Seung Soo Yoo

Somatic mutations in epidermal growth factor receptor signaling pathway genes in non-small cell lung cancers.

Introduction: Epidermal growth factor receptor (EGFR) signaling pathway plays a crucial role in the development and progression of lung cancer. We searched for mutations of EGFR pathway genes in non-small cell lung cancers (NSCLCs) and analyzed their relationship with clinicopathologic features. Methods: Mutations of EGFR, ERBB2, ERBB3, ERBB4, KRAS, NRAS, BRAF, PTEN, PIK3CA, LKB1, and AKT1 genes were determined by direct sequencing in 173 surgically resected NSCLCs—56 squamous cell carcinomas (SCCs) and 117 adenocarcinomas (ACs). Results: Of the 173 NSCLCs, a total of 65 mutations were detected in 63 (36.4%) tumors—10 (17.9%) in SCCs and 53 (45.3%) in ACs. Mutations in EGFR pathway genes were significantly more frequent in women and ACs than in women and SCCs (p = 0.02 and p < 0.001, respectively). The mutations occurred in a mutually exclusive pattern. When the genes were divided into three subgroups according to their roles in the signaling cascade, mutations in the EGFR/ERBB2 and KRAS/BRAF genes were more frequent in ACs than in SCCs (p < 0.001 and p = 0.01, respectively). In marked contrast, mutations in the PIK3CA/PTEN were more frequent in SCCs than in ACs (p = 0.002). Furthermore, mutations in the PIK3CA/PTEN genes were more frequent in smokers (p = 0.04). Discussion: Our study demonstrates that mutations in each part of the EGFR pathway were associated with different clinicopathologic features in patients with NSCLCs.

Polymorphisms in the CASPASE Genes and Survival in Patients With Early-Stage Non–Small-Cell Lung Cancer

PURPOSE This study was conducted to determine the impact of potentially functional polymorphisms in the CASPASE (CASP) genes on the survival of early-stage non-small-cell lung cancer (NSCLC) patients. PATIENTS AND METHODS Four hundred eleven consecutive patients with surgically resected NSCLC were enrolled. Nine potentially functional polymorphisms in the CASP3, CASP7, CASP8, CASP9, and CASP10 genes were investigated. The genotype and haplotype associations with overall survival (OS) and disease-free survival (DFS) were analyzed. RESULTS Patients with the rs2227310 GG genotype had a significantly decreased OS and DFS compared with patients with the CC + CG genotype (adjusted hazard ratio [aHR] for OS, 1.67; 95% CI, 1.19 to 2.35; P = .003; aHR for DFS, 1.62; 95% CI, 1.19 to 2.22; P = .002). The rs4645981C>T genotype also had a significant effect on OS and DFS (under a recessive model; aHR for OS, 2.00; 95% CI, 1.04 to 3.85; P = .04; aHR for DFS, 2.76; 95% CI, 1.58 to 4.80; P = .0003). When the rs2227310 and rs4645981 genotypes were combined, patients with one or two bad genotypes had worse OS and DFS compared with those who had zero bad genotypes (aHR for OS, 1.75; 95% CI, 1.25 to 2.45; P = .001; aHR for DFS, 1.66; 95% CI, 1.23 to 2.26; P = .001). CONCLUSION The CASP7 rs2227310 and CASP9 rs4645981 polymorphisms may affect survival in early-stage NSCLC. The analysis of these polymorphisms can help identify patients at high risk for a poor disease outcome.

A common polymorphism in pre-microRNA-146a is associated with lung cancer risk in a Korean population

INTRODUCTION MicroRNAs (miRs) play important roles in the development and progression of human cancers. MiR-146a down-regulates epidermal growth factor receptor and the nuclear factor-κB regulatory kinase interleukin-1 receptor-associated kinase 1 genes that play important roles in lung carcinogenesis. This study was conducted to evaluate the association between rs2910164C>G, a functional polymorphism in the pre-miR-146a, and lung cancer risk. MATERIAL AND METHODS The rs2910164C>G genotypes were determined in 1094 patients with lung cancer and 1100 healthy controls who were frequency matched for age and gender. RESULTS The rs2910164 CG or GG genotype was associated with a significantly decreased risk for lung cancer compared to that of the CC genotype (adjusted odds ratio=0.80, 95% confidence interval=0.66-0.96, P=0.02). When subjects were stratified according to smoking exposure (never, light and heavy smokers), the effect of the rs2910164C>G genotype on lung cancer risk was significant only in never smokers (adjusted odds ratio=0.66, 95% confidence interval=0.45-0.96, P=0.03, under a dominant model for the C allele) and decreased as smoking exposure level increased (Ptrend<0.001). In line with this result, the level of miR-146a expression in the tumor tissues was significantly higher in the GG genotype than in the CC or CG genotype only in never-smokers (P=0.02). CONCLUSIONS These findings suggest that the rs2910164C>G in pre-miR-146a may contribute to genetic susceptibility to lung cancer, and that miR-146a might be involved in lung cancer development.

Polymorphisms in DNA repair and apoptosis-related genes and clinical outcomes of patients with non-small cell lung cancer treated with first-line paclitaxel-cisplatin chemotherapy

This study was conducted to analyze a comprehensive panel of single nucleotide polymorphisms (SNPs) in genes in DNA repair and apoptosis pathways and determine the relationship between polymorphisms and treatment outcomes of patients with non-small cell lung cancer (NSCLC) treated with first-line paclitaxel-cisplatin chemotherapy. Three hundred eighty two patients with NSCLC were enrolled. Seventy-four SNPs in 48 genes (42 SNPs in 27 DNA repair pathway genes and 32 SNPs in 21 apoptotic pathway genes) were genotyped and their associations with chemotherapy response and overall survival (OS) were analyzed. Among SNPs in DNA repair genes, BRCA1 rs799917 was significantly associated with both chemotherapy response and OS. XRCC1 rs25487 exhibited a significant association with chemotherapy response and ERCC2 rs1052555 with OS. Four SNPs in apoptotic genes (TNFRSF1B rs1061624, BCL2 rs2279115, BIRC5 rs9904341, and CASP8 rs3769818) were significantly associated with OS, but not with response to chemotherapy. When the six SNPs which were associated with OS in individual analysis were combined, OS decreased as the number of bad genotypes increased (P(trend) = 2 × 10(-6)). Patients with 3, and 4-6 bad genotypes had significantly worse OS compared with those carrying 0-2 bad genotypes (adjusted hazard ratio [aHR] = 1.54, 95% CI = 1.14-2.08, P = 0.005; aHR = 2.10, 95% CI = 1.55-2.85, P = 2 × 10(-6), respectively). In conclusion, these findings suggest that the six SNPs identified, particularly their combined genotypes, could be used as biomarkers predicting chemotherapy response and survival of NSCLC patients treated with first-line paclitaxel-cisplatin chemotherapy.

PD-L1 polymorphism can predict clinical outcomes of non-small cell lung cancer patients treated with first-line paclitaxel-cisplatin chemotherapy

This study was conducted to investigate whether polymorphisms of genes involved in immune checkpoints can predict the clinical outcomes of patients with advanced stage non-small cell lung cancer (NSCLC) after 1st line paclitaxel-cisplatin chemotherapy. A total of 379 NSCLC patients were enrolled. Twelve single nucleotide polymorphisms (SNPs) of PD-1, PD-L1, and CTLA-4 genes were selected and genotyped. The associations of SNPs with chemotherapy response and overall survival (OS) were analyzed. Among the 12 SNPs investigated, PD-L1 rs2297136T > C and rs4143815C > G were significantly associated with clinical outcomes after chemotherapy. The rs2297136T > C was significantly associated with both better chemotherapy response and better OS, and the rs4143815C > G had a significantly better response to chemotherapy. Consistent with the individual genotype analyses, rs2297136C-rs4143815G haplotype (ht4) carrying variant alleles at both loci was significantly associated with better chemotherapy response and OS compared with combined other haplotypes. Patients with at least one ht4 had significantly better chemotherapy response and OS compared to those without ht4. PD-L1 rs2297136T > C and rs4143815C > G polymorphisms may be useful for the prediction of clinical outcome of 1st line paclitaxel-cisplatin chemotherapy in NSCLC. Further studies are needed to confirm our findings and to understand the role of PD-L1 in the chemotherapy outcome of NSCLC patients.

Putative functional variants of XRCC1 identified by RegulomeDB were not associated with lung cancer risk in a Korean population

The Encyclopedia of DNA elements (ENCODE) project revealed that nearby or distantly located non-coding DNA regulates the expression of coding genes. RegulomeDB (http://regulome.stanford.edu) is a new database that can be used to predict whether a variant affects transcription factor binding and gene expression. We investigated the association between lung cancer risk and potentially functional polymorphisms of XRCC1 that were selected using RegulomeDB in a Korean population. A total of 185 polymorphisms of XRCC1 were evaluated using RegulomeDB. Strong evidence suggested that 10 polymorphisms, from among the 185, affected XRCC1 expression with scores of 1a-1f that were based on the RegulomeDB scoring system. The rs2854510 polymorphism was rare in Asians (minor allele frequency < 0.05). Eight polymorphisms were in strong linkage disequilibrium (LD). The rs2854509 polymorphism, which was one of the 8 polymorphisms in LD, and rs7248167, which was not in the LD block, were genotyped in 610 lung cancer patients and 607 age- and sex-matched controls. Additionally, four polymorphisms of XRCC1 (rs25487, rs25489, rs1799782, and rs3213245), which were investigated with regard to their association with lung cancer risk in previous studies, were also genotyped. Two polymorphisms (rs2854509 and rs7248167) that were predicted to affect XRCC1 expression based on their RegulomeDB scores were not associated with lung cancer risk (P = 0.31 and 0.93, respectively). When stratified according to age, gender, smoking status, and tumor histology, the two polymorphisms of XRCC1 were not associated with lung cancer risk. Among the four polymorphisms that were previously studied, only rs25489 of XRCC1 was significantly associated with lung cancer risk (dominant model, adjusted odds ratio = 0.61, 95% confidence interval = 0.46-0.83, P = 0.002). Although RegulomeDB is an attractive tool for predicting the regulatory potential of variants, the two polymorphisms that were selected using RegulomeDB were not associated with lung cancer risk.

Association between Genetic Variants in Pre-MicroRNAs and Survival of Early-Stage NSCLC

Introduction: MicroRNAs (miRNAs) are an abundant class of small non–protein-coding RNAs that function as negative gene regulators. Recent evidence indicates that altered miRNA expression plays an important role in the initiation and progression of lung cancer. Single nucleotide polymorphisms (SNPs) in pre-miRNAs could alter miRNAs processing, or expression, and hence, could influence the prognosis of lung cancer. To test this hypothesis, we evaluated the effects of four SNPs in pre-miRNAs (pre-miR-146a rs2910164, pre-miR-149 rs2292832, pre-miR-196a rs11614913, and pre-miR-499 rs3746444) on the survival outcomes of patients with early-stage non–small-cell lung cancer (NSCLC). Methods: Three hundred sixty-three patients with surgically resected NSCLC were enrolled. The four SNPs were genotyped using a polymerase chain reaction-restriction fragment length polymorphism assay. The genotype associations with overall survival (OS) and disease-free survival (DFS) were analyzed. Results: Of the four SNPs examined, the pre-miR-149 rs2292832T>C and pre-miR-196a rs11614913C>T were found to be significantly associated with OS and DFS. The rs2292832 TC or CC genotype exhibited a significantly better OS and DFS compared with the rs2292832 TT genotype (adjusted hazard ratio [aHR] for OS, 0.66; 95% confidence interval [CI], 0.47–0.92; p = 0.01 and aHR for DFS, 0.64; 95% CI, 0.48–0.87; p = 0.004). For the pre-miR-196a rs11614913C>T, patients with the CT or TT genotype had a significantly better OS and DFS than those with the CC genotype (aHR for OS, 0.70; 95% CI, 0.49–0.99; p = 0.05 and aHR for DFS, 0.66; 95% CI, 0.48–0.90; p = 0.01). When the two SNPs were combined, OS and DFS improved in a dose-dependent manner as the number of good genotypes increased (p = 0.002 and 0.0001, respectively). Conclusions: These results suggest that miR-149 and miR-196a may be involved in the pathogenesis of NSCLC, and that rs2292832 and rs11614913 can be used as prognostic markers for patients with surgically resected early-stage NSCLC.

Comparative analysis of whole‐blood interferon‐γ and flow cytometry assays for detecting post‐treatment immune responses in patients with active tuberculosis

Background: Intracellular cytokine flow cytometry (ICCFC) has been explored to detect tuberculosis (TB) infections; however, there are little data regarding its use to examine the dynamic responses of Mycobacterium tuberculosis (MTB)-specific T-cells after anti-tuberculous therapy. The aim of the present study was to analyze both dynamic changes in functional MTB antigen-specific T-cell subsets and interferon-gamma (IFN-γ) levels using ICCFC and the QuantiFERON-TB Gold In-Tube (QFT-IT) test, respectively, following anti-tuberculous treatment in patients with active TB. Methods: Twenty-six patients with active TB were enrolled in the study, and QFT-IT and ICCFC were performed simultaneously both before and after treatment. IFN-γ levels (QFT-IT test) and the numbers of IFN-γ- or tumor necrosis factor-alpha (TNF-α)-expressing T-cells (ICCFC assay) were examined after stimulation with MTB antigen. Results: There was no significant reduction in the mean IFN-γ concentrations measured by the QFT-IT test after anti-tuberculous treatment (p=0.314). ICCFC analysis showed that the numbers of IFN-γ+ /CD4- T-cells and CD4+ T-cells producing TNF-α, either alone or in combination with IFN-γ, were significantly reduced after anti-tuberculous treatment. The IFN-γ+ /TNF-α+ /CD4+ T-cell subset showed the greatest difference between untreated and treated patients with active TB (area under the curve = 0.734, p=0.004). Conclusions: Unlike the QFT-IT test, ICCFC provides diverse immunological information about dynamic changes in the number of MTB antigen-specific T-cells following anti-tuberculous therapy. Thus, analysis of MTB antigen-stimulated T-cell responses using ICCFC might have a role to play in monitoring treatment responses in patients with active TB.

EML4-ALK Fusion Gene in Korean Non-Small Cell Lung Cancer

A fusion gene between echinoderm microtubule-associated protein-like 4 (EML4) and the anaplastic lymphoma kinase (ALK) has been identified in non-small cell lung cancers (NSCLCs). Although a few studies have evaluated EML4-ALK fusion genes in Korean NSCLCs, the prevalence of different EML4-ALK fusion variants has yet to be clearly assessed. Herein, we have examined the profiles of EML4-ALK fusion gene variants in Korean patients of NSCLCs. EML4-ALK fusion genes have been detected in 10 (6.0%) of 167 patients of NSCLCs and in 9 (7.4%) of 121 patients of adenocarcinoma. Of the 10 patients with fusion genes identified, 8 (80%) were E13;A20 (variant 1) and 2 (20%) were E6;A20, with an additional 33-bp sequence derived from intron 6 of EML4 (variant 3b). These results indicate that the profiles of EML4-ALK fusion gene variants in Korean patients of NSCLC may differ from those in other ethnic populations. Herein, we describe for the first time the profiles of EML4-ALK fusion variants of Korean patients with NSCLCs.

A Functional Polymorphism in CSF1R Gene Is a Novel Susceptibility Marker for Lung Cancer among Never-Smoking Females

Introduction: It has been estimated that the proportion of never-smokers among females with lung cancer is 53% worldwide and 75% in Korea. We conducted a two-stage study to identify genetic factors responsible for lung cancer susceptibility in female never-smokers. Materials and Methods: In a discovery set, 1969 potentially functional single nucleotide polymorphisms (SNPs) of 1151 genes, which were related to cancer development and progression, were evaluated using the Affymetrix custom-made GeneChip in 181 female never-smokers with lung cancer and 179 controls. A replication study was performed on an independent cohort of 596 cases and 1194 healthy controls. Results: Sixteen SNPs with p < 0.05 for genotype distribution in the discovery set were enrolled in the replication study. Among 16 SNPs, three SNPs (colony-stimulating factor 1 receptor [CSF1R] rs10079250A>G, tumor protein p63 [TP63] rs7631358G>A, and corepressor interacting with RBPJ 1 [CIR1] rs13009079T>C) were found to be significantly associated with lung cancer in the same direction as the discovery set. Homology-based model for CSF1R indicated that the rs10079250A>G leads to increased positive charge of CSF-binding region of CSF1R, thereby increasing the chance of binding between CSF and CSF1R. In addition, this SNP was found to increase the phosphorylation of a mitogen-activated protein kinase, JNK. Conclusions: Our results suggest that the three SNPs, particularly CSF1R rs10079250, may contribute to lung cancer susceptibility in never-smoking females.