Lipid Metabolism Pathway Genes and Lung Cancer: ACADSB rs12220683G>C Is Associated with Better Survival Outcome in Patients with Non-Small Cell Lung Cancer.

INTRODUCTION: Altered lipid metabolism has been reported to be associated with prognosis in multiple cancers. This study aimed to investigate the association of polymorphisms in lipid metabolism pathway genes with survival outcomes in patients with surgically resected non-small cell lung cancer (NSCLC). METHODS: In total, 744 patients with surgically resected NSCLC (380 in the discovery cohort and 364 in the validation cohort) were included in this study. The association between 176 polymorphisms of lipid metabolism pathway genes and the clinical outcomes of NSCLC patients was analyzed. RESULTS: Among the polymorphisms investigated, ACADSB rs10902859G>A was associated with significantly better overall survival (OS) in the discovery, validation, and combined cohorts. ACADSB rs10902859G>A was located in the repressed region and had strong linkage disequilibrium (D' = 1.00 and r2 = 0.94), with rs12220683G>C located in the H3K4me3 peak region, which indicates the presence of active promoters. ACADSB rs12220683G>C was also associated with better OS in the discovery, validation, and combined cohorts (in a dominant model; adjusted hazard ratio [aHR] = 0.53, 95% confidence interval [CI] = 0.30-0.94, p = 0.03; aHR = 0.37, 95% CI = 0.15-0.89, p = 0.03; and aHR = 0.47, 95% CI = 0.29-0.75, p = 0.002, respectively). In vitro luciferase assay demonstrated that the promoter activity of ACADSB was significantly increased in the rs12220683 variant C allele compared with that in the wild G allele (p = 3 × 10-5). CONCLUSION: These results suggest that ACADSB rs12220683G>C increases promoter activity and that increased ACADSB expression may result in better OS in patients with surgically resected NSCLC.

Genetic Variants in Histone Modification Regions Predict Clinical Outcomes of Pemetrexed Chemotherapy in Lung Adenocarcinoma.

OBJECTIVE: This study was conducted to investigate the association between genetic variants in histone modification regions and clinical outcomes of PEM chemotherapy in patients with lung adenocarcinoma. METHODS: Potentially functional SNPs were selected using integrated analysis of ChIP-seq and RNA-seq. The associations of 279 SNPs with chemotherapy response and overall survival (OS) were analyzed in 314 lung adenocarcinoma patients who underwent PEM chemotherapy. RESULTS: Among the SNPs investigated, 18 were significantly associated with response to chemotherapy, while 28 with OS. Of these SNPs, rs549794A>G in an enhancer which is expected to regulate the expression of ribosomal protein S3 (RPS3) gene was significantly associated with both worse response to chemotherapy and worse OS (adjusted odds ratio = 0.59, 95% CI = 0.36-0.97, p = 0.04; adjusted hazard ratio = 1.44, 95% CI = 1.09-1.91, p = 0.01, respectively). Previous studies suggested that RPS3, a multi-functional protein with various extraribosomal activities, may play a role in chemotherapy resistance. Therefore, it is postulated that rs549794-induced change in the expression level of RPS3 may affect the response to PEM chemotherapy and consequently the survival outcomes in lung adenocarcinoma patients. CONCLUSION: This study suggests that genetic variants in the histone modification regions may be useful for the prediction of clinical outcomes of PEM chemotherapy in advanced lung adenocarcinoma.

Promoter-Specific Variants in NeuroD1 and H3K4me3 Coincident Regions and Clinical Outcomes of Small Cell Lung Cancer.

BACKGROUND: Neurogenic differentiation 1 (NeuroD1) is a representative small cell lung cancer (SCLC) transcription regulator involved in the carcinogenesis and behavior of SCLC. Histone modifications play an important role in transcription, and H3 lysine 4 trimethylation (H3K4me3) is primarily associated with promoter regions. METHODS: We investigated the association between single nucleotide polymorphisms (SNPs) in NeuroD1 and H3K4me3 coincident regions, selected using ChIP sequencing (ChIP-seq), and the clinical outcomes of 261 patients with SCLC. RESULTS: Among 230 SNPs, two were significantly associated with both the chemotherapy response and overall survival (OS) of patients with SCLC. RNF145 rs2043268A>G was associated with worse chemotherapy response and OS (under a recessive model, adjusted odds ratio [aOR], 0.50, 95% confidence interval [CI], 0.26-0.94, P = 0.031, and adjusted hazard ratio [aHR], 1.88, 95% CI, 1.38-2.57, P < 0.001). CINP rs762105A>G was also associated with worse chemotherapy response and OS (under a dominant model, aOR, 0.47, 95% CI, 0.23-0.99, P = 0.046, and aHR, 2.03, 95% CI, 1.47-2.82, P < 0.001). ChIP-quantitative polymerase chain reaction and luciferase assay confirmed that the two SNPs were located in the active promoter regions and influenced the promoter activity of each gene. CONCLUSION: To summarize, among SNPs selected using ChIP-seq in promoter regions with high peaks in both NeuroD1 and H3K4me3, RNF145 rs2043268A>G and CINP rs762105A>G were associated with clinical outcomes in patients with SCLC and also affected the promoter activity of each gene.

Genetic Polymorphisms in Activating Transcription Factor 3 Binding Site and the Prognosis of Early-Stage Non-Small Cell Lung Cancer.

BACKGROUND: Activating transcription factor 3 (ATF3) plays a significant role in cancer development and progression. We investigated the association between variants in expression quantitative trait loci (eQTLs) within ATF3 binding regions and the prognosis of non-small cell lung cancer (NSCLC) after surgery. METHODS: A total of 772 patients with NSCLC who underwent curative surgery were enrolled. Using a public database (http://galaxyproject.org), we selected 104 single nucleotide polymorphisms (SNPs) in eQTLs in the ATF3 binding regions. The association of those SNPs with disease-free survival (DFS) was evaluated. RESULTS: Among those SNPs, HAX1 rs11265425T>G was associated with significantly worse DFS (aHR = 1.30, 95% CI = 1.00-1.69, p = 0.05), and ME3 rs10400291C>A was associated with significantly better DFS (aHR = 0.66, 95% CI = 0.46-0.95, p = 0.03). Regarding HAX1 rs11265425T>G, the significant association remained only in adenocarcinoma, and the association was significant only in squamous cell carcinoma regarding ME3 rs10400291C>A. ChIP-qPCR assays showed that the two variants reside in active enhancers where H3K27Ac and ATF3 binding occurs. Promoter assays showed that rs11265425 G allele had significantly higher HAX1 promoter activity than T allele. HAX1 RNA expression was significantly higher in tumor than in normal lung, and higher in rs11265425 TG+GG genotypes than in TT genotype. Conversely, ME3 expression was significantly lower in tumor than in normal lung, and higher in rs10400291 AA genotype than in CC+CA genotypes. CONCLUSIONS: In conclusion, this study shows that the functional polymorphisms in ATF3 binding sites, HAX1 rs11265425T>G and ME3 rs10400291C>A are associated with the clinical outcomes of patients in surgically resected NSCLC.

Polymorphisms in Glycolysis-Related Genes Are Associated with Clinical Outcomes of Paclitaxel-Cisplatin Chemotherapy in Non-Small Cell Lung Cancer.

OBJECTIVE: This study was conducted to investigate whether polymorphisms in glycolysis-related genes are associated with clinical outcomes of patients with advanced-stage non-small cell lung cancer (NSCLC) undergoing chemotherapy. METHODS: A total of 377 patients with NSCLC were enrolled. Sixty-five single-nucleotide polymorphisms in 26 genes involved in the glycolytic pathway were evaluated. The associations of the variants with the chemotherapy response and overall survival (OS) were analyzed. RESULTS: Among the 65 variants investigated, PFKL rs2073436C>G and GPI rs7248411C>G significantly correlated with clinical outcomes after chemotherapy in multivariate analyses. PFKL rs2073436C>G was significantly associated with both a worse response to chemotherapy (adjusted odds ratio [aOR] = 0.64, 95% CI = 0.45-0.90, p = 0.01) and a worse OS (adjusted hazard ratio [aHR] = 1.35, 95% CI = 1.14-1.61, p = 0.001). GPI rs7248411C>G was significantly associated with both a better chemotherapy response (aOR = 1.58, 95% CI = 1.07-2.23, p = 0.02) and a better OS (aHR = 0.80, 95% CI = 0.66-0.98, p = 0.03). When stratified by tumor histology, PFKL rs2073436C>G was significantly associated with OS only in squamous cell carcinoma, whereas GPI rs7248411C>G exhibited a significant association with the chemotherapy response and OS only in adenocarcinoma. CONCLUSION: This result suggests that the PFKL rs2073436C>G and GPI rs7248411C>G are useful for predicting the clinical outcome of first-line paclitaxel-cisplatin chemotherapy in NSCLC.

Genetic Variants in One-Carbon Metabolism Pathway Predict Survival Outcomes of Early-Stage Non-Small Cell Lung Cancer.

BACKGROUND: This study was conducted to investigate the association between genetic variants in one-carbon metabolism and survival outcomes of surgically resected non-small cell lung cancer (NSCLC). METHODS: We genotyped 41 potentially functional variants of 19 key genes in the one-carbon metabolism pathway among 750 NSCLC patients who underwent curative surgery. The association between genetic variants and overall survival (OS)/disease-free survival (DFS) were analyzed. RESULTS: Among the 41 single-nucleotide polymorphisms (SNPs) analyzed, 4 SNPs (MTHFD1L rs6919680T>G and rs3849794T>C, MTR rs2853523C>A, and MTHFR rs4846049G>T) were significantly associated with survival outcomes. MTHFD1L rs6919680T>G and MTR rs2853523C>A were significantly associated with better OS (adjusted hazard ratio [aHR] = 0.73, 95% confidence interval [CI] = 0.54-0.99, p = 0.04) and worse OS (aHR = 2.14, 95% CI = 1.13-4.07, p = 0.02), respectively. MTHFD1L rs3849794T>C and MTHFR rs4846049G>T were significantly associated with worse DFS (aHR = 1.41, 95% CI = 1.08-1.83, p = 0.01; and aHR = 1.97, 95% CI = 1.10-3.53, p = 0.02, respectively). When the patients were divided according to histology, the associations were significant only in squamous cell carcinoma (SCC), but not in adenocarcinoma (AC). In SCC, MTHFD1L rs6919680T>G and MTR rs2853523C>A were significantly associated with better OS (aHR = 0.64, 95% CI = 0.41-1.00, p = 0.05) and worse OS (aHR = 2.77, 95% CI = 1.11-6.91, p = 0.03), respectively, and MTHFD1L rs3849794T>C and MTHFR rs4846049G>T were significantly associated with worse DFS (aHR = 1.73, 95% CI = 1.17-2.56, p = 0.01; and aHR = 2.78, 95% CI = 1.12-6.88, p = 0.03, respectively). CONCLUSIONS: Our results suggest that the genetic variants in the one-carbon metabolism pathway could be used as biomarkers for predicting the clinical outcomes of patients with early-stage NSCLC.

Genetic Variant of Notch Regulator DTX1 Predicts Survival After Lung Cancer Surgery.

BACKGROUND: We evaluated the association between genetic variants in the Notch pathway and survival outcomes of patients with surgically resected NSCLC. METHODS: Sixty-four single nucleotide polymorphisms (SNPs) in the Notch pathway genes were evaluated in the discovery study (n = 354) and two sequential validation studies (n = 772 and n = 746, respectively). The association of genotype with overall survival (OS) and disease-free survival (DFS) was evaluated. RESULTS: Of the 64 SNPs analyzed in the discovery study, 9 were significantly associated with OS or DFS. Among them, the association remained significant only for Deltex-1 (DTX1) rs1732786A>G in the first validation study. The second validation study confirmed again the association between DTX1 rs1732786A>G and survival outcomes. In the combined analysis, rs1732786A>G was significantly associated with better OS and DFS (adjusted HR ·aHR· for OS, 0.75; 95% CI 0.64-0.87; P = 0.0002; aHR for DFS, 0.79; 95% CI 0.71-0.89; P = 0.0001). In vitro luciferase assay showed that the rs1732786G allele was associated with higher promoter activity compared to rs1732786A allele. Consistently, relative mRNA expression level of DTX1 showed significant positive correlation with rs1732786 A-to-G change (Ptrend = 0.02) in tumor tissues. CONCLUSIONS: These results suggest that DTX1 rs1732786 is a potential prognostic factor that may have clinical utility in the management of early stage NSCLC.

Functional intronic variant of SLC5A10 affects DRG2 expression and survival outcomes of early-stage non-small-cell lung cancer.

RegulomeDB is a new tool that can predict the regulatory function of genetic variants. We applied RegulomeDB in selecting putative functional variants and evaluated the relationship between these variants and survival outcomes of surgically resected non-small-cell lung cancer. Among the 244 variants studied, 14 were associated with overall survival (P < 0.05) in the discovery cohort and one variant (rs2257609 C>T) was replicated in the validation cohort. In the combined analysis, rs2257609 C>T was significantly associated with worse overall and disease-free survival under a dominant model (P = 2 × 10-5 and P = 0.001, respectively). rs2257609 is located in the SLC5A10 intron, but RegulomeDB predicted that this variant affected DRG2, not SLC5A10 expression. The expression level of SLC5A10 was not different with the rs2257609 genotype. However, DRG2 expression was different according to the rs2257609 genotype (Ptrend   = 0.03) and was significantly higher in tumor than in non-malignant lung tissues (P = 1 × 10-5 ). Luciferase assay also showed higher promoter activity of DRG2 in samples with the rs2257609 T allele (P < 0.0001). rs2257609 C>T affected DRG2 expression and, thus, influenced the prognosis of early-stage non-small-cell lung cancer. This study was approved by the Institutional Review Broad of Kyungpook National University of Hospital (Approval No. KNUMC 2014-04-210-003).

Glucose Transporter 1 Gene Variants Predict the Prognosis of Patients with Early-Stage Non-small Cell Lung Cancer.

BACKGROUND: This study was conducted to investigate whether polymorphisms of glucose transporter 1 (GLUT1) gene are associated with the prognosis of patients with non-small cell lung cancer (NSCLC) after surgical resection. METHODS: Five single nucleotide polymorphisms (SNPs) in GLUT1 were investigated in a total of 354 patients with NSCLC who underwent curative surgery. The association of the SNPs with patients' survival was analyzed. RESULTS: Among the five SNPs investigated, two SNPs (GLUT1 rs3820589T > A and rs4658G > C) were significantly associated with OS in multivariate analyses. GLUT1 rs3820589T > A was associated with significantly better OS (adjusted hazard ratio [aHR] = 0.57, 95% confidence interval [CI] = 0.34-0.94, P = 0.03, under dominant model), and rs4658G > C was associated with significantly worse OS (aHR = 1.91, 95% CI = 1.09-3.33, P = 0.02, under recessive model). In the stratified analysis by tumor histology, the effect of these SNPs on OS was only significant in squamous cell carcinoma but not in adenocarcinoma. When the two SNPs were combined, OS decreased as the number of bad genotypes increased (Ptrend = 4 × 10-3). CONCLUSIONS: This study suggests that genetic variation in GLUT1 may be useful in predicting survival of patients with early stage NSCLC.

Polymorphisms in Epithelial-Mesenchymal Transition-Related Genes and the Prognosis of Surgically Treated Non-small Cell Lung Cancer.

BACKGROUND: This study was conducted to determine whether single-nucleotide polymorphisms (SNPs) in EMT-related genes may influence the prognosis of NSCLC after surgery. METHODS: There were 88 SNPs in EMT-related genes evaluated in a discovery set of 376 patients who underwent curative surgery for NSCLC. Significantly, 14 SNPs were evaluated in a validation set of 428 patients. Luciferase assay and RT-PCR were conducted to examine functional relevance of polymorphisms. RESULTS: Fourteen SNPs that were associated with survival outcomes in a discovery set were selected for validation. Among those, two SNPs (FOXF2 rs1711972A>C and HEYL rs784621G>A) were replicated in a validation study. In combined analysis, FOXF2 rs1711972 AC+CC genotype was associated with significantly better overall survival (OS) and disease-free survival (DFS) compared with AA genotype (adjusted hazard ratio [aHR] for OS = 0.67, 95% confidence interval [CI] 0.51-0.88, P = 0.004; and aHR for DFS = 0.77, 95% CI 0.62-0.95, P = 0.01). HEYL rs784621 AA genotype exhibited a significantly worse OS compared with GG+GA genotype (aHR for OS = 2.65, 95% CI 1.63-4.31, P = 8 × 10-5). FOXF2 rs1711972C allele had a significantly increased promoter activity than rs1711972A allele (P = 0.01), and HEYL rs784621A allele had a significantly lower promoter activity than rs784621G allele (P = 0.004). FOXF2 rs1711972A>C was significantly associated with increased FOXF2 mRNA expression. CONCLUSIONS: FOXF2 rs1711972A>C and HEYL rs784621G>A were associated with survival outcomes of surgically treated NSCLC. These SNPs may help to identify patients at high risk of poor disease outcomes.

Polymorphisms in cancer-related pathway genes and lung cancer.

We evaluated the associations between potentially functional variants in a comprehensive list of cancer-related genes and lung cancer in a Korean population.A total of 1969 potentially functional single nucleotide polymorphisms (SNPs) of 1151 genes involved in carcinogenesis were evaluated using an Affymetrix custom-made GeneChip in 610 nonsmall cell lung cancer patients and 610 healthy controls. A replication study was conducted in an independent set of 490 cases and 486 controls. 68 SNPs were significantly associated with lung cancer in the discovery set and tested for replication.Among the 68 SNPs, three SNPs (corepressor interacting with RBPJ 1 (CIR1) rs13009079T>C, ribonucleotide reductase M1 (RRM1) rs1465952T>C and solute carrier family 38, member 4 (SLC38A4) rs2429467C>T) consistantly showed significant associations with lung cancer in the replication study. In combined analysis, adjusted odds ratio for CIR1 rs13009079T>C, RRM1 rs1465952T>C and SLC38A4 rs2429467C>T were 0.69, 0.71 and 0.73, respectively (p=4×10-5, 0.01 and 0.001, respectively) under the dominant model. The relative mRNA expression level of CIR1 was significantly associated with rs13009079T>C genotypes in normal lung tissues (ptrend=0.03).These results suggest that the three SNPs, particularly CIR1 rs13009079T>C, may play a role in the pathogenesis of lung cancer.

Genetic Variants in the Wnt Signaling Pathway Are Not Associated with Survival Outcome of Non-Small Cell Lung Cancer in a Korean Population.

Recently, genetic variants in the WNT signaling pathway have been reported to affect the survival outcome of Caucasian patients with early stage non-small cell lung cancer (NSCLC). We therefore attempted to determine whether these same WNT signaling pathway gene variants had similar impacts on the survival outcome of NSCLC patients in a Korean population. A total of 761 patients with stages I-IIIA NSCLC were enrolled in this study. Eight variants of WNT pathway genes were genotyped and their association with overall survival and disease-free survival were analyzed. None of the eight variants were significantly associated with overall survival or disease-free survival. There were no differences in survival outcome after stratifying the subjects according to age, gender, smoking status, and histological type. These results suggest that genetic variants in the WNT signaling pathway may not affect the survival outcome of NSCLC in a Korean population.

The Different Effect of VEGF Polymorphisms on the Prognosis of Non-Small Cell Lung Cancer according to Tumor Histology.

Vascular endothelial growth factor (VEGF) contributes to tumor angiogenesis. The role of VEGF single nucleotide polymorphisms (SNPs) in lung cancer susceptibility and its prognosis remains inconclusive and controversial. This study was performed to investigate whether VEGF polymorphisms affect survival outcomes of patients with early stage non-small cell lung cancer (NSCLC) after surgery. Three potentially functional VEGF SNPs (rs833061T>C, rs2010963G>C, and rs3025039C>T) were genotyped. A total of 782 NSCLC patients who were treated with surgical resection were enrolled. The association of the SNPs with overall survival (OS) and disease free survival (DFS) was analyzed. In overall population, none of the three polymorphisms were significantly associated with OS or DFS. However, when the patients were stratified by tumor histology, squamous cell carcinoma (SCC) and adenocarcinoma (AC) had significantly different OS (Adjusted hazard ratio [aHR] = 0.76, 95% CI = 0.56-1.03 in SCC; aHR = 1.33, 95% CI = 0.98-1.82 in AC; P for heterogeneity = 0.01) and DFS (aHR = 0.75, 95% CI = 0.58-0.97 in SCC; aHR = 1.26, 95% CI = 1.00-1.60 in AC; P for heterogeneity = 0.004) according to the rs833061T>C genotypes. Our results suggest that the prognostic role of VEGF rs833061T>C may differ depending on tumor histology.

TERT Polymorphism rs2853669 Influences on Lung Cancer Risk in the Korean Population.

Short telomeres are known as one of the risk factors for human cancers. The present study was conducted to evaluate the association between 6 polymorphisms, which were related with short telomere length in the Korean population, and lung cancer risk using 1,100 cases and 1,096 controls. Among the 6 polymorphisms, TERT rs2853669 was significantly associated with increased lung cancer risk under a recessive model (odds ratio [OR]=1.38, 95% confidence interval [CI]=1.05-1.81, P=0.02). The effect of rs2853669 on lung cancer risk was significant in younger individuals (OR=1.73, 95% CI=1.18-2.54, P=0.005) and adenocarcinoma (OR=1.50, 95% CI=1.07-2.07, P=0.02). Our results suggest that a common functional promoter polymorphism, TERT rs2853669, may influence both telomere length and lung cancer risk in the Korean population.

Telomere length of tumor tissues and survival in patients with early stage non-small cell lung cancer.

Telomere shortening leads to genomic instability that drives oncogenesis through the activation of telomerase and the generation of other mutations necessary for tumor progression. This study was conducted to determine the impact of telomere shortening on the survival of patients with early stage non-small cell lung cancer (NSCLC). Relative telomere length in tumor tissues was measured by quantitative polymerase chain reaction in 164 patients with surgically resected NSCLC. The association between telomere length and overall survival (OS) and disease-free survival (DFS) was analyzed. When the patients were categorized into quartiles based on telomere length, those patients with the 1st quartile (shortest) of telomere length had a significantly worse OS and DFS compared to patients with the 2nd to the 4th quartiles of telomere length (adjusted hazard ratio for OS = 2.67, 95% confidence interval = 1.50-4.75, P = 0.001; and adjusted hazard ratio for DFS = 1.92, 95% confidence interval = 1.17-3.14, P = 0.01). An association between telomere length and survival outcome was more pronounced in squamous cell carcinomas than adenocarcinomas (P-value of test for homogeneity for OS and DFS = 0.05 and 0.02, respectively). Telomere length of tumor tissues is an independent prognostic factor in patients with surgically resected early stage NSCLC.

RET fusion genes in Korean non-small cell lung cancer.

Recently, rearranged during transfection (RET) fusions have been identified in approximately 1% of non-small cell lung cancer (NSCLC). To know the prevalence of RET fusion genes in Korean NSCLCs, we examined the RET fusion genes in 156 surgically resected NSCLCs using a reverse transcriptase polymerase chain reaction. Two KIF5B-RET fusions and one CCDC6-RET fusion were identified. All three patients were females and never smokers with adenocarcinomas. RET fusion genes were mutually exclusive from EGFR, KRAS mutations and EML4-ALK fusion. RET fusion genes occur 1.9% (3 of 156) of surgically treated NSCLC patients in Koreans.

Genome-wide association study of lung cancer in Korean non-smoking women.

Lung cancer in never-smokers ranks as the seventh most common cause of cancer death worldwide, and the incidence of lung cancer in non-smoking Korean women appears to be steadily increasing. To identify the effect of genetic polymorphisms on lung cancer risk in non-smoking Korean women, we conducted a genome-wide association study of Korean female non-smokers with lung cancer. We analyzed 440,794 genotype data of 285 cases and 1,455 controls, and nineteen SNPs were associated with lung cancer development (P < 0.001). For external validation, nineteen SNPs were replicated in another sample set composed of 293 cases and 495 controls, and only rs10187911 on 2p16.3 was significantly associated with lung cancer development (dominant model, OR of TG or GG, 1.58, P = 0.025). We confirmed this SNP again in another replication set composed of 546 cases and 744 controls (recessive model, OR of GG, 1.32, P = 0.027). OR and P value in combined set were 1.37 and < 0.001 in additive model, 1.51 and < 0.001 in dominant model, and 1.54 and < 0.001 in recessive model. The effect of this SNP was found to be consistent only in adenocarcinoma patients (1.36 and < 0.001 in additive model, 1.49 and < 0.001 in dominant model, and 1.54 and < 0.001 in recessive model). Furthermore, after imputation with HapMap data, we found regional significance near rs10187911, and five SNPs showed P value less than that of rs10187911 (rs12478012, rs4377361, rs13005521, rs12475464, and rs7564130). Therefore, we concluded that a region on chromosome 2 is significantly associated with lung cancer risk in Korean non-smoking women.

Epigenetic and genetic inactivation of tumor suppressor miR-135a in non-small-cell lung cancer.

BACKGROUND: Despite therapeutic advances, lung cancer prognosis remains poor. Loss of heterozygosity (LOH) in the 3p21 region is well documented in lung cancer, but the specific causative genes have not been identified. MATERIALS AND METHODS: Here, we aimed to examine the clinical impact of miR-135a, located in the 3p21 region, in lung cancer. miR-135a expression was assessed using quantitative real-time polymerase chain reaction. LOH was analyzed at microsatellite loci D3S1076 and D3S1478, and promoter methylation status was determined by pyrosequencing of resected samples of primary non-small-cell lung cancer (NSCLC). The regulation of telomerase reverse transcriptase (TERT) was evaluated in lung cancer cells H1299 by luciferase report assays after treatment with miR-135a mimics. RESULTS: miR-135a was significantly downregulated in squamous cell cancer (SCC) tumor tissues compared to normal tissues (p = 0.001). Low miR-135a expression was more frequent in patients with SCC (p = 2.9 × 10-4 ) and smokers (p = 0.01). LOH and hypermethylation were detected in 27.8% (37/133) and 17.3% (23/133) of the tumors, respectively. Overall, 36.8% (49/133) of the NSCLC cases harbored either miR-135a LOH or promoter hypermethylation. The frequencies of LOH and hypermethylation were significantly associated with SCCs (p = 2 × 10-4 ) and late-stage (p = 0.04), respectively. MiR-135a inhibited the relative luciferase activity of psiCHECK2-TERT-3'UTR. CONCLUSION: These results suggest that miR-135a may act as a tumor suppressor to play an important role in lung cancer carcinogenesis, which will provide a new insight into the translational value of miR-135a. Further large-scale studies are required to confirm these findings.

Genetic variants of NEUROD1 target genes are associated with clinical outcomes of small-cell lung cancer patients.

BACKGROUND: Neurogenic differentiation factor 1 (NEUROD1) is frequently overexpressed in small-cell lung cancer (SCLC). NEUROD1 plays an important role in promoting malignant behavior and survival. METHODS: In this study, we evaluated the association between putative functional polymorphisms in 45 NEUROD1 target genes and chemotherapy response and survival outcomes in 261 patients with SCLC. Among the 100 single nucleotide polymorphisms (SNPs) studied, two were significantly associated with both chemotherapy response and overall survival (OS) of patients with SCLC. RESULTS: The SNP rs3806915C>A in semaphorin 6A (SEMA6A) gene was significantly associated with better chemotherapy response and OS (p = 0.04 and p = 0.04, respectively). The SNP rs11265375C>T in nescient helix-loop helix 1 (NHLH1) gene was also associated with better chemotherapy response and OS (p = 0.04 and p = 0.02, respectively). Luciferase assay showed a significantly higher promoter activity of SEMA6A with the rs3806915 A allele than C allele in H446 lung cancer cells (p = 4 × 10-6 ). The promoter activity of NHLH1 showed a significantly higher with the rs11265375 T allele than C allele (p = 0.001). CONCLUSION: These results suggest that SEMA6A rs3806915C>A and NHLH1 rs11265375C>T polymorphisms affect the promoter activity and expression of the genes, which may affect the survival outcome of patients with SCLC.

Genetic variants in key necroptosis regulators predict prognosis of non-small cell lung cancer after surgical resection.

BACKGROUND: Necroptosis is a regulated inflammatory cell death which plays a significant role in cancer development and progression. In this study, we evaluated whether genetic variants in key regulators of necroptosis may affect survival outcome of non-small cell lung cancer (NSCLC) patients after surgical resection. METHODS: A total of 674 patients who underwent curative surgery were included. Fifteen genetic variants in key regulators of necroptosis (RIPK1, RIPK3, and MLKL) were selected. The association of these variants with survival outcomes was evaluated. RESULTS: Two variants, RIPK1 rs17548629C > T and MLKL rs877375G > C, were associated with better overall survival and disease-free survival in multivariate analyses. When the patients were divided according to histology, the associations were significant only in adenocarcinoma, but not in squamous cell carcinoma. RIPK1 rs17548629 C-to-T change was associated with significantly increased luciferase activity by modulating the binding of miR-642a. Promoter assays showed a significantly increased promoter activity in MLKL rs877375C allele compared to G allele. Consistently, the mRNA expression level of RIPK1 and MLKL showed significant positive correlation with RIPK1 rs17548629C-to-T and MLKL rs877375G-to-C changes. CONCLUSION: Two genetic variants in key regulators in necroptosis, RIPK1 rs17548629C > T and MLKL rs877375G > C, may be used as biomarkers to predict survival outcomes in surgically resected NSCLC patients.