Enhanced nucleotide excision repair capacity in lung cancer cells by preconditioning with DNA-damaging agents

Relevance of Comet Assay and Phosphorylated-Hsp90α in Cancer Patients' Peripheral Blood Leukocytes as Tools to Assess Cisplatin-based Chemotherapy Clinical Response and Disease Outcome

Cisplatin (cPt) is a commonly used treatment for solid tumors. The main target of its cytotoxicity is the DNA molecule, which makes the DNA damage response (DDR) crucial for cPt-based chemotherapy. Therefore, it is essential to identify biomarkers that can accurately predict the individual clinical response and prognosis. Our goal was to assess the usefulness of alkaline comet assay and immunocytochemical staining of phosphorylated Hsp90α (p-Hsp90α), γH2AX, and 53BP1 as predictive/prognostic markers. Pre-chemotherapy peripheral blood leukocytes were exposed to cPt in vitro and collected at 0, 24 (T24), and 48 (T48) hr post-drug removal. Healthy subjects were also included. Baseline DNA damage was elevated in cancer patients (variability between individuals was observed). After cPt, patients showed increased γH2AX foci/nucleus (T24 and T48). Both in healthy persons and patients, the nuclear p-Hsp90α and N/C (nuclear/cytoplasmic) ratio augmented (T24), decreasing at T48. Favorable clinical response was associated with high DNA damage and p-Hsp90α N/C ratio following cPt. For the first time, p-Hsp90α significance as a predictive marker is highlighted. Post-cPt-DNA damage was associated with longer disease-free survival and overall survival. Our findings indicate that comet assay and p-Hsp90α (a marker of DDR) would be promising prognostic/predictive tools in cP-treated cancer patients.

Circadian control of cisplatin-DNA adduct repair and apoptosis in culture cells

Cisplatin, a widely prescribed chemotherapeutic agent for treating solid tumors, induces DNA adducts and activates cellular defense mechanisms, including DNA repair, cell cycle checkpoint control, and apoptosis. Considering the circadian rhythmicity displayed by most chemotherapeutic agents and their varying therapeutic efficacy based on treatment timing, our study aimed to investigate whether the circadian clock system influences the DNA damage responses triggered by cisplatin in synchronized cells. We examined the DNA damage responses in circadian-synchronized wild-type mouse embryonic fibroblasts (WT-MEF; clock-proficient cells), cryptochrome1 and 2 double knock-out MEF (CRYDKO; clock-deficient cells), and mouse hepatocarcinoma Hepa1c1c7 cells. Varying the treatment time resulted in a significant difference in the rate of platinum-DNA adduct removal specifically in circadian-synchronized WT-MEF, while CRYDKO did not exhibit such variation. Moreover, diurnal variation in other DNA damage responses, such as cell cycle checkpoint activity indicated by p53 phosphorylation status and apoptosis measured by DNA break frequency, was observed only in circadian-synchronized WT-MEF, not in CRYDKO or mouse hepatocarcinoma Hepa1c1c7 cells. These findings highlight that the DNA damage responses triggered by cisplatin are indeed governed by circadian control exclusively in clock-proficient cells. This outcome bears potential implications for enhancing or devising chronotherapy approaches for cancer patients.

The XPA Protein-Life under Precise Control

Nucleotide excision repair (NER) is a central DNA repair pathway responsible for removing a wide variety of DNA-distorting lesions from the genome. The highly choreographed cascade of core NER reactions requires more than 30 polypeptides. The xeroderma pigmentosum group A (XPA) protein plays an essential role in the NER process. XPA interacts with almost all NER participants and organizes the correct NER repair complex. In the absence of XPA's scaffolding function, no repair process occurs. In this review, we briefly summarize our current knowledge about the XPA protein structure and analyze the formation of contact with its protein partners during NER complex assembling. We focus on different ways of regulation of the XPA protein's activity and expression and pay special attention to the network of post-translational modifications. We also discuss the data that is not in line with the currently accepted hypothesis about the functioning of the XPA protein.

A Preclinical Study to Repurpose Spironolactone for Enhancing Chemotherapy Response in Bladder Cancer

Neoadjuvant chemotherapy (NAC) followed by radical cystectomy is the standard-of-care for patients with muscle-invasive bladder cancer (MIBC). Defects in nucleotide excision repair (NER) are associated with improved responses to NAC. Excision Repair Cross-Complementation group 3 (ERCC3) is a key component of NER process. No NER inhibitors are available for treating patients with bladder cancer. We have developed an ex vivo cell-based assay of 6-4 pyrimidine-pyrimidinone (6-4PP) removal as a surrogate measure of NER capacity in human bladder cancer cell lines. The protein expression of ERCC3 was examined in human MIBC specimens and cell lines. Small molecule inhibitors were screened for NER inhibition in bladder cancer cell lines. Spironolactone was identified as a potent NER inhibitor. Combined effects of spironolactone with chemo-drugs were evaluated in vitro and in vivo. The efficacy between platinum and spironolactone on cytotoxicity was determined by combination index. A correlation between NER capacity and cisplatin sensitivity was demonstrated in a series of bladder cancer cell lines. Further, siRNA-mediated knockdown of ERCC3 abrogated NER capacity and enhanced cisplatin cytotoxicity. Spironolactone inhibited ERCC3 protein expression, abrogated NER capacity, and increased platinum-induced cytotoxicity in bladder cancer cells in vivo and in patient-derived organoids. Moreover, spironolactone exhibited the potential synergism effects with other clinical chemotherapy regimens in bladder cancer cell lines. Our data support the notion of repurposing spironolactone for improving the chemotherapy response of NAC in patients with MIBC. Further clinical trials are warranted to determine the safety and efficacy of spironolactone in combination with chemotherapy.

Role of caveolin-1 as a biomarker for radiation resistance and tumor aggression in lung cancer

Radiation therapy plays a major role in the treatment of lung cancer patients. However, cancer cells develop resistance to radiation. Tumor radioresistance is a complex multifactorial mechanism which may be dependent on DNA damage and repair, hypoxic conditions inside tumor microenvironment, and the clonal selection of radioresistant cells from the heterogeneous tumor site, and it is a major cause of treatment failure in non-small cell lung cancer (NSCLC). In the present investigation caveolin-1 (CAV-1) has been observed to be highly expressed in radiation resistant A549 lung cancer cells. CRISPR-Cas9 knockout of CAV-1 reverted the cells to a radio sensitive phenotype. In addition, CAV-1 overexpression in parental A549 cells, led to radiation resistance. Further, gene expression analysis of A549 parental, radiation resistant, and caveolin-1 overexpressed cells, exhibited overexpression of DNA repair genes RAD51B, RAD18, SOX2 cancer stem cell marker, MMPs, mucins and cytoskeleton proteins in resistant and caveolin-1 over expressed A549 cells, as compared to parental A549 cells. Bioinformatic analysis shows upregulation of BRCA1, Nuclear Excision DNA repair, TGFB and JAK/STAT signaling pathways in radioresistant and caveolin-1 overexpressed cells, which may functionally mediate radiation resistance. Immunohistochemistry data demonstrated heterogeneous expression of CAV-1 gene in human lung cancer tissues, which was analogous to its enhanced expression in human lung cancer cell line model and mouse orthotopic xenograft lung cancer model. Also, TCGA PanCancer clinical studies have demonstrated amplification, deletions and missense mutation in CAV-1 gene in lung cancer patients, and that CAV-1 alteration has been linked to poor prognosis, and poor survival in lung cancer patients. Interestingly, we have also optimized ELISA assay to measure caveolin-1 protein in the blood of A549 radiation resistant human xenograft preclinical mouse model and discovered higher level of caveolin-1 (950 pg/ml) in tumor bearing animals treated with radiation, as compared to xenograft with radiosensitive lung cancer cells (450 pg/ml). Thus, we conclude that caveolin-1 is involved in radio-resistance and contributes to tumor aggression, and it has potential to be used as prognostic biomarker for radiation treatment response, and tumor progression for precision medicine in lung cancer patients.

Targeting the Interplay between HDACs and DNA Damage Repair for Myeloma Therapy

Multiple myeloma (MM) is a malignancy of terminally differentiated plasma cells, and accounts for 10% of all hematologic malignancies and 1% of all cancers. MM is characterized by genomic instability which results from DNA damage with certain genomic rearrangements being prognostic factors for the disease and patients’ clinical response. Following genotoxic stress, the evolutionary conserved DNA damage response (DDR) is activated and, in turn, coordinates DNA repair with cell-cycle events. However, the process of carcinogenesis cannot be attributed only to the genetic alterations, but also involves epigenetic processes. Regulation of expression and activity of key players in DNA repair and checkpoint proteins are essential and mediated partly by posttranslational modifications (PTM), such as acetylation. Crosstalk between different PTMs is important for regulation of DNA repair pathways. Acetylation, which is mediated by acetyltransferases (HAT) and histone deacetylases (HDAC), not only affects gene expression through its modulation of histone tails but also has recently been implicated in regulating non-histone proteins. Currently, several HDAC inhibitors (HDACi) have been developed both in pre-clinical and clinical studies, with some of them exhibiting significant anti-MM activities. Due to reversibility of epigenetic changes during the evolutionary process of myeloma genesis, the potency of epigenetic therapies seems to be of great importance. The aim of the present paper is the summary of all data on the role of HDACi in DDR, the interference with each DNA repair mechanism and the therapeutic implications of HDACi in MM.

Circadian Rhythm of NER and ATR Pathways

Genomic integrity is constantly insulted by solar ultraviolet (UV) radiation. Adaptative cellular mechanisms called DNA damage responses comprising DNA repair, cell cycle checkpoint, and apoptosis, are believed to be evolved to limit genomic instability according to the photoperiod during a day. As seen in many other key cellular metabolisms, genome surveillance mechanisms against genotoxic UV radiation are under the control of circadian clock systems, thereby exhibiting daily oscillations in their catalytic activities. Indeed, it has been demonstrated that nucleotide excision repair (NER), the sole DNA repair mechanism correcting UV-induced DNA photolesions, and ataxia–telangiectasia-mutated and Rad3-related (ATR)-mediated cell cycle checkpoint kinase are subjected to the robust control of the circadian clock. The molecular foundation for the circadian rhythm of UV-induced DNA damage responses in mammalian cells will be discussed.

Effects of in vivo treatment of mice with sulforaphane on repair of DNA pyridyloxylbutylation

The phytochemical sulforaphane (SF) has gained interest for its apparent association with reduced cancer risk and other cytoprotective properties, at least some of which are attributed to activation of the transcription factor Nrf2. Repair of bulky DNA adducts is important for mitigating carcinogenesis from exogenous DNA damaging agents, but it is unknown whether in vivo treatment with SF affects adduct repair. At 12 h following a single oral dose of 100 mg/kg SF, an almost doubling in activity for repair of pyridyloxobutylated DNA was observed in CD-1 mouse liver nuclear extracts, but not in lung extracts. This change at 12 h in repair activity was preceded by the induction of Nrf2-regulated genes but not accompanied by changes in levels of the specific nucleotide excision repair (NER) proteins XPC, XPA, XPB and p53 or in binding of hepatic XPC, XPA and XPB to damaged DNA. SF also did not significantly alter histone deacetylase activity as measured by acetylated histone H3 levels, or stimulate formation of γ-H2A.X, a marker of DNA damage. A significant reduction in oxidative DNA damage, as measured by 8-OHdG (a biomarker of oxidative DNA damage), was observed only in DNA from the lungs of SF-treated mice 3 h post-dosing. These results suggest that the ability of SF to increase bulky adduct repair activity is organ-selective and is consistent with activation of the Nrf2 signaling pathway.

SIRT2 protects peripheral neurons from cisplatin-induced injury by enhancing nucleotide excision repair

Platinum-based chemotherapy-induced peripheral neuropathy is one of the most common causes of dose reduction and discontinuation of life-saving chemotherapy in cancer treatment; it often causes permanent impairment of quality of life in cancer patients. The mechanisms that underlie this neuropathy are not defined, and effective treatment and prevention measures are not available. Here, we demonstrate that SIRT2 protected mice against cisplatin-induced peripheral neuropathy (CIPN). SIRT2 accumulated in the nuclei of dorsal root ganglion sensory neurons and prevented neuronal cell death following cisplatin treatment. Mechanistically, SIRT2, an NAD+-dependent deacetylase, protected neurons from cisplatin cytotoxicity by promoting transcription-coupled nucleotide excision repair (TC-NER) of cisplatin-induced DNA cross-links. Consistent with this mechanism, pharmacological inhibition of NER using spironolactone abolished SIRT2-mediated TC-NER activity in differentiated neuronal cells and protection of neurons from cisplatin-induced cytotoxicity and CIPN in mice. Importantly, SIRT2's protective effects were not evident in lung cancer cells in vitro or in tumors in vivo. Taken together, our results identified SIRT2's function in the NER pathway as a key underlying mechanism of preventing CIPN, warranting future investigation of SIRT2 activation-mediated neuroprotection during platinum-based cancer treatment.

XPA: DNA Repair Protein of Significant Clinical Importance

The nucleotide excision repair (NER) pathway is activated in response to a broad spectrum of DNA lesions, including bulky lesions induced by platinum-based chemotherapeutic agents. Expression levels of NER factors and resistance to chemotherapy has been examined with some suggestion that NER plays a role in tumour resistance; however, there is a great degree of variability in these studies. Nevertheless, recent clinical studies have suggested Xeroderma Pigmentosum group A (XPA) protein, a key regulator of the NER pathway that is essential for the repair of DNA damage induced by platinum-based chemotherapeutics, as a potential prognostic and predictive biomarker for response to treatment. XPA functions in damage verification step in NER, as well as a molecular scaffold to assemble other NER core factors around the DNA damage site, mediated by protein–protein interactions. In this review, we focus on the interacting partners and mechanisms of regulation of the XPA protein. We summarize clinical oncology data related to this DNA repair factor, particularly its relationship with treatment outcome, and examine the potential of XPA as a target for small molecule inhibitors.

Posttranscriptional control of the replication stress response via TTP-mediated Claspin mRNA stabilization

ATR and CHK1 play key roles in the protection and recovery of the stalled replication forks. Claspin, an adaptor for CHK1 activation, is essential for DNA damage signaling and efficient replication fork progression. Here, we show that tristetraprolin (TTP), an mRNA-binding protein, can modulate the replication stress response via stabilization of Claspin mRNA. TTP depletion compromised specifically in the phosphorylation of CHK1, but not p53 or H2AX among other ATR substrates, and produced CHK1-defective replication phenotypes including accumulation of stalled replication forks. Importantly, the expression of siRNA-resistant TTP in TTP-deficient cells restored CHK1 phosphorylation and reduced the number of stalled replication forks as close to the control cells. Besides, we found that TTP was required for efficient replication fork progression even in the absence of exogenous DNA damage in a Claspin-dependent manner. Mechanistically, TTP was able to bind to the 3'-untranslated region of Claspin mRNA to increase the stability of Claspin mRNA which eventually contributed to the subsequent ATR-CHK1 activation upon DNA damage. Taken together, our results revealed an intimate link between TTP-dependent Claspin mRNA stability and ATR-CHK1-dependent replication fork stability to maintain replication fork integrity and chromosomal stability.

DNA Oxidation and Excision Repair Pathways

The physiological impact of the aberrant oxidation products on genomic DNA were demonstrated by embryonic lethality or the cancer susceptibility and/or neurological symptoms of animal impaired in the base excision repair (BER); the major pathway to maintain genomic integrity against non-bulky DNA oxidation. However, growing evidence suggests that other DNA repair pathways or factors that are not primarily associated with the classical BER pathway are also actively involved in the mitigation of oxidative assaults on the genomic DNA, according to the corresponding types of DNA oxidation. Among others, factors dedicated to lesion recognition in the nucleotide excision repair (NER) pathway have been shown to play eminent roles in the process of lesion recognition and stimulation of the enzyme activity of some sets of BER factors. Besides, substantial bulky DNA oxidation can be preferentially removed by a canonical NER mechanism; therefore, loss of function in the NER pathway shares common features arising from BER defects, including cancer predisposition and neurological disorders, although NER defects generally are nonlethal. Here we discuss recent achievements for delineating newly arising roles of NER lesion recognition factors to facilitate the BER process, and cooperative works of BER and NER pathways in response to the genotoxic oxidative stress.

Sirtuin 1-mediated deacetylation of XPA DNA repair protein enhances its interaction with ATR protein and promotes cAMP-induced DNA repair of UV damage

Blunted melanocortin 1 receptor (MC1R) signaling promotes melanocyte genomic instability in part by attenuating cAMP-mediated DNA repair responses, particularly nucleotide excision repair (NER), which recognizes and clears mutagenic photodamage. cAMP-enhanced NER is mediated by interactions between the ataxia telangiectasia-mutated and Rad3-related (ATR) and xeroderma pigmentosum complementation group A (XPA) proteins. We now report a critical role for sirtuin 1 (SIRT1) in regulating ATR-mediated phosphorylation of XPA. SIRT1 deacetylates XPA at residues Lys-63, Lys-67, and Lys-215 to promote interactions with ATR. Mutant XPA containing acetylation mimetics at residues Lys-63, Lys-67, and Lys-215 exhibit blunted UV-dependent ATR-XPA interactions even in the presence of cAMP signals. ATR-mediated phosphorylation of XPA on Ser-196 enhances cAMP-mediated optimization of NER and is promoted by SIRT1-mediated deacetylation of XPA on Lys-63, Lys-67, and Lys-215. Interference with ATR-mediated XPA phosphorylation at Ser-196 by persistent acetylation of XPA at Lys-63, Lys-67, and Lys-215 delays repair of UV-induced DNA damage and attenuates cAMP-enhanced NER. Our study identifies a regulatory ATR-SIRT1-XPA axis in cAMP-mediated regulation melanocyte genomic stability, involving SIRT1-mediated deacetylation (Lys-63, Lys-67, and Lys-215) and ATR-dependent phosphorylation (Ser-196) post-translational modifications of the core NER factor XPA.

Non-thermal plasma-induced apoptosis is modulated by ATR- and PARP1-mediated DNA damage responses and circadian clock

Non-thermal plasma (NTP) has been emerging as a potential cancer therapeutic. However, the practical use of NTP as a cancer therapy requires a better understanding of the precise mechanisms underlying NTP-induced DNA damage responses in order to achieve optimal efficacy. It has been shown that the addition of oxygen gas flow during NTP treatment (NTPO), when compared to NTP exposure alone, can induce a 2–3 fold greater generation of intracellular reactive oxygen species (ROS) in A549 cells. Here, we examined NTPO-induced DNA damage responses and found that NTPO generated a substantial number of genomic DNA lesions and breaks that activated ATR-mediated cell-cycle checkpoints. In addition, we discovered that NTPO-induced DNA lesions were primarily removed by base excision repair (BER) rather than by nucleotide excision repair (NER). Therefore, the inhibition of the BER pathway using a PARP1 inhibitor drastically induced the phosphorylation of γH2AX, and was followed by the programmed cell death of cancer cells. However, the knock-down of XPA, which inhibited the NER pathway, had no effect on NTPO-induced phosphorylation of γH2AX. Finally, in agreement with a recent report, we found a circadian rhythm of PARP1 activity in normal mouse embryonic fibroblasts that needed for cell viability upon NTPO treatment. Taken together, our findings provided an advanced NTP regimen for cancer treatment by combining NTPO treatment with chemical adjuvants for the inhibition of ATR- and PARP1-activated DNA damage responses, and circadian timing of treatment.

Programming of Cell Resistance to Genotoxic and Oxidative Stress

Different organisms, cell types, and even similar cell lines can dramatically differ in resistance to genotoxic stress. This testifies to the wide opportunities for genetic and epigenetic regulation of stress resistance. These opportunities could be used to increase the effectiveness of cancer therapy, develop new varieties of plants and animals, and search for new pharmacological targets to enhance human radioresistance, which can be used for manned deep space expeditions. Based on the comparison of transcriptomic studies in cancer cells, in this review, we propose that there is a high diversity of genetic mechanisms of development of genotoxic stress resistance. This review focused on possibilities and limitations of the regulation of the resistance of normal cells and whole organisms to genotoxic and oxidative stress by the overexpressing of stress-response genes. Moreover, the existing experimental data on the effect of such overexpression on the resistance of cells and organisms to various genotoxic agents has been analyzed and systematized. We suggest that the recent advances in the development of multiplex and highly customizable gene overexpression technology that utilizes the mutant Cas9 protein and the abundance of available data on gene functions and their signal networks open new opportunities for research in this field.

Interstrand Crosslink Repair as a Target for HDAC Inhibition

DNA interstrand crosslinks (ICLs) covalently connect complementary DNA strands. Consequently, DNA replication and transcription are hampered, DNA damage responses (DDR) are initiated, and cell death is triggered. Therefore, drugs inducing ICLs are effective against rapidly growing cancer cells. However, tumors engage a complicated enzymatic machinery to repair and survive ICLs. Several factors, including the post-translational acetylation/deacetylation of lysine residues within proteins, control this network. Histone deacetylases (HDACs) modulate the expression and functions of DNA repair proteins which remove ICLs and control the accessibility of chromatin. Accordingly, histone deacetylase inhibitors (HDACi) are small, pharmacologically and clinically relevant molecules that sensitize cancer cells to ICL inducers. We discuss the mechanism of ICL repair and targets of HDACi within this pathway.

Pharmacogenomics of platinum-based chemotherapy in non-small cell lung cancer: focusing on DNA repair systems

Drug therapy for non-small cell lung cancer consists mainly of platinum-based chemotherapy regimens. However, toxicity, drug resistance, and high risk of death have been seen in the clinic, which means there is a need for optimizing the use of medications. Platinum resistance could be mediated by a series of DNA repair pathways, and therefore, these pathways should be taken into account for optimizing drug using. The goal of pharmacogenomics is to elucidate genetic factors, such as DNA repair genes, which might underlie drug efficacy and effectiveness, and to improve therapeutic effects or guide personalized therapy as well. Here, we reviewed the current knowledge of pharmacogenomic data on DNA repair systems and examined whether they could be further translated into the clinic with evidence-based perspectives.

Transcriptional and Posttranslational Regulation of Nucleotide Excision Repair: The Guardian of the Genome against Ultraviolet Radiation

Ultraviolet (UV) radiation from sunlight represents a constant threat to genome stability by generating modified DNA bases such as cyclobutane pyrimidine dimers (CPD) and pyrimidine-pyrimidone (6-4) photoproducts (6-4PP). If unrepaired, these lesions can have deleterious effects, including skin cancer. Mammalian cells are able to neutralize UV-induced photolesions through nucleotide excision repair (NER). The NER pathway has multiple components including seven xeroderma pigmentosum (XP) proteins (XPA to XPG) and numerous auxiliary factors, including ataxia telangiectasia and Rad3-related (ATR) protein kinase and RCC1 like domain (RLD) and homologous to the E6-AP carboxyl terminus (HECT) domain containing E3 ubiquitin protein ligase 2 (HERC2). In this review we highlight recent data on the transcriptional and posttranslational regulation of NER activity.

A Platinum(IV) Anticancer Prodrug Targeting Nucleotide Excision Repair To Overcome Cisplatin Resistance

DNA damage response plays a key role not only in maintaining genome integrity but also in mediating the antitumor efficacy of DNA-damaging antineoplastic drugs. Herein, we report the rational design and evaluation of a Pt^IV anticancer prodrug inhibiting nucleotide excision repair (NER), one of the most pivotal processes after the formation of cisplatin-induced DNA damage that deactivates the drug and leads to drug resistance in the clinic. This dual-action prodrug enters cells efficiently and causes DNA damage while simultaneously inhibiting NER to promote apoptotic response. The prodrug is strongly active against the proliferation of cisplatin-resistant human cancer cells with an up to 88-fold increase in growth inhibition compared with cisplatin, and the prodrug is much more active than a mixture of cisplatin and an NER inhibitor. Our study highlights the importance of targeting downstream pathways after the formation of Pt-induced DNA damage as a novel strategy to conquer cisplatin resistance.

DNA repair gene polymorphisms in non-small-cell lung cancer patients treated with first-line platinum-containing chemotherapy

PURPOSE

Single nucleotide polymorphisms (SNPs) in the DNA repair genes are believed to contribute to the clinical outcome of patients receiving platinum-based chemotherapy. We investigated the impact of 2 SNPs of excision repair cross-complementation group 1 and 2 of xeroderma pigmentosum complementation group G on the outcome in patients with non-small-cell lung cancer (NSCLC) treated with platinum-based chemotherapy.

METHODS

Between October 2007 and March 2012, we collected 374 blood samples from consecutive patients registered in the TAILOR trial. Four SNPs (rs11615, rs3212986, rs17655, rs1047768) were genotyped using real-time polymerase chain reaction.

RESULTS

The rs11615 polymorphism was associated with histotype (p = 0.0123). No other correlations were found with clinical variables or with EGFR or KRAS mutational status. None of the SNPs had any impact on overall survival or progression-free survival.

CONCLUSIONS

The findings suggest that the investigated SNPs do not make any significant contribution to the outcome of NSCLC.