Guang Jin

PTEN mutations and relationship to EGFR, ERBB2, KRAS, and TP53 mutations in non-small cell lung cancers.

Somatic mutations of phosphatase and tensin homolog deleted on chromosome ten (PTEN) in non-small cell lung cancers (NSCLCs) have been investigated in but a small number of cases. In addition, the relationship between PTEN mutations and epidermal growth factor receptor (EGFR), KRAS, and TP53 mutations has not been investigated. Therefore, we investigated the frequency of PTEN mutations in 176 surgically resected NSCLCs and analyzed the relationship between PTEN mutations and EGFR, ERBB2, KRAS, and TP53 mutations. Mutations of PTEN (exons 1-9), EGFR (exons 18-21), ERBB2 (exons 19 and 20), KRAS (exon 1), and TP53 (exons 2-11) were determined by polymerase chain reaction and direct sequencing. PTEN mutations were present in 8 (4.5%) of the 176 tumors. PTEN mutations were only found in ever-smokers and were significantly more frequent in squamous cell carcinoma than in adenocarcinoma (10.2% vs 1.7%, P=0.02). Mutations of EGFR, ERBB2, KRAS, and TP53 genes were found in 36 (20.5%), 2 (1.1%), 11 (6.3%), and 66 (37.5%) cases, respectively. Of the 8 tumors with PTEN mutations, 1 case concurrently had an EGFR mutation and 4 cases had TP53 mutations. However, PTEN mutations were not found in the tumors with KRAS mutation. Our findings indicate that PTEN mutations are relatively common in NSCLC, and thus analysis of PTEN mutations may facilitate a comprehensive understanding of the genetic alterations related to the EGFR signaling pathway.

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.

Association of a common AGO1 variant with lung cancer risk: a two-stage case-control study.

Based on the important role of microRNA (miRNA) biosynthesis genes in carcinogenesis, we hypothesized that polymorphisms in the miRNA biosynthesis genes may modulate susceptibility to lung cancer. To test this hypothesis, we conducted a two‐stage study to evaluate the associations between single nucleotide polymorphisms (SNPs) in the miRNA biosynthesis genes and the risk of lung cancer. In stage 1 of the study, 24 SNPs in the 11 miRNA biosynthesis genes (DROSHA, DGCR8, RAN, XPO5, DICER, AGO1, AGO2, HIWI, GEMIN3, GEMIN4, and TRBP) were genotyped in 100 lung cancer patients and 100 healthy controls using a sequenome mass spectrometry‐based genotyping assay. One promising SNP (AGO1 rs636832A > G) was selected for stage 2 of the study, and genotyped by a melting‐curve analysis using fluorescence‐labeled hybridization probes in an independent set of 552 cases and 552 controls. The AGO1 rs636832A > G exhibited highly consistent results between the two stages of the study. In combined analysis, the 636832A > G was associated with a significantly decreased risk of lung cancer in a dose‐dependent manner (Ptrend = 6.0 × 10−4). Individuals with at least one rs636832G allele were at a significantly decreased risk of lung cancer compared with those with the AA genotype (adjusted odds ratio = 0.67, 95% confidence interval = 0.53–0.84, P = 4.0 × 10−4). This finding suggests that the AGO1 rs636832A > G might be a useful marker for determining the susceptibility to lung cancer and that the AGO1 gene might be involved in the development of lung cancer.

Polymorphisms in the caspase genes and the risk of lung cancer.

Introduction: Caspases (CASPs) are important regulators and executioners in apoptosis pathway and play a crucial role in the development and progression of cancer. On the basis of the interactions of CASPs in the apoptotic pathway, we evaluated the association between 11 polymorphisms of CASP3, 6, 7, 8, 9, and 10 genes and the risk of lung cancer. Methods: The genotypes were determined in 720 patients with lung cancer and 720 healthy controls frequency matched for age and gender. Results: In individual polymorphism analysis, the CASP7 rs2227310C>G and CASP9 rs4645981C>T were associated with 1.40-fold and 1.28-fold increased risk of lung cancer under recessive and dominant models for the variant allele of each polymorphism, respectively. In the case of the CASP3 77G>A, subjects with the GG genotype were at a 1.19-fold increased risk of lung cancer compared with those with at least one variant allele. When the three polymorphisms were combined, the risk of lung cancer increased in a dose-dependent manner as the number of risk genotypes increased (ptrend <0.001). Subjects with two and three risk genotypes carried a significantly increased risk of lung cancer compared with those with zero risk genotype (adjusted odds ratio = 1.56, 95% confidence interval = 1.14–2.13, p = 0.005 and adjusted odds ratio = 2.54, 95% confidence interval = 1.28–5.02, p = 0.008, respectively). Conclusions: These results suggest that a combined analysis of these three CASP gene polymorphisms might better predict the risk of lung cancer than analysis of a single polymorphism.

Dual roles of a variable number of tandem repeat polymorphism in the TERT gene in lung cancer

This study was conducted to determine the impact of a functional tandem repeat minisatellite (MNS16A) polymorphism in the telomerase reverse transcriptase (TERT) gene on the risk of lung cancer, as well as on survival of patients with non‐small‐cell lung cancer (NSCLC). The effect of the MNS16A variable number of tandem repeat (VNTR) polymorphism on the risk of lung cancer was evaluated in a case–control study that consisted of 937 lung cancer patients and 943 healthy controls. The effect of the polymorphism on survival outcome was evaluated in 703 patients with surgically resected NSCLC. Compared with the VNTR‐302 allele, the VNTR‐243 allele was associated with a significantly increased risk of lung cancer (adjusted odds ratio, 1.55; 95% confidence interval [CI], 1.07–2.25; P = 0.02). In addition, the genotypes carrying at least one VNTR‐243 allele were associated with a significantly increased risk of lung cancer compared with the genotypes with no VNTR‐243 allele (adjusted odds ratio, 1.61; 95% CI, 1.09–2.38; P = 0.02). In contrast to the effect of the polymorphism on the risk of lung cancer, the genotypes carrying at least one VNTR‐243 allele were associated with a significantly better overall survival in patients with surgically resected NSCLC (adjusted hazard ratio, 0.51; 95% CI, 0.28–0.93; P = 0.03). These findings suggest that the MNS16A VNTR polymorphism in the TERT gene has dual, conflicting roles in lung carcinogenesis. This polymorphism may increase the risk of lung cancer development, and may improve survival in lung cancer patients. (Cancer Sci 2011; 102: 144–149)

TP53 Mutations in Korean Patients with Non-small Cell Lung Cancer

Although TP53 mutations have been widely studied in lung cancer, the majority of studies have focused on exons 5-8 of the gene. In addition, TP53 mutations in Korean patients with lung cancers have not been investigated. We searched for mutations in the entire coding exons, including splice sites of the gene, in Korean patients with non-small cell lung cancer (NSCLC). Mutations of the gene were determined by direct sequencing in 176 NSCLCs. Sixty-nine mutations (62 different mutations) were identified in 65 tumors. Of the 62 mutations, 12 were novel mutations. TP53 mutations were more frequent in males, ever-smokers and squamous cell carcinomas than in females, never-smokers and adenocarcinomas, respectively (all comparisons, P<0.001). Missense mutations were most common (52.2%), but frameshift, nonsense, and splice-site mutations were frequently observed at frequencies of 18.8%, 15.9% and 10.1%, respectively. Of the 69 mutations, 9 (13.0%) were found in the oligomerization domain. In addition, the proportion of mutations in the oligomerization domain was significantly higher in adenocarcinomas than in squamous cell carcinomas (23.5% vs. 2.9%, P=0.01). Our study provides clinical and molecular characteristics of TP53 mutations in Korean patients with NSCLCs.

Comprehensive analysis of DNA repair gene polymorphisms and survival in patients with early stage non-small-cell lung cancer.

This study was conducted to analyze a comprehensive panel of single nucleotide polymorphisms (SNP) in DNA repair genes to determine the relationship between polymorphisms and the survival outcome of patients with early stage non‐small‐cell lung cancer (NSCLC). Three hundred and ten consecutive patients with surgically resected NSCLC were enrolled. Forty‐eight SNP in 27 DNA repair genes were genotyped and their associations with overall survival (OS) and disease‐free survival (DFS) were analyzed. Individually, six SNP exhibited significant associations with survival outcome. When the six SNP were combined, OS and DFS decreased as the number of bad genotypes increased (Ptrend < 0.0001 for both). Patients with three, and four or five bad genotypes had a significantly worse OS and DFS compared with those carrying zero or one bad genotypes (adjusted hazard ratio [aHR] for OS = 3.53, 95% confidence interval [CI] = 1.25–9.97, P = 0.02, and aHR for DFS = 3.31, 95% CI = 1.41–7.76, P = 0.006; and aHR for OS = 5.47, 95% CI = 1.87–16.00, P = 0.002, and aHR for DFS = 4.42, 95% CI = 1.82–10.74, P = 0.001, respectively). These findings suggest that the six SNP identified can be used as prognostic markers for patients with surgically resected early stage NSCLC. (Cancer Sci 2010; 101: 2436–2442)

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.

Associations between polymorphisms in DNA repair genes and TP53 mutations in non-small cell lung cancer

This study was conducted to identify genetic factors predisposing to TP53 mutations in patients with non-small cell lung cancer (NSCLC). A comprehensive panel of potentially functional single nucleotide polymorphisms (SNPs) in DNA repair genes was evaluated in relation to TP53 mutations. Thirty-seven SNPs in 28 DNA repair genes were genotyped by a sequenome mass spectrometry-based genotyping assay in 173 NSCLCs and the associations with TP53 mutations in the entire coding exons (exons 2-11), including splicing sites of the gene, were analyzed. Four SNPs (XPA rs1800975, OGG1 rs1052133, ADPRT rs1136410, and NBS1 rs1805794) were significantly associated with the prevalence of TP53 mutations in multivariate analysis for each SNP. When the 4 SNPs were combined, the prevalence of TP53 mutations was increased as the number of bad genotypes increased (P(trend)=0.001). Patients with 3 and 4 bad genotypes had a significantly higher frequency of TP53 mutations than those with 0-1 bad genotypes (adjusted odds ratio=5.18, 95% confidence interval=1.51-17.81, P=0.01 and adjusted odds ratio=18.26, 95% confidence interval=2.87-116.09, P=0.002, respectively). These findings suggest that the 4 SNPs may modulate the occurrence of TP53 mutations and contribute to lung carcinogenesis. However, larger studies are required to confirm our findings in other ethnic populations.

A Functional Variant at 19q13.3, rs967591G>A, Is Associated with Shorter Survival of Early-Stage Lung Cancer

Purpose: This study was conducted to investigate the associations between single-nucleotide polymorphisms (SNP) in 19q13.3 and survival of patients with early-stage non–small cell lung cancer (NSCLC), and to define the causative functional SNP of the association. Experimental Design: A two-stage study design was used to evaluate five SNPs in relation to survival outcomes in 328 patients and then to validate the results in an independent patient population (n = 483). Luciferase assay and real-time PCR were conducted to examine functional relevance of a potentially functional SNP. Results: Of the five SNPs, three SNPs (rs105165C>T, rs967591G>A, and rs735482A>C) were significantly associated with survival outcomes in a stage I study. The rs967591A allele had significantly higher activity of the CD3EAP promoter compared with the rs967591G allele (P = 0.002), but the SNP did not have an effect on the activity of PPP1R13L promoter. The rs967591G>A was associated with the level of CD3EAP mRNA expression in lung tissues (P = 0.01). The rs967591G>A exhibited consistent associations in a stage II study. In combined analysis, the rs967591 AA genotype exhibited a worse overall survival (adjusted HR = 1.69; 95% confidence interval = 1.29–2.20; P = 0.0001). Conclusion: The rs967591G>A affects CD3EAP expression and thus influences survival in early-stage NSCLC. The analysis of the rs967591G>A polymorphism can help identify patients at high risk of a poor disease outcome. Clin Cancer Res; 19(15); 4185–95. ©2013 AACR.