concepts and controversial trial data interpretation.

Tip60: updates

The maintenance of genome integrity is essential for organism survival. Therefore, eukaryotic cells possess many DNA repair mechanisms in response to DNA damage. Acetyltransferase, Tip60, plays a central role in ATM and p53 activation which are involved in DNA repair. Recent works uncovered the roles of Tip60 in ATM and p53 activation and how Tip60 is recruited to double-strand break sites. Moreover, recent works have demonstrated the role of Tip60 in cancer progression. Here, we review the current understanding of how Tip60 activates both ATM and p53 in response to DNA damage and his new roles in tumorigenesis.

A functional polymorphism of SSBP1 gene predicts prognosis and response to chemotherapy in resected gastric cancer patients

Growing evidence has indicated that single-stranded DNA-binding proteins 1 (SSBP1) is involved in tumor initiation and progression. However, effects of single nucleotide polymorphisms (SNPs) in SSBP1 gene on gastric cancer (GC) prognosis are still unknown. In present study, two functional SNPs from SSBP1 were selected and genotyped in a large cohorts of 1030 resected GC patients (326 in the training set, 704 in the validation set) to explore the association of SNPs with patients’ survival. The rs6976500 G allele (CG/GG) genotypes were found significantly associated with both worse overall survival (OS) and recurrence-free survival (RFS) in the training and the independent validation set when compared to C allele genotype, which reaching a more robust statistical significance in the pooled analysis. Furthermore, integration of rs6976500 genotypes and TNM stage significantly improved the prognosis prediction models based on TNM stage alone. In addition, only carriers with at least one G allele of rs6976500 gained significant survival benefit from FOLFOX-based ACT. Mechanistically, SNP rs6976500 G allele genotype could significantly decrease promoter transcriptional activity and markedly reduce expression level of SSBP1 compared with the C allele genotype in GC cells. This was further substantiated by immunohistochemical assay in 70 GC tissue samples. Our study presents the first evidence that SNP rs6976500 G allele genotypes might contribute to GC prognosis by attenuating SSBP1 promoter activity and gene expression, and provides the guidance in refining therapeutic decisions of GC patients. Further exploration on its function is needed to clarify the exact biological mechanism behind.

GSTT1, GSTP1, and GSTM1 genetic variants are associated with survival in previously untreated metastatic breast cancer

Purpose

The polymorphisms in genes including GSTM1, GSTP1 and GSTT1 have been found to predict development and therapeutic efficacy in various malignancies. Breast cancer is one of most common cancers among women. In this study, we evaluated the prognostic value of three functional polymorphisms of GSTs in patients with previously untreated metastatic breast cancer (MBC).

Patients and Methods

The genotype of GSTT1, GSTP1, and GSTM1 in 170 patients with previously untreated MBC from one single center were assessed via PCR-based RFLP methods. The prognostic of polymorphisms on overall survival (OS) was examined using the Kaplan-Meier estimates and Cox proportional hazard ratio (HR) regression analyses.

Results

The null genotypes of GSTT1 and GSTM1 were significantly correlated to poor OS compared with the present genotypes, respectively. After adjusting for clinic-pathologic factors, GSTT1 and GSTM1 genetic variants were still significantly associated with OS (HR, 1.92; 95% CI, 1.26-2.91 and HR, 1.53; 95% CI, 1.05-2.23). GSTT1 and GSTM1 were independent survival predictors and GSTP1 was not associated with overall survival of previous untreated MBC.

Conclusion

This exploratory analysis suggests that in addition to clinic-pathologic factors, the genetic variants in GSTT1 and GSTM1 might be predictive of survival outcome in patients with previously untreated MBC.

Development of diagnostic model of lung cancer based on multiple tumor markers and data mining

Objective

To develop early intelligent discriminative model of lung cancer and evaluate the efficiency of diagnosis value.

Methods

Based on the genetic polymorphism profile of CYP1A1-rs1048943, GSTM1, mEH-rs1051740, XRCC1-rs1799782 and XRCC1-rs25489 and the methylations of p16 and RASSF1A gene, and the length of telomere in the peripheral blood from 200 lung cancer patients and 200 health persons, the discriminative model was established through decision tree and ANN technique.

Results

ACU of the discriminative model based on multiple tumour markers increased by about 10%; The accuracy rate of decision tree model and ANN model for testing set were 93.00% and 89.62% respectively. The ROC analysis showed the decision tree model’s AUC is 0.929 (0.894∼0.964), the ANN model’s AUC is 0.894 (0.853∼0.935). However, the classify accuracy rate and AUC of Fisher discriminatory analysis model are all about 0.7.

Conclusion

The early intelligent discriminative model of lung cancer based on multiple tumor markers and data mining techniques has a higher accuracy rate and might be useful for early diagnosis of lung cancer.

Genetic variants in ERCC1 and XPC predict survival outcome of non-small cell lung cancer patients treated with platinum-based therapy

Nucleotide excision repair (NER) plays a vital role in platinum-induced DNA damage during chemotherapy. We hypothesize that regulatory single nucleotide polymorphisms (rSNPs) of the core NER genes modulate clinical outcome of patients with advanced non-small cell lung cancer (NSCLC) treated with platinum-based chemotherapy (PBS). We investigated associations of 25 rSNPs in eight NER genes with progression free survival (PFS) and overall survival (OS) in 710 NSCLC patients. We found that ERCC1 rs3212924 AG/GG and XPC rs2229090 GC/CC genotypes were associated with patients’ PFS (HR_adj = 1.21, 95% CI = 1.03–1.43, P_adj = 0.021 for ERCC1 and HR_adj = 0.80, 95% CI = 0.68–0.94, P_adj = 0.007 for XPC), compared with the AA and GG genotypes, respectively. The association of XPC rs2229090 was more apparent in adenocarcinoma than in squamous cell carcinoma patients. Additionally, ERCC4 rs1799798 GA/AA genotypes were associated with poorer OS (HR_adj = 1.32, 95% CI = 1.04–1.69, P_adj = 0.026), compared with the GG genotype. The expression quantitative trait loci analysis revealed that ERCC1 rs3212924 and XPC rs2229090 might regulate transcription of their genes, which is consistent with their associations with survival. Larger studies are needed to validate our findings with further functional studies to elucidate the mechanisms underlying these observed associations.

A systematic and genome-wide correlation meta-analysis of PD-L1 expression and targetable NSCLC driver genes

BACKGROUND

Studies have shown that the ligand of programmed cell death protein 1 (B7-H1, CD274 or PD-L1) is related to lung cancer driver genes. Although studies have examined the association between lung cancer driver gene mutations or expression and PD-L1 expression, the present studies have not been mined the correlation systematically and genome-widely.

METHODS

All relevant published PD-L1 articles with driver genes data and the RNA-seq dataset from The Cancer Genome Atlas (TCGA) were analyzed. We performed meta-analysis for data included in the selected literature, and then independently explored the correlation between genes by co-expression analysis of RNA-seq data in the TCGA database.

RESULTS

A sum of 9,934 lung cancer cases were collected from 34 published studies. Higher PD-L1 expression was associated with wild-type epidermal growth factor receptor (EGFR) [odds ratio (OR): 0.68, 95% confidence interval (CI): 0.48-0.96, P=0.03], Kirsten rat sarcoma viral oncogene homolog (KRAS) mutation (OR: 1.27, 95% CI: 1.02-1.58, P=0.03) or non-adenocarcinoma histology (OR: 0.68, 95% CI: 0.47-0.98, P=0.04). In addition, our analysis from TCGA data indicated that, compared with lung adenocarcinoma, the expression of PD-L1 was significantly higher than that of squamous cell carcinoma patients (P=0.023). The expression of targetable driver genes showed no correlations with PD-L1 expression in non-small cell lung cancer (NSCLC).

CONCLUSIONS

Our results suggest the presence of EGFR wild-type, KRAS gene mutations or squamous cell carcinoma were associated with high PD-L1expression, which provides potential benefited population for the administration of PD-1/PD-L1 blockade in human lung cancer.

Association between the XRCC1 polymorphisms and clinical outcomes of advanced NSCLC treated with platinum-based chemotherapy: a meta-analysis based on the PRISMA statement

Background

Base excision repair (BER) pathway is a DNA repair pathway that is important in carcinogenesis and in response to DNA-damaging chemotherapy. XRCC1 is one of important molecular markers for BER. So far, the role of XRCC1 polymorphisms with clinical outcomes of advanced NSCLC treated with platinum-based chemotherapy is inconclusive. To explore the relationship between XRCC1 polymorphisms and platinum-based chemotherapy in advanced NSCLC patients, we performed this meta-analysis.

Methods

Crude odds ratios (ORs), Cox proportional hazard ratios (HRs) with the corresponding 95% confidence intervals (CIs) were adopted to assess the strength of association between XRCC1 polymorphisms and response rate, Overall survival (OS) and progression free survival (PFS) of advanced NSCLC treated with platinum-based chemotherapy. Q test and I² test were used for the assessment of heterogeneity. Subgroup analyses were conducted when heterogeneity exists. Begg’s funnel plots and Egger’s linear regression test were used to estimate publication bias. Sensitivity analysis was performed to evaluate the stability of the result.

Results

A total of 19 studies including 2815 individuals were eligible for the analysis, results showed XRCC1 194Arg allele was negatively associated with the objective response rate relative to 194Trp, and results of homozygous model, dominant model and heterozygous model suggested a gene dosage effect negative correlation between 194Arg allele and objective response rate(ArgArg vs TrpTrp: OR = 0.64(95%CI: 0.44-0.91); ArgArg + TrpArg vs TrpTrp: OR = 0.79(95%CI: 0.57-1.11); TrpArg vs TrpTrp: OR = 1.05(95%CI: 0.73-1.51)). XRCC1 399Gln may indicate favorable overall survival (GlnGln + GlnArg vs ArgArg: HR = 0.65(95%CI: 0.43–0.98)) and favorable PFS (GlnGln vs ArgArg: HR = 0.72(95%CI: 0.48–0.97)) in Asian patients; while in Caucasian patients, XRCC1 399Gln indicated poorer overall survival (GlnGln vs ArgArg: HR = 2.29(95%CI: 1.25–3.33)).

Conclusions

Our results indicated that in NSCLC patients treated with platinum-based regimen, XRCC1 194Arg allele suggest poor objective response rate, the GlnGln genotype of XRCC1 399 suggest poorer overall survival in Caucasian patients, and longer PFS in Asian patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3487-y) contains supplementary material, which is available to authorized users.

Genetic Polymorphisms and Platinum-based Chemotherapy Treatment Outcomes in Patients with Non-Small Cell Lung Cancer: A Genetic Epidemiology Study Based Meta-analysis

Data regarding genetic polymorphisms and platinum-based chemotherapy (PBC) treatment outcomes in patients with NSCLC are published at a growing pace, but the results are inconsistent. This meta-analysis integrated eligible candidate genes to better evaluate the pharmacogenetics of PBC in NSCLC patients. Relevant studies were retrieved from PubMed, Chinese National Knowledge Infrastructure and WANFANG databases. A total of 111 articles comprising 18,196 subjects were included for this study. The associations of genetic polymorphisms with treatment outcomes of PBC including overall response rate (ORR), overall survival (OS) and progression-free survival (PFS) were determined by analyzing the relative risk (RR), hazard ration (HR), corresponding 95% confidence interval (CI). Eleven polymorphisms in 9 genes, including ERCC1 rs11615 (OS), rs3212986 (ORR), XPA rs1800975 (ORR), XPD rs1052555 (OS, PFS), rs13181 (OS, PFS), XPG rs2296147 (OS), XRCC1 rs1799782 (ORR), XRCC3 rs861539 (ORR), GSTP1 rs1695 (ORR), MTHFR rs1801133 (ORR) and MDR1 rs1045642 (ORR), were found significantly associated with PBC treatment outcomes. These variants were mainly involved in DNA repair (EXCC1, XPA, XPD, XPG, XRCC1 and XRCC3), drug influx and efflux (MDR1), metabolism and detoxification (GSTP1) and DNA synthesis (MTHFR), and might be considered as potential prognostic biomarkers for assessing objective response and progression risk in NSCLC patients receiving platinum-based regimens.

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.

Polymorphism in XRCC1 gene modulates survival and clinical outcomes of advanced North Indian lung cancer patients treated with platinum-based doublet chemotherapy

Survival in lung cancer patients is genetically determined. Single nucleotide polymorphisms (SNPs) in DNA repair genes are observed to play a critical role in survival as DNA repair itself can behave as double-edged sword. We aim to explore the association of DNA repair gene XRCC1 in survival and clinical outcomes for North Indian population. Blood sample from patients diagnosed with lung cancer was taken. DNA isolation and genotyping were performed for the SNPs of XRCC1 gene. Further, patients were followed up through telephonic conversation after every 2 months for 3 years. Statistical analysis was carried out using Kaplan-Meier to determine the median survival time (MST) and Cox proportional regression model to determine the hazards ratio. Further, logistic regression was used to calculate to calculate the objective response. The mutant genotype for XRCC1 399 is observed to have a better survival (MST = 9.6). Histological stratification did not reveal any association for any SNP except for SCLC subtype in XRCC1 632 with an increased death rate (HR 3.08, p = 0.02). On stratification according to chemotherapy regimen administered; cisplatin/carboplatin + docetaxel was observed to increase survival for XRCC1 399 mutant genotype (AA) (HR 0.26, p = 0.05). Cisplatin/carboplatin + irinotecan increased survival in both heterozygotes (GA) and combined variants (GA + AA) (HR 0.22, p = 0.014; HR 0.23, p = 0.012). The polymorphic variants within the XRCC1 gene have found to play an important role in overall survival of lung cancer patients undergoing specific chemotherapy regimen.

Correlation of DNA Repair Gene Polymorphisms With Clinical Outcome in Patients With Locally Advanced Non-Small-Cell Lung Cancer Receiving Induction Chemotherapy Followed by Surgery

OBJECTIVE

The aim of this study was to evaluate whether xeroderma pigmentosum group D (XPD) and ribonucleotide reductase subunit M1 (RRM1) polymorphisms influenced clinical outcome in patients with stage IIIA-B non-small-cell lung cancer (NSCLC) treated with neoadjuvant gemcitabine/cisplatin/docetaxel followed by surgery.

MATERIALS AND METHODS

A total of 109 patients with stage IIIA and IIIB NSCLC were prospectively genotyped to examine a potential association between XPD 312 (aspartic acid [Asp]/asparagine [Asn]), XPD 751 (lysine [Lys]/glutamine [Gln]), and RRM1 (-37 C/A) polymorphisms with response and survival.

RESULTS

The median survival was 32.14 months for carriers of XPD 312 Asp/Asp and 12.04 months for those with the variant Asn allele (P = .05). In addition, event-free survival was longer for patients with the XPD 312 Asp/Asp genotype compared with patients with Asp/Asn or Asn/Asn (P = .03). A similar but nonsignificant trend was observed for the XPD 751 genotype. In a multivariate analysis, complete resection and age emerged as prognostic factors for overall survival; in patients with incomplete resection or exploratory thoracotomy, XPD 312 was the most significant prognostic factor (P = .03).

CONCLUSION

The XPD 312 single nucleotide polymorphism is a prognostic factor for survival in patients with locally advanced NSCLC receiving induction chemotherapy followed by surgery. The Asn allele is associated with unfavorable outcome and could be used for better stratification of patients.

ERCC1 and XRCC1 but not XPA single nucleotide polymorphisms correlate with response to chemotherapy in endometrial carcinoma

Our study aimed to investigate the correlation between single nucleotide polymorphisms of ERCC1/XRCC1/XPA genes and postoperative chemotherapy efficacy and prognosis of endometrial carcinoma. Our study included 108 patients with endometrial carcinoma and 100 healthy participants. ERCC1 rs11615/XRCC1 rs25487/XPA rs1800975 gene polymorphisms were detected by polymerase chain reaction-restriction fragment length polymorphism. Then the chemotherapy efficacy and toxic effects of the patients were assessed. The genotype and allele frequency of ERCC1 rs11615/XRCC1 rs25487 in the case group were significantly different from that in the control group (all P<0.05). The patients with AA + GA in ERCC1 rs11615 had an increased risk of endometrial carcinoma than those with GG, and the risk of endometrial carcinoma for patients with AA + GA was also higher in comparison with patients with GG genotype in XRCC1 rs25487 (all P<0.05). GG on both ERCC1 rs11615/XRCC1 rs25487 had a higher effective rate of chemotherapy than GA + AA (all P<0.05). ERCC1 rs11615/XRCC1 rs25487 gene polymorphisms were linked with toxic effects in liver, kidney, and nervous system. ERCC1 rs11615/XRCC1 rs25487, muscular invasion, and tumor stage were independent risk factors for the prognosis of endometrial carcinoma (all P<0.05). However, no significant associations were observed between XPA rs1800975 polymorphism and chemotherapy efficacy and prognosis of endometrial carcinoma (all P>0.05). These results indicated that ERCC1 and XRCC1 but not XPA polymorphisms correlate with response to chemotherapy in endometrial carcinoma.

RAD18 polymorphisms are associated with platinum-based chemotherapy toxicity in Chinese patients with non-small cell lung cancer

AIM

Although targeted therapy is very efficient for lung cancer, traditional platinum-based chemotherapies are still the principal strategy in the absence of positive biomarkers. The aim of the present study is to evaluate the contribution of RAD18 polymorphisms to platinum-chemotherapy response and its potential side effects in Chinese patients with non-small cell lung cancer (NSCLC).

METHODS

A total of 1021 Chinese patients with histological diagnosis of advanced NSCLC were enrolled. Treatment responses were classified into 4 categories (complete response, partial response, stable disease and progressive disease). Gastrointestinal and hematological toxicity incidences were assessed twice a week during the first-line treatment. Ten RAD18 SNPs were genotyped. A logistic regression model was utilized to analyze the associations between RAD18 SNPs and treatment response or toxicity.

RESULTS

Among the 10 SNPs tested, none was significantly correlated with the treatment response in a combined cohort. For gastrointestinal toxicity incidences, rs586014 was significantly associated with an increased risk of grade 3 or 4 gastrointestinal toxicity in non-smokers and in the combined cohort; rs654448 and rs618784 were significantly associated with gastrointestinal toxicity in non-smokers; rs6763823 was significantly associated with gastrointestinal toxicity in smokers. For hematological toxicity incidences, rs586014, rs654448 and rs618784 were significantly associated with hematologic toxicity in non-smokers; rs6763823 and rs9880051 were significantly associated with leukocytopenia in smokers.

CONCLUSION

RAD18 polymorphisms are correlated with the side effects of platinum-chemotherapy in Chinese patients with advanced NSCLC.

Single nucleotide polymorphisms in DNA repair genes and putative cancer risk

Single nucleotide polymorphisms (SNPs) are the most frequent type of genetic alterations between individuals. An SNP located within the coding sequence of a gene may lead to an amino acid substitution and in turn might alter protein function. Such a change in protein sequence could be functionally relevant and therefore might be associated with susceptibility to human diseases, such as cancer. DNA repair mechanisms are known to play an important role in cancer development, as shown in various human cancer syndromes, which arise due to mutations in DNA repair genes. This leads to the question whether subtle genetic changes such as SNPs in DNA repair genes may contribute to cancer susceptibility. In numerous epidemiological studies, efforts have been made to associate specific SNPs in DNA repair genes with altered DNA repair and cancer. The present review describes some of the common and most extensively studied SNPs in DNA repair genes and discusses whether they are functionally relevant and subsequently increase the likelihood that cancer will develop.

Prediction role of seven SNPs of DNA repair genes for survival of gastric cancer patients receiving chemotherapy

We aimed to investigate DNA repair gene expression of response to chemotherapy among gastric patients, and roles in the prognosis of gastric cancer. A total of 209 gastric cancer patients were included in this study between January 2007 and December 2008, all treated with chemotherapy. Polymorphisms were detected by real time PCR with TaqMan probes, and genomic DNA was extracted from peripheral blood samples. The overall response rate was 61.2%. The median progression and overall survivals were 8.5 and 18.7 months, respectively. A significant increased treatment response was found among patients with XPG C/T+T/T or XRCC1 399G/ A+A/A genotypes, with the OR (95% CI) of 2.14 (1.15-4.01) and 1.75 (1.04-3.35) respectively. We found XPG C/T+T/T and XRCC1 399 G/A+A/A were associated with a longer survival among gastric cancer patients when compared with their wide type genotypes, with HRs and 95% CIs of 0.49 (0.27-0.89) and 0.56 (0.29-0.98) respectively. Selecting specific chemotherapy based on pretreatment genotyping may be an innovative strategy for further studies.

Role of BCL2-associated athanogene in resistance to platinum-based chemotherapy in non-small-cell lung cancer

The present study aimed to address the pharmacogenetic role of BAG1 in platinum-based chemotherapy in advanced non-small-cell lung cancer (NSCLC) and in cultured human lung adenocarcinoma A549 cells. A total of 108 NSCLC patients (stages I-IIIA) were treated with a standard chemotherapy regimen of cisplatin plus vinorelbine. Additionally, in vitro cultured A549 cells were treated with cisplatin in the presence or absence of tunicamycin. Cell proliferation was determined by MTT assay and protein levels were assessed via western blot analysis. Patients with BAG1-positive expression were revealed to have a prolonged survival time (progression-free survival, 24.0 months) compared with that of patients without BAG1 expression (21.6 months; χ²=18.018, P<0.05). Treatment of A549 cells with tunicamycin followed by cisplatin resulted in elevated BAG1 levels. In addition, tunicamycin was found to significantly enhance cisplatin-induced growth inhibition and apoptosis in A549 cells. The results indicate that BAG1 is important in cisplatin-induced cell death in lung adenocarcinoma, suggesting that endoplasmic reticulum stress may promote the sensitivity of NSCLC patients to chemotherapy.

Predictive assessment in pharmacogenetics of XRCC1 gene on clinical outcomes of advanced lung cancer patients treated with platinum-based chemotherapy

Published data have shown inconsistent results about the pharmacogenetics of XRCC1 gene on clinical outcomes of advanced lung cancer patients treated with platinum-based chemotherapy. This meta-analysis aimed to summarize published findings and provide more reliable association. A total of 53 eligible studies including 7433 patients were included. Patients bearing the favorable TrpTrp and TrpArg genotypes of Arg194Trp were more likely to better response rates to platinum-based chemotherapy compared to those with the unfavorable ArgArg genotype (TrpTrp+TrpArg vs. ArgArg: odds ratio (OR) = 2.02, 95% CI, 1.66–2.45). The GlnGln and GlnArg genotypes of Arg399Gln were significantly associated with the poorer response rates compared to those with the ArgArg genotype (GlnGln +GlnArg vs. ArgArg: OR = 0.68, 95% CI, 0.54–0.86). The GlnGln genotype might be more closely associated with shorter survival time and higher risks of death for patients (GlnGln vs. ArgArg: hazard ratio (HR) = 1.14, 95% CI, 0.75–1.75). Our cumulative meta-analyses indicated a distinct apparent trend toward a better response rate for Arg194Trp, but a poorer response rate in Arg399Gln. These findings indicate a predictive role of XRCC1 polymorphisms in clinical outcomes. The use of XRCC1 polymorphisms as predictive factor of clinical outcomes in personalized chemotherapy treatment requires further verification from large well-designed pharmacogenetics studies.

Glutathione S-Transferase Gene Polymorphisms and Treatment Outcome in Cervical Cancer Patients under Concomitant Chemoradiation

PURPOSE

Cisplatin based concomitant chemoradiation (CRT) is the standard treatment for locally advanced cervical cancer (CC). Glutathione S-transferase (GST), a phase II antioxidant enzyme is induced by oxidative stress generated by drugs and reactive oxidants. The present study was undertaken to evaluate the association of GSTM1, T1 and P1 polymorphisms with the outcome of CRT treatment in CC patients.

METHODS

A total of 227 cervical cancer patients with stages IIB-IIIB treated with the same chemoradiotherapy regimen were enrolled and genotyped for GSTM1, T1 and P1 gene polymorphisms by multiplex polymerase chain reaction (mPCR) and PCR-restriction fragment length polymorphism (PCR-RFLP). Overall survival was evaluated using Kaplan-Meier survival function and Cox proportional hazards model. All data were analyzed using SPSS (version 21.0).

RESULTS

Stratified analysis showed that GSTM1 null (M1-) genotype was associated with a significantly better survival among patients with stage IIB cervical cancer (log-rank P = 0.004) than cases with stage IIIA/IIIB. Death and recurrence were significantly higher in patients with GSTM1 present genotype (M1+) (P = 0.037 and P = 0.003 respectively) and those with M1- showed reduced hazard of death with an adjusted hazard ratio 'HR' of 0.47 (95% CI, 0.269-0.802, P = 0.006). Women with M1- genotype as well as in combination with GSTT1 null (T1-), GSTP1 (AG+GG) and GSTT1 null/GSTP1 (AG+GG) showed better survival and also reduced risk of death (HR = 0.31, P = 0.016; HR = 0.45, P = 0.013; HR = 0.31, P = 0.02 respectively).

CONCLUSIONS

To the best of our knowledge, this is the first study to correlate the association of GSTM1, T1 and P1 gene polymorphisms with treatment outcome of CRT treated CC patients. Our results suggested that individuals with GSTM1 null genotype and in combination with GSTT1 null and GSTP1 (AG+GG) had a survival advantage. Such genetic studies may provide prognostic information in CRT treated CC patients.

Influences of ERCC1, ERCC2, XRCC1, GSTP1, GSTT1, and MTHFR polymorphisms on clinical outcomes in gastric cancer patients treated with EOF chemotherapy

This study investigated the associations between genetic polymorphisms of six genes involved in DNA repair, detoxification pathways, and fluoropyrimidine metabolism and clinical outcomes in MGC patients receiving EOF treatment. This retrospective study included 108 Chinese MGC patients receiving EOF as first-line chemotherapy. Nine single nucleotide polymorphisms (SNPs) of six genes (ERCC1 rs2298881, ERCC2 rs13181 and rs1799793, XRCC1 rs25487 and rs25489, GSTP1 rs1695, GSTT1 rs2266637, and MTHFR rs1801133 and rs1801131) were genotyped, and the associations between each SNP and clinical outcome were analyzed. XRCC1 rs25487 A allele was significantly associated with progression disease (PD) to EOF (p = 0.002), and patients with AA genotype had significantly poorer progression-free survival (PFS) (p = 0.001) and overall survival (OS) (p = 0.041) compared with patients with the G allele (GG + GA). ERCC2 rs13181 G allele was significantly associated with PD (p = 0.026), and G carriers (GG + GT) tended to have poorer PFS (p = 0.092) than TT homozygotes. ERCC2 rs1799793 GA genotype was associated with unfavorable PFS (p = 0.034) and a tendency toward poorer OS (p = 0.090) compared with GG homozygotes. Patients were categorized as either good (0 risk factors) or poor risk (≥1 unfavorable SNPs) using a prognostic index based on XRCC1 rs25487 AA, ERCC2 rs13181 (GG + GT), and ERCC2 rs1799793 GA genotypes, with median OS and PFS of 534 days, 281 days (p = 0.009) and 206 days, and 123 days (p < 0.001), respectively. These results suggest that the prognostic index comprising XRCC1 rs25487, ERCC2 rs13181, and rs1799793 polymorphisms may be a useful predictor of clinical outcomes in MGC treated with EOF.

Prognostic significance of the mRNA expression of ERCC1, RRM1, TUBB3 and TYMS genes in patients with non-small cell lung cancer

The present study aimed to investigate the prognostic value of excision repair cross-complementing 1 (ERCC1), ribonucleotide reductase subunit M1 (RRM1), class III β-tubulin (TUBB3) and thymidylate synthase (TYMS) in patients with non-small cell lung cancer (NSCLC) receiving platinum-based adjuvant chemotherapy. The mRNA expression of these genes was assessed in 72 tumor tissue samples obtained following surgery, using multiplex branched-DNA technology. Subsequent to surgery, all 72 patients with NSCLC were treated with platinum-based chemotherapy. The expression of these five genes was analyzed and the correlation with clinical characteristics and patient survival was investigated. Among the 72 samples, the incidence rate of mRNA expression of ERCC1 was 38.9% (28/72), RRM1 was 55.6% (40/72), TUBB3 was 47.2% (34/72) and TYMS was 62.5% (45/72). The incidence rate of ERCC1 expression in adenocarcinoma (34.2%) was significantly lower than that in non-adenocarcinoma (44.1%; P<0.05). Furthermore, the incidence rates of TYMS and TUBB3 expression in the high-median differentiation tissue samples were significantly lower than those in the low differentiation tissue samples (P<0.05). When the correlation of gene expression and patient survival was analyzed, high expression of ERCC1, RRM1, TUBB3 or TYMS was found to be associated with poor prognosis (P<0.001, P=0.001, P=0.001 and P=0.001, respectively). ERCC1, RRM1, TUBB3 and TYMS are key factors involved in survival following surgical treatment in patients with NSCLC. The mRNA expression of these genes may have prognostic value for patients with NSCLC treated with platinum-based chemotherapy.

Methyl-methanesulfonate sensitivity 19 expression is associated with metastasis and chemoradiotherapy response in esophageal cancer

AIM: To investigate the clinical significance of methyl-methanesulfonate sensitivity 19 (MMS19) expression in esophageal squamous cell carcinoma (ESCC).

METHODS: Between June 2008 and May 2013, specimens from 103 patients who underwent endoscopic biopsy for the diagnosis of ESCC at the endoscopy center of Sun Yat-Sen University Cancer Center were collected; 52 matched-normal esophageal squamous epithelium samples were biopsied as controls. MMS19 protein expression was measured by immunohistochemistry. Of the 103 cases of ESCC, 49 received radical surgery following neoadjuvant chemoradiotherapy consisting of concurrent radiation in a total dose of 40 Gy and two cycles of chemotherapy with vinorelbine and cisplatin. Relationships between MMS19 expression, clinicopathologic characteristics and chemoradiotherapy response were analyzed.

RESULTS: The MMS19 protein could be detected in both the cytoplasm and nucleus of most specimens. High cytoplasmic expression of MMS19 was detected in 63.1% of ESCC samples, whereas high nuclear expression of MMS19 was found in 35.0%. High cytoplasmic MMS19 expression was associated with regional lymph node metastases (OR = 11.3, 95%CI: 2.3-54.7; P < 0.001) and distant metastases (OR = 13.1, 95%CI: 1.7-103.0; P = 0.002). Furthermore, high cytoplasmic MMS19 expression was associated with a response of ESCC to chemoradiotherapy (OR = 11.5, 95%CI: 3.0-44.5; P < 0.001), with a high cytoplasmic MMS19 expression rates in 79.3% and 25.0% of patients from the good chemoradiotherapy response group and poor response group, respectively. Nuclear MMS19 expression did not show any significant association with clinicopathologic characteristics or chemoradiotherapy response in ESCC.

CONCLUSION: The results of our preliminary study suggest that MMS19 may be a potential new predictor of metastasis and chemoradiotherapy response in ESCC.

DNA repair gene ERCC1 C118T polymorphism predicts sensitivity of recurrent esophageal cancer to radiochemotherapy in a Chinese population

Background

DNA repair gene polymorphisms could alter DNA repair capacity and therefore associate with tumor sensitivity to radiochemotherapy. This study assessed excision repair cross-complementing group 1 (ERCC1) C118T and X-ray cross-complementing group 1 (XRCC1) G399A single-nucleotide polymorphisms in esophageal patients for an association with sensitivity to radiation and chemotherapy.

Methods

Esophageal squamous cell carcinoma patients (n = 118) who relapsed after surgery were enrolled for assessment of ERCC1 C118T and XRCC1 G399A polymorphisms by direct DNA sequencing.

Results

The response rate of treatments was 48.30%: 14 complete response (CR, 11.86%), 43 partial response (PR, 36.44%), 49 stable disease (SD, 41.53%), and 12 progressive disease (PD, 10.17%). ERCC1 C118T was significantly associated with treatment response (C/T vs. C/C + T/T, odds ratio [OR] = 6.035, 95% confidence interval [CI]: 2.114–17.226, P = 0.001) after adjusting for other clinicopathological factors. Patients carrying the C/T genotype had significantly prolonged overall survival (OS) compared with C/C and T/T (median OS 43.00 vs. 27.00, P = 0.027). Multivariate Cox regression showed that a response was only an independent prognostic factor for OS (CR + PR vs. SD+PD, HR = 0.471 95% CI 0.269–0.826, P = 0.009). Grade III and IV adverse events occurred in 12 of 118 patients (10.17%). Only concurrent radiochemotherapy significantly increased these adverse events (OR = 26.529, 95% CI 2.312–304.389, P = 0.008).

Conclusion

ERCC1 C118T could be a predictive factor for the response to radiotherapy and chemotherapy, but not a prognostic factor for OS in esophageal cancer patients after surgery.

ERCC1 SNPs as Potential Predictive Biomarkers in Non-Small Cell Lung Cancer Patients Treated With Platinum-Based Chemotherapy

Polymorphisms in ERCC1, XPD, and XRCC1 were examined for (a) association with the clinical outcome of 107 non-small cell lung cancer patients receiving front-line platinum-based chemotherapy, and (b) correlation with the ERCC1 mRNA levels of 176 chemo-naive primary tumors. The ERCC1-C8092 allele and the number of ERCC1 polymorphic variants (C8092A and Asn118Asn) were associated with progression-free survival. In non-squamous histology, tumoral ERCC1 mRNA levels were lower in patients homozygous for ERCC1-C8092 as compared with the patients carrying the A allele (p = .024). These findings merit investigation in larger cohorts of patients treated with uniform regimens.

Prognostic value of ERCC1, ERCC2, XRCC1, and TP53 single nucleotide polymorphisms in patients with early-stage non-small cell lung cancer

Identification of biomarkers used for the prognostic evaluation of non-small cell lung cancer (NSCLC) patients is important. The aim of this study was to evaluate the potential prognostic value of XRCC1, ERCC1, ERCC2, and TP53 single nucleotide polymorphisms (SNPs) in completely resected NSCLC patients. In total, 130 patients, surgically treated for NSCLC between 2000 and 2012, were included. An analysis of SNPs from peripheral blood cells was performed by polymerase chain reaction. XRCC1 Arg399Gln, ERCC1 Asn118Asn, ERCC2 Lys751Gln, and TP53 Arg72Pro polymorphisms were evaluated in conjunction with clinical and pathological parameters and survival. Kaplan-Meier method and Cox regression analysis were used. Median age rate was 59.3, ranging between 36 and 78 years. Median relapse-free survival duration (RFS) was found as 46.2 months. In those with ERCC2 CC allele, median RFS was detected as 28.3 months (95 % confidence interval (CI), 20.8-35.8), 46.9 months in those with CT heterozygous (95 % CI, 18.6-75.2), and 80.1 months for those with TT mutant allel (95 % CI, 33.0-127.2). Median RFS was seen to be longer in mutant group and also statistically significant (P = 0.018). Additionally, upon evaluating CC normal group with CT + TT alleles including mutant alleles, median RFS was found as 56.5 months (95 % CI, 24.6-88.4) in CT + TT group, and this was statistically significant (P = 0.005) Also, median RFS was 15.1 months in those including ERCC2 CC allele and 56.5 months in CT + TT allele in the group with no adjuvant treatment (P = 0.001). In conclusion, our study showed that ERCC2/XPD polymorphism is an independent prognostic factor in operated NSCLC patients, and these findings should be supported with prospective studies.

Heterogeneity of excision repair cross-complementation group 1 gene expression in non-small-cell lung cancer patients

Excision repair cross-complementation group 1 (ERCC1) gene expression analysis is currently used widely in the molecular diagnosis of cancer. According to numerous studies, ERCC1 gene expression correlates with overall survival and effectiveness of chemotherapy with platinum agents. However, the degree of this correlation differs among various studies, with certain authors reporting a complete lack of such a correlation. These contradictions may be attributed to a number of factors, including the heterogeneity of the tumor tissue. In this study, we attempted to assess the degree of genetic heterogeneity exhibited by tissue samples obtained from non-small-cell lung cancer (NSCLC) through the expression of the ERCC1 gene. This study included 25 samples of tumor tissue from patients with a morphologically confirmed NSCLC diagnosis. A total of three randomized sections of each specimen were used. The ERCC1 gene expression was assessed by quantitative polymerase chain reaction (qPCR) in the TaqMan format. When planning the experiment and analysis of qPCR data, the MIQE guidelines were taken into consideration. We established that the coefficient of variation of the relative level of ERCC1 gene expression in the majority of the samples exceeded 33% (P<0.05), indicating the significant heterogeneity of the sample. We also demonstrated that the degree of heterogeneity of the tumor tissue is largely dependent on disease stage.

Can pharmacogenetics explain efficacy and safety of cisplatin pharmacotherapy?

Several recent pharmacogenetic studies have investigated the variability in both outcome and toxicity in cisplatin-based therapies. These studies have focused on the genetic variability of therapeutic targets that could affect cisplatin response and toxicity in diverse type of cancer including lung, gastric, ovarian, testicular, and esophageal cancer. In this review, we seek to update the reader in this area of investigation, focusing primarily on DNA reparation enzymes and cisplatin metabolism through Glutathione S-Transferases (GSTs). Current evidence indicates a potential application of pharmacogenetics in therapeutic schemes in which cisplatin is the cornerstone of these treatments. Therefore, a collaborative effort is required to study these molecular characteristics in order to generate a genetic panel with clinical utility.

DNA repair gene polymorphisms and clinical outcome of patients with primary small cell carcinoma of the esophagus

Polymorphisms in DNA repair genes impact on the synthesis of DNA repair proteins that are crucial to the repair of DNA damages induced by chemotherapy and radiotherapy. We retrospectively examined whether there was an association between the selected six single nucleotide polymorphisms (SNPs) of five DNA repair genes (PARP1-Val762Ala, XRCC1-Arg194Trp, XRCC1-Arg399Gln, XPC-Lys939Gln, BRCA1-Lys1183Arg, and BRCA2-Asn372His) and the clinical outcome of patients with primary small cell carcinoma of esophagus (SCCE), and it showed that the median progression-free survival (PFS) and the overall survival (OS) were 11.8 versus 9.7 months (P = 0.041) and 17.4 versus 14.8 months (P = 0.032) for patients carrying the variant allele (T/C + C/C) and the wild-type allele (T/T) of PARP1-Val762Ala polymorphism, respectively. However, no statistical significance was observed in the other five polymorphic loci (P > 0.05). When these six SNPs were combined, however, patients with at least three variant genotypes had significantly longer PFS and OS compared with those carrying less than three variant genotypes (P = 0.009 and P = 0.007, respectively). The presence of at least three polymorphic variants in certain DNA repair genes may impact on patient survival and could be a potential genomic predictor of clinical response to DNA-damaging treatment in SCCE patients.

The role of DNA repair pathways in cisplatin resistant lung cancer

Platinum chemotherapeutic agents such as cisplatin are currently used in the treatment of various malignancies such as lung cancer. However, their efficacy is significantly hindered by the development of resistance during treatment. While a number of factors have been reported that contribute to the onset of this resistance phenotype, alterations in the DNA repair capacity of damaged cells is now recognised as an important factor in mediating this phenomenon. The mode of action of cisplatin has been linked to its ability to crosslink purine bases on the DNA, thereby interfering with DNA repair mechanisms and inducing DNA damage. Following DNA damage, cells respond by activating a DNA-damage response that either leads to repair of the lesion by the cell thereby promoting resistance to the drug, or cell death via activation of the apoptotic response. Therefore, DNA repair is a vital target to improving cancer therapy and reduce the resistance of tumour cells to DNA damaging agents currently used in the treatment of cancer patients. To date, despite the numerous findings that differential expression of components of the various DNA repair pathways correlate with response to cisplatin, translation of such findings in the clinical setting are still warranted. The identification of alterations in specific proteins and pathways that contribute to these unique DNA repair pathways in cisplatin resistant cancer cells may potentially lead to a renewed interest in the development of rational novel therapies for cisplatin resistant cancers, in particular, lung cancer.

Genome-wide association study of survival in early-stage non-small cell lung cancer

BACKGROUND

Lung cancer, especially non-small cell lung cancer (NSCLC), is the leading cause of cancer-related deaths all over the world. Studies have indicated that molecular biomarkers, including genetic variants, may provide additional values for the targeted treatments and clinical outcomes of NSCLC patients. To better understand the effects of molecular biomarkers on the treatment of NSCLC, we conducted a genome-wide analysis to investigate the prognostic implications of genetic variants in early-stage NSCLC patients with surgery.

METHODS

A genome wide scan of 906,703 single-nucleotide polymorphisms (SNPs) was conducted in a cohort with 365 early-stage NSCLC patients with surgery, followed by a fast-track replication in another independent cohort of 327 NSCLC patients from Nanjing, China. Cox models were used to screen and validate significant SNPs associated with the overall survival of early-stage NSCLC patients.

RESULTS

We found that rs10023113 in calcium/calmodulin-dependent protein kinase II delta (CAMK2D) was consistently associated with survival of early-stage NSCLC in the GWAS scan and the replication cohort [GWAS scan: hazard ratio (HR) 2.84; 95 % confidence interval (CI) 1.90-4.23, P = 1.29 × 10(-6); replication cohort: HR 2.19, 95 % CI 1.15-4.21, P = 1.80 × 10(-2)]. When combining all the patients, the results showed that the variant allele of rs10023113 was significantly associated with poor prognosis of early-stage NSCLC with P value of 3.40 × 10(-7) (HR 2.30, 95 % CI 1.67-3.17).

CONCLUSIONS

These findings suggest that CAMK2D rs10023113 may be a potentially prognostic marker for overall survival of early-stage NSCLC patients in Chinese population.

hMSH2 expression is associated with paclitaxel resistance in ovarian carcinoma, and inhibition of hMSH2 expression in vitro restores paclitaxel sensitivity

The objective of the present study was to investigate the association between paclitaxel resistance, gene copy number, and gene expression in ovarian carcinoma, and to restore paclitaxel sensitivity in a paclitaxel-resistant ovarian carcinoma cell line by using hMSH2-targeting siRNA. Paclitaxel-resistant ovarian carcinoma cell lines OC3/TAX300 and OC3/TAX50 and their parental cell lines were analyzed by comparative genomic hybridization, and the expression levels of hMSH2 in ovarian carcinoma cell lines and tissues were determined. An siRNA targeted to hMSH2 mRNA was used to transfect a paclitaxel-resistant cell line. We assessed the morphological features, proliferation, and susceptibility to apoptosis of the transfected cells after paclitaxel treatment. Chromosome 2p21 (gene locus of hMSH2) was amplified in OC3/TAX300 cells. hMSH2 was overexpressed in 93.9 and 47.6% of paclitaxel-treated and untreated ovarian carcinoma tissue samples (P=0.0001), respectively. hMSH2 was overexpressed in 93.3 and 54.2% of low-differentiated and moderate-to-highly differentiated ovarian carcinoma tissue samples (P=0.0008), respectively. hMSH2 expression was inhibited in the OC3/TAX300 cells transfected with hMSH2 siRNA. hMSH2 siRNA increased paclitaxel sensitivity, inhibited OC3/TAX300 cell proliferation (G2/M arrest), and increased susceptibility to apoptosis. hMSH2 expression was upregulated in ovarian carcinoma cell lines and tissues after paclitaxel treatment. hMSH2 overexpression is related to paclitaxel resistance and poor prognosis. Inhibition of hMSH2 expression in vitro restores paclitaxel sensitivity in paclitaxel‑resistant ovarian carcinoma cell lines and indicates a new direction in adjuvant therapy for ovarian carcinoma.

Pharmacogenetics research on chemotherapy resistance in colorectal cancer over the last 20 years

During the past two decades the first sequencing of the human genome was performed showing its high degree of inter-individual differentiation, as a result of large international research projects (Human Genome Project, the 1000 Genomes Project International HapMap Project, and Programs for Genomic Applications NHLBI-PGA). This period was also a time of intensive development of molecular biology techniques and enormous knowledge growth in the biology of cancer. For clinical use in the treatment of patients with colorectal cancer (CRC), in addition to fluoropyrimidines, another two new cytostatic drugs were allowed: irinotecan and oxaliplatin. Intensive research into new treatment regimens and a new generation of drugs used in targeted therapy has also been conducted. The last 20 years was a time of numerous in vitro and in vivo studies on the molecular basis of drug resistance. One of the most important factors limiting the effectiveness of chemotherapy is the primary and secondary resistance of cancer cells. Understanding the genetic factors and mechanisms that contribute to the lack of or low sensitivity of tumour tissue to cytostatics is a key element in the currently developing trend of personalized medicine. Scientists hope to increase the percentage of positive treatment response in CRC patients due to practical applications of pharmacogenetics/pharmacogenomics. Over the past 20 years the clinical usability of different predictive markers has been tested among which only a few have been confirmed to have high application potential. This review is a synthetic presentation of drug resistance in the context of CRC patient chemotherapy. The multifactorial nature and volume of the issues involved do not allow the author to present a comprehensive study on this subject in one review.

MicroRNA binding site polymorphisms as biomarkers in cancer management and research

MicroRNAs (miRNAs) are important regulators of eukaryotic gene expression. They have been implicated in a broad range of biological processes, and miRNA-related genetic alterations probably underlie several human diseases. Single nucleotide polymorphisms of transcripts may modulate the posttranscriptional regulation of gene expression by miRNAs and explain interindividual variability in cancer risk and in chemotherapy response. On the basis of recent association studies published in the literature, the present review mainly summarizes the potential role of miRNAs as molecular biomarkers for disease susceptibility, diagnosis, prognosis, and drug-response prediction in tumors. Many clues suggest a role for polymorphisms within the 3' untranslated regions of KRAS rs61764370, SET8 rs16917496, and MDM4 rs4245739 as SNPs in miRNA binding sites highly promising in the biology of human cancer. However, more studies are needed to better characterize the composite spectrum of genetic determinants for future use of markers in risk prediction and clinical management of diseases, heading toward personalized medicine.

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.