Kofi Asomaning

Circulating 25-Hydroxyvitamin D Levels Predict Survival in Early-Stage Non–Small-Cell Lung Cancer Patients

PURPOSE Our previous analyses suggested that surgery in the summertime with higher vitamin D intake is associated with improved survival in patients with early-stage non-small-cell lung cancer (NSCLC). We further investigated the results of circulating 25-hydroxyvitamin D (25[OH]D) levels on overall survival (OS) and recurrence-free survival (RFS) in NSCLC patients. PATIENTS AND METHODS Among 447 patients with early-stage NSCLC, data were analyzed using Cox proportional hazards models, adjusting for age, sex, stage, smoking, and treatment. RESULTS The median follow-up time was 72 months (range, 0.2 to 141), with 161 recurrences and 234 deaths. For OS, the adjusted hazard ratio (AHR) was 0.74 (95% CI, 0.50 to 1.10; Ptrend = .07) for the highest versus lowest quartile of 25(OH)D levels. Stratified by stage, a strong association was observed among stage IB-IIB patients (AHR, 0.45; 95% CI, 0.24 to 0.82; Ptrend = .002), but not among stage IA patients (AHR, 1.10; 95% CI, 0.62 to 1.96; Ptrend = .53). Similar effects of 25(OH)D levels were observed among the 309 patients with dietary information (AHR, 0.74; 95% CI, 0.46 to 1.17; Ptrend = .19). For the joint effects of 25(OH)D level and vitamin D intake, the combined high 25(OH)D levels and high vitamin D intake (by median) were associated with better survival than the combined low 25(OH)D levels and low vitamin D intake (AHR, 0.64; 95% CI, 0.42 to 0.98; Ptrend = .06). Again, stronger associations were observed among stage IB-IIB than IA patients. Similar effects of 25(OH)D levels and vitamin D intake were observed for RFS. CONCLUSION Vitamin D may be associated with improved survival of patients with early-stage NSCLC, particularly among stage IB-IIB patients.

VEGF Polymorphisms and Survival in Early-Stage Non–Small-Cell Lung Cancer

PURPOSE Polymorphisms in the VEGF gene have been identified that are believed to have functional activity. We hypothesized that such polymorphisms may affect survival outcomes among early-stage non-small-cell lung cancer (NSCLC) patients. PATIENTS AND METHODS We evaluated the relationship between VEGF polymorphisms and overall survival (OS) among patients with early-stage NSCLC treated with surgical resection at Massachusetts General Hospital from 1992 to 2001. We specifically investigated the VEGF polymorphisms +936C>T (rs3025039), -460T>C (rs833061), and +405G>C (rs2010963). Analyses of genotype associations with survival outcomes were performed using Cox proportional hazards models, Kaplan-Meier methods, and the log-rank test. RESULTS There were 462 patients and 237 deaths. Patients carrying the variant C allele of the VEGF +405G>C polymorphism had significantly improved survival (crude hazard ratio [HR] = 0.70; 95% CI, 0.54 to 0.90; P = .006; adjusted HR = 0.70; 95% CI, 0.54 to 0.91; P = .008). Five-year OS for patients carrying the variant C allele of the VEGF +405G>C polymorphism was 61% (95% CI, 54% to 67%) versus 51% (95% CI, 43% to 59%) for those who had the wild-type variant. There was a trend toward improved survival among patients carrying the variant T allele of the VEGF +936C>T polymorphism (crude HR = 0.74; 95% CI, 0.53 to 1.03; P = .07; adjusted HR = 0.73; 95% CI, 0.52 to 1.03; P = .07). Moreover, patients with higher number of variant alleles of the +405G>C and +936C>T polymorphisms had better survival. There was no association found with the -460T>C polymorphism. CONCLUSION Polymorphisms in VEGF may affect survival in early-stage lung cancer.

Genetic Variants on 15q25.1, Smoking, and Lung Cancer: An Assessment of Mediation and Interaction

Genome-wide association studies have identified variants on chromosome 15q25.1 that increase the risks of both lung cancer and nicotine dependence and associated smoking behavior. However, there remains debate as to whether the association with lung cancer is direct or is mediated by pathways related to smoking behavior. Here, the authors apply a novel method for mediation analysis, allowing for gene-environment interaction, to a lung cancer case-control study (1992-2004) conducted at Massachusetts General Hospital using 2 single nucleotide polymorphisms, rs8034191 and rs1051730, on 15q25.1. The results are validated using data from 3 other lung cancer studies. Tests for additive interaction (P = 2 × 10(-10) and P = 1 × 10(-9)) and multiplicative interaction (P = 0.01 and P = 0.01) were significant. Pooled analyses yielded a direct-effect odds ratio of 1.26 (95% confidence interval (CI): 1.19, 1.33; P = 2 × 10(-15)) for rs8034191 and an indirect-effect odds ratio of 1.01 (95% CI: 1.00, 1.01; P = 0.09); the proportion of increased risk mediated by smoking was 3.2%. For rs1051730, direct- and indirect-effect odds ratios were 1.26 (95% CI: 1.19, 1.33; P = 1 × 10(-15)) and 1.00 (95% CI: 0.99, 1.01; P = 0.22), respectively, with a proportion mediated of 2.3%. Adjustment for measurement error in smoking behavior allowing up to 75% measurement error increased the proportions mediated to 12.5% and 9.2%, respectively. These analyses indicate that the association of the variants with lung cancer operates primarily through other pathways.

Epidermal growth factor receptor polymorphisms and clinical outcomes in non-small-cell lung cancer patients treated with gefitinib

The−216G/T, −191C/A, intron 1 and Arg497Lys epidermal growth factor receptor (EGFR) polymorphisms were evaluated in 92 advanced non-small-cell lung cancer patients treated with gefitinib, an EGFR tyrosine-kinase inhibitor. Improved progression free survival (PFS) was found in patients homozygous for the shorter lengths of intron 1 polymorphism (S/S; S=16 or fewer CA repeats; log-rank test (LRT) P=0.03) and for patients carrying any T allele of the −216G/T polymorphism (LRT, P=0.005). When considered together, patients with intron 1 S/S genotype and at least one T allele of −216G/T had improved PFS (LRT P=0.0006; adjusted hazard ratio (AHR), 0.60 (95% confidence interval, 0.36–0.98)) and overall survival (LRT P=0.02; AHR, 0.60 (0.36–1.00)) when compared with all others. The T allele of −216G/T was also associated with significantly higher rates of stable disease/partial response (P=0.01) and a significantly higher risk of treatment-related rash/diarrhea (P=0.004, multivariate model). EGFR intron 1 and –216G/T polymorphisms influence clinical outcomes in gefitinib-treated non-small-cell lung cancer patients.

Circulating 25-Hydroxyvitamin D, VDR Polymorphisms, and Survival in Advanced Non–Small-Cell Lung Cancer

PURPOSE We showed previously that in early-stage non-small-cell lung cancer (NSCLC), serum vitamin D levels and VDR polymorphisms were associated with survival. We hypothesized that vitamin D levels and VDR polymorphisms may also affect survival among patients with advanced NSCLC. PATIENTS AND METHODS We evaluated the relationship between circulating 25-hydroxyvitamin D levels; VDR polymorphisms, including Cdx-2 G>A (rs11568820), FokI C>T (rs10735810), and BsmI C>T (rs144410); and overall survival among patients with advanced NSCLC. Analyses of survival outcomes were performed using the log-rank test and Cox proportional hazards models, adjusting for sex, stage, and performance status. RESULTS There were 294 patients and 233 deaths, with median follow-up of 42 months. We found no difference in survival by circulating vitamin D level. The C/C genotype of the FokI polymorphism was associated with improved survival: median survival for C/C was 21.4 months, for C/T was 12.1 months, and for T/T was 15.6 months (log-rank P = .005). There were no significant effects on survival by the Cdx-2 or BsMI polymorphism. However, having increasing numbers of protective alleles was associated with improved survival (adjusted hazard ratio for two or more v zero to one protective alleles, 0.57; 95% CI, 0.41 to 0.79; P = .0008). On haplotype analysis, the G-T-C (Cdx-2-FokI-BsmI) haplotype was associated with worse survival compared with the most common haplotype of G-C-T (adjusted hazard ratio, 1.61; 95% CI, 1.21 to 2.14; P = .001). CONCLUSION There was no main effect of vitamin D level on overall survival in the advanced NSCLC population. The T allele of the VDR FokI>T polymorphism and the G-T-C (Cdx-2-FokI-BsmI) haplotype were associated with worse survival.

Genome-Wide Analysis of Survival in Early-Stage Non–Small-Cell Lung Cancer

PURPOSE Lung cancer, of which 85% is non-small-cell (NSCLC), is the leading cause of cancer-related death in the United States. We used genome-wide analysis of tumor tissue to investigate whether single nucleotide polymorphisms (SNPs) in tumors are prognostic factors in early-stage NSCLC. PATIENTS AND METHODS One hundred early-stage NSCLC patients from Massachusetts General Hospital (MGH) were used as a discovery set and 89 NSCLC patients collected by the National Institute of Occupational Health, Norway, were used as a validation set. DNA was extracted from flash-frozen lung tissue with at least 70% tumor cellularity. Genome-wide genotyping was done using the high-density SNP chip. Copy numbers were inferred using median smoothing after intensity normalization. Cox models were used to screen and validate significant SNPs associated with the overall survival. RESULTS Copy number gains in chromosomes 3q, 5p, and 8q were observed in both MGH and Norwegian cohorts. The top 50 SNPs associated with overall survival in the MGH cohort (P < or = 2.5 x 10(-4)) were selected and examined using the Norwegian cohort. Five of the top 50 SNPs were validated in the Norwegian cohort with false discovery rate lower than 0.05 (P < .016) and all five were located in known genes: STK39, PCDH7, A2BP1, and EYA2. The numbers of risk alleles of the five SNPs showed a cumulative effect on overall survival (P(trend) = 3.80 x 10(-12) and 2.48 x 10(-7) for MGH and Norwegian cohorts, respectively). CONCLUSION Five SNPs were identified that may be prognostic of overall survival in early-stage NSCLC.

A Functional Epidermal Growth Factor (EGF) Polymorphism, EGF Serum Levels, and Esophageal Adenocarcinoma Risk and Outcome

Purpose: The epidermal growth factor (EGF) pathway is important in esophageal adenocarcinoma (EAC) tumorigenesis. We hypothesized that the EGF A61G homozygous variant genotype (GG) is (a) both a risk and poor prognostic factor for EAC and (b) associated with higher EGF serum levels in individuals with gastroesophageal reflux disease (GERD). Experimental Design: Using unconditional logistic regression, we compared EGF A61G in 312 EAC cases and 447 GERD-free controls, adjusting for age, gender, smoking history, and healthy adult body mass index. Using the method of Kaplan and Meier, log-rank tests, and Cox proportional hazard models, we correlated EGF A61G with overall and failure-free survival in the EAC cases. Serum EGF levels and EGF genotype (G/G versus others) were correlated in 144 GERD patients using Wilcoxon rank sum tests. Results: The EGF A61G G/G genotype conferred increased EAC risk, with an adjusted odds ratio of 1.81 (95% confidence interval, 1.2-2.7), and was even higher in the subgroup of EAC patients with concurrent Barretts esophagus (adjusted odds ratio, 2.18; 95% confidence interval, 1.3-3.7). However, EGF A61G was not associated with a more aggressive phenotype or prognosis in EAC patients. Higher serum EGF levels were found in GERD patients carrying G/G compared with A/A or A/G (P = 0.03, Wilcoxon rank sum test). Conclusion: The EGF A61G G/G genotype is associated with a near 2-fold greater risk of EAC. The G/G allele was also associated with higher EGF levels in tumor-free patients with GERD. EGF genotyping can potentially identify high-risk patients with GERD and Barretts metaplasia who might benefit from increased surveillance.

Vascular Endothelial Growth Factor Genotypes, Haplotypes, Gender, and the Risk of Non–Small Cell Lung Cancer

Purpose: The vascular endothelial growth factor (VEGF) is a major mediator of angiogenesis involving tumor growth and metastasis. Polymorphisms in the VEGF gene may regulate VEGF production. In this large case-control study, we investigated whether functional polymorphisms (−460C/T, +405C/G, +936C/T) in the VEGF gene are associated with the risk of non–small cell lung cancer (NSCLC). Experimental Design:VEGF genotypes and haplotypes were determined in 1,900 Caucasian patients with NSCLC and 1,458 healthy controls. The results were analyzed using logistic regression models, adjusting for age, gender, smoking status, pack-years of smoking, and years since smoking cessation (for ex-smokers). The false-positive report probability was estimated for the observed odds ratios (OR). Results: There were no overall associations between individual VEGF genotypes and the risk of NSCLC. Stratified analysis suggested that the combined +405CC+CG genotype was significantly associated with increased risk of lung adenocarcinoma in males (adjusted OR, 1.40; 95% confidence interval, 1.03-1.87). In haplotype analysis, haplotypes were globally associated with differences between cases and controls in males (P = 0.03). Specifically, the −460T/+405G/+936C haplotype was significantly (P = 0.02) associated with decreased risk of adenocarcinoma in males when compared with the most common CGC haplotype (adjusted OR, 0.76; 95% confidence interval, 0.50-0.98). None of the VEGF genotypes and haplotypes studied significantly influenced the susceptibility to NSCLC in females. Conclusions: Polymorphisms of −460C/T, +405C/G, and +936C/T in the VEGF gene do not play a major role in NSCLC risk. However, we could not exclude a minor role for the +405CC+CG genotypes and the 460T/+405G/+936C haplotype in lung adenocarcinogenesis in male Caucasians.

Cisplatin pharmacogenetics, DNA repair polymorphisms, and esophageal cancer outcomes

Objectives Genetic variations or polymorphisms within genes of the nucleotide excision repair (NER) pathway alter DNA repair capacity. Reduced DNA repair (NER) capacity may result in tumors that are more susceptible to cisplatin chemotherapy, which functions by causing DNA damage. We investigated the potential predictive significance of functional NER single nucleotide polymorphisms in esophageal cancer patients treated with (n = 262) or without (n = 108) cisplatin. Methods Four NER polymorphisms XPD Asp312Asn; XPD Lys751Gln, ERCC1 8092C/A, and ERCC1 codon 118C/T were each assessed in polymorphism–cisplatin treatment interactions for overall survival (OS), with progression-free survival (PFS) as a secondary endpoint. Results No associations with ERCC1 118 were found. Polymorphism–cisplatin interactions were highly significant in both OS (P = 0.002, P = 0.0001, and P<0.0001) and PFS (P = 0.006, P = 0.008, and P = 0.0007) for XPD 312, XPD 751, and ERCC1 8092, respectively. In cisplatin-treated patients, variant alleles of XPD 312, XPD 751, and ERCC1 8092 were each associated with significantly improved OS (and PFS): adjusted hazard ratios of homozygous variants versus wild-type ranged from 0.22 [95% confidence interval (CI): 0.1–0.5] to 0.31 (95% CI: 0.1–0.7). In contrast, in patients who did not receive cisplatin, variant alleles of XPD 751 and ERCC1 8092 had significantly worse survival, with adjusted hazard ratios of homozygous variants ranging from 2.47 (95% CI: 1.1–5.5) to 3.73 (95% CI: 1.6–8.7). Haplotype analyses affirmed these results. Conclusion DNA repair polymorphisms are associated with OS and PFS, and if validated may predict for benefit from cisplatin therapy in patients with esophageal cancer.

Second hand smoke, age of exposure and lung cancer risk

BACKGROUND Exposure to second hand smoke (SHS) has been identified as a risk factor for lung cancer for three decades. It is also known that the lung continues to grow from birth to adulthood, when lung growth stops. We hypothesize that after adjusting for active cigarette smoking, if SHS exposure took place during the period of growth, i.e. in the earlier part of life (0-25 years of age) the risk of lung cancer is greater compared to an exposure occurring after age 25. METHOD Second hand smoke exposure was self-reported for three different activities (leisure, work and at home) for this study population of 1669 cases and 1263 controls. We created variables that captured location of exposure and timing of first exposure with respect to a study participants age (0-25, >25 years of age). Multiple logistic regressions were used to study the association between SHS exposure and lung cancer, adjusting for age, gender and active smoking variables. RESULT For study participants that were exposed to SHS at both activities (work and leisure) and compared to one or no activity, the adjusted odds ratio (AOR) for lung cancer was 1.30 (1.08-1.57) when exposure occurred between birth and age 25 and 0.66 (0.21-1.57) if exposure occurred after age 25 years. Respective results for non-smokers were 1.29 (0.82-2.02) and 0.87 (0.22-3.38), and current and ex-smokers combined 1.28 (1.04-1.58) and 0.66 (0.15-2.85). CONCLUSION All individuals exposed to SHS have a higher risk of lung cancer. Furthermore, this study suggests that subjects first exposed before age 25 have a higher lung cancer risk compared to those for whom first exposure occurred after age 25 years.