Associations of lung cancer risk with biomarkers of Helicobacter pylori infection.

Helicobacter pylori infection has been suggested to be associated with lung cancer risk. However, information is lacking on whether the association differs by H. pylori antigen. We conducted a nested case-control study within the Southern Community Cohort Study, including 295 incident lung cancer cases and 295 controls. Helicobacter pylori multiplex serology assay was performed to detect antibodies to 15 H. pylori proteins. Conditional logistic regression was used to estimate odds ratios (ORs) and confidence intervals (95% CIs) after adjustment for covariates. Overall H. pylori+ was associated with a non-statistically significant increased risk of lung cancer (OR: 1.29; 95% CI: 0.85-1.95). Significant associations, however, were observed for H. pylori+ VacA+ (OR: 1.64; 95% CI: 1.02-2.62) and H. pylori+ Catalase+ (OR: 1.75; 95% CI: 1.11-2.77). The positive association of H. pylori+ Catalase+ with lung cancer risk was predominantly seen among African Americans (OR: 2.09; 95% CI: 1.11-3.95) but not European Americans (OR: 1.20; 95% CI: 0.56-2.54). Among participants who smoked ≥ 30 pack-years, overall H. pylori+ (OR: 1.85; 95% CI: 1.02-3.35), H. pylori+ CagA+ (OR: 2.77; 95% CI: 1.35-5.70), H. pylori+ VacA+ (OR: 2.53; 95% CI: 1.25-5.13) and H. pylori+ HP1564+ (OR: 2.01; 95% CI: 1.07-3.77) were associated with increased risk of lung cancer. Our study provides novel evidence that associations of H. pylori infection with lung cancer risk differ by H. pylori biomarker, may be more evident among African Americans and may be modified by smoking habits. Furthermore, studies are warranted to confirm our findings.

Association of oral microbiota with lung cancer risk in a low-income population in the Southeastern USA.

PURPOSE: Oral microbiome plays an important role in oral health and systemic diseases, including cancer. We aimed to prospectively investigate the association of oral microbiome with lung cancer risk. METHODS: We analyzed 156 incident lung cancer cases (73 European Americans and 83 African Americans) and 156 individually matched controls nested within the Southern Community Cohort Study. Oral microbiota were assessed using 16S rRNA gene sequencing in pre-diagnostic mouth rinse samples. Paired t test and the permutational multivariate analysis of variance test were used to evaluate lung cancer risk association with alpha diversity or beta diversity, respectively. Conditional logistic regression models were used to evaluate the association of individual bacterial abundance or prevalence with lung cancer risk. RESULTS: No significant differences were observed for alpha or beta diversity between lung cancer cases and controls. Abundance of families Lachnospiraceae_[XIV], Peptostreptococcaceae_[XI], and Erysipelotrichaceae and species Parvimonas micra was associated with decreased lung cancer risk, with odds ratios (ORs) and 95% confidence intervals (CIs) of 0.76 (0.59-0.98), 0.80 (0.66-0.97), 0.81 (0.67-0.99), and 0.83 (0.71-0.98), respectively (all p < 0.05). Prevalence of five pre-defined oral pathogens were not significantly associated with overall lung cancer risk. Prevalence of genus Bacteroidetes_[G-5] and species Alloprevotella sp._oral_taxon_912, Capnocytophaga sputigena, Lactococcus lactis, Peptoniphilaceae_[G-1] sp._oral_taxon_113, Leptotrichia sp._oral_taxon_225, and Fretibacterium fastidiosum was associated with decreased lung cancer risk, with ORs and 95% CIs of 0.55 (0.30-1.00), 0.36 (0.17-0.73), 0.53 (0.31-0.92), 0.43 (0.21-0.88), 0.43 (0.19-0.94), 0.57 (0.34-0.99), and 0.54 (0.31-0.94), respectively (all p < 0.05). Species L. sp._oral_taxon_225 was significantly associated with decreased lung cancer risk in African Americans (OR [95% CIs] 0.28 [0.12-0.66]; p = 0.00012). CONCLUSION: Results from this study suggest that oral microbiota may play a role in the development of lung cancer.

Identification of Susceptibility Loci and Genes for Colorectal Cancer Risk.

BACKGROUND & AIMS: Known genetic factors explain only a small fraction of genetic variation in colorectal cancer (CRC). We conducted a genome-wide association study to identify risk loci for CRC. METHODS: This discovery stage included 8027 cases and 22,577 controls of East-Asian ancestry. Promising variants were evaluated in studies including as many as 11,044 cases and 12,047 controls. Tumor-adjacent normal tissues from 188 patients were analyzed to evaluate correlations of risk variants with expression levels of nearby genes. Potential functionality of risk variants were evaluated using public genomic and epigenomic databases. RESULTS: We identified 4 loci associated with CRC risk; P values for the most significant variant in each locus ranged from 3.92 × 10(-8) to 1.24 × 10(-12): 6p21.1 (rs4711689), 8q23.3 (rs2450115, rs6469656), 10q24.3 (rs4919687), and 12p13.3 (rs11064437). We also identified 2 risk variants at loci previously associated with CRC: 10q25.2 (rs10506868) and 20q13.3 (rs6061231). These risk variants, conferring an approximate 10%-18% increase in risk per allele, are located either inside or near protein-coding genes that include transcription factor EB (lysosome biogenesis and autophagy), eukaryotic translation initiation factor 3, subunit H (initiation of translation), cytochrome P450, family 17, subfamily A, polypeptide 1 (steroidogenesis), splA/ryanodine receptor domain and SOCS box containing 2 (proteasome degradation), and ribosomal protein S2 (ribosome biogenesis). Gene expression analyses showed a significant association (P < .05) for rs4711689 with transcription factor EB, rs6469656 with eukaryotic translation initiation factor 3, subunit H, rs11064437 with splA/ryanodine receptor domain and SOCS box containing 2, and rs6061231 with ribosomal protein S2. CONCLUSIONS: We identified susceptibility loci and genes associated with CRC risk, linking CRC predisposition to steroid hormone, protein synthesis and degradation, and autophagy pathways and providing added insight into the mechanism of CRC pathogenesis.

Associations between Plasma Tocopherols and Lung Cancer Risk: Results from the Southern Community Cohort Study.

BACKGROUND: Despite the various anticancer activities of tocopherols, little is known about tocopherols associated with lung cancer risk among low-income African Americans (AA) and European Americans (EA) who are disproportionately affected by the disease. METHODS: We conducted a nested case-control study that included 209 incident lung cancer cases and 406 matched controls within the Southern Community Cohort Study. Using biospecimens collected at cohort enrollment, plasma levels of α-, ß/γ-, δ-, and total-tocopherols were measured by high-performance liquid chromatography with photodiode array detection. Conditional logistic regression was used to estimate ORs and 95% confidence intervals (CI) for lung cancer risk after adjusting for potential confounders. Stratified analyses were also conducted. RESULTS: Plasma levels of total-tocopherols were inversely associated with lung cancer risk overall [OR (95% CI) for the highest vs. lowest tertile = 0.51 (0.30-0.90)]. The inverse association remained significant among EAs [0.20 (0.06-0.65)], men [0.43 (0.21-0.90)], current smokers [0.49 (0.26-0.93)], and cases diagnosed within 2 years of blood draw [0.36 (0.15-0.86)], though we did not find a significant risk reduction among AAs [0.75 (0.39-1.45)]. Notably, we found significant interactions between α-tocopherol and race after controlling the FDR to correct for multiple comparisons (Pinteraction = 0.02). CONCLUSIONS: Our results indicate that plasma total-tocopherols are inversely associated with lung cancer risk, but the association may differ across specific isomeric forms of tocopherols, race, or other individuals' characteristics. Further large-scale studies are warranted to confirm our findings. IMPACT: Recommendations on tocopherols for lung cancer prevention should take isomers, race, and smoking behaviors into consideration.

Association of a single nucleotide polymorphism at 6q25.1,rs2046210, with endometrial cancer risk among Chinese women.

A recent genome-wide association study identified a new susceptibility locus for breast cancer, rs2046210, which is a single nucleotide polymorphism (SNP) located upstream of the estrogen receptor α(ESR1) gene on chromosome 6q25.1. Given that endometrial cancer shares many risk factors with breast cancer and both are related to estrogen exposure and that rs2046210 is in close proximity to the ESR1 gene, we evaluated the association of SNP rs2046210 with endometrial cancer risk among 953 cases and 947 controls in a population-based, case-control study conducted in Shanghai, China. Logistic regression models were used to derive odds ratios (ORs) and 95% confidence intervals (95% CIs) after adjusting for potential confounders. We found that the A allele of rs2046210, linked to an increased risk of breast cancer, was associated with increased but not statistically significant risk of endometrial cancer (OR = 1.16, 95% CI = 0.96-1.41 for the GA and AA genotypes compared with the GG genotype); the association was stronger among post-menopausal women (OR = 1.28, 95% CI = 1.00-1.65). The association tended to be stronger among women with higher or longer estrogen exposure than among women with relatively lower or shorter exposure to estrogen. Our study suggests that rs2046210 may play a role in the etiology of endometrial cancer. Additional studies are needed to confirm our findings.

Mutations in the mitochondrial DNA D-loop region and breast cancer risk.

Mitochondrial genome alterations have been suggested to play an important role in carcinogenesis. The D-loop region of mitochondrial DNA (mtDNA) contains essential transcription and replication elements, and mutations in this region may serve as a potential sensor for cellular DNA damage and a marker for cancer development. Using data and samples from the Shanghai Breast Cancer Study, we investigated MnlI restriction sites located between nucleotides 16,106 and 16,437 of the mtDNA D-loop region to evaluate restriction fragment length polymorphism (RFLP) patterns in tumor tissue from 501 primary breast cancer patients when compared with tumor tissue from 203 women with benign breast disease (BBD). RFLP patterns in correspondingly paired, adjacent, non-tumor tissues taken from 120 primary breast cancer patients and 59 BBD controls were also evaluated. Five common RFLP patterns were observed, and no significant differences were observed in the distribution of these patterns between tumor and adjacent non-tumor tissue samples from breast cancer patients and tissue samples from BBD controls. On the other hand, somatic MnlI site mutations, defined as a difference in MnlI RFLP pattern between tumor tissue and the corresponding, adjacent, non-tumor tissue, occurred more frequently in breast cancer patients (28.3%) than in BBD patients (15.3%) (P = 0.05) and more frequently in proliferative BBD (13.0%) than in non-proliferative BBD (7.1%). Our data suggest that somatic MnlI site mutations may play a role in the pathogenesis of breast cancer.

The EGFR polymorphism rs884419 is associated with freedom from recurrence in patients with resected prostate cancer.

PURPOSE: Prognostic biomarkers are needed to optimize treatment decisions for prostate cancer. Single nucleotide polymorphisms participate in the individual genetic background modulating risk and clinical outcomes of cancer. We tested whether EGFR polymorphisms are associated with prostate cancer clinical outcomes. MATERIALS AND METHODS: The study population consisted of 212 patients with clinically localized prostate cancer treated with radical prostatectomy from 1997 to 1999. Resected prostatic tissues were genotyped with allele specific probes for 9 haplotype tagging single nucleotide polymorphisms, which were located in intronic, exonic and flanking regions of linkage disequilibrium in the EGFR gene. Correlations between alleles, and recurrence and survival data were investigated using univariate and multivariate genetic analysis models. RESULTS: There was a statistically significant association between the single nucleotide polymorphism rs884419 and prostate cancer recurrence, as defined in the study by at least prostate specific antigen biochemical recurrence (log rank test p <0.001). The incidence of the recurrence risk enhancing genotype A/A was 3.1% vs 17.4% and 80% for the risk decreasing genotypes A/G G/G, respectively. Based on Cox proportional hazard regression modeling patients carrying G/G and A/G genotypes were associated with a decreased risk of prostate cancer recurrence compared to those with the A/A genotype (HR 0.10, 95% CI 0.02-0.41 and 0.13, 95% CI 0.04-0.46, respectively, p <0.002). CONCLUSIONS: These data suggest that a polymorphism flanking the EGFR gene is an independent prognostic genetic biomarker that predicts prostate cancer biochemical recurrence after radical prostatectomy.

Cancer-associated immunodeficiency and dendritic cell abnormalities mediated by the prostaglandin EP2 receptor.

Prostaglandin E(2) (PGE(2)), a major COX metabolite, plays important roles in several facets of tumor biology. We characterized the contribution of the PGE(2) EP2 receptor to cancer-associated immune deficiency using EP2(-/-) mice. EP2(-/-) mice exhibited significantly attenuated tumor growth and longer survival times when challenged with MC26 or Lewis lung carcinoma cell lines as compared with their wild-type littermates. While no differences in T cell function were observed, PGE(2) suppressed differentiation of DCs from wild-type bone marrow progenitors, whereas EP2-null cells were refractory to this effect. Stimulation of cells in mixed lymphocyte reactions by wild-type DCs was suppressed by treatment with PGE(2), while EP2(-/-)-derived DCs were resistant to this effect. In vivo, DCs, CD4(+), and CD8(+) T cells were significantly more abundant in draining lymph nodes of tumor-bearing EP2(-/-) mice than in tumor-bearing wild-type mice, and a significant antitumor cytotoxic T lymphocyte response could be observed only in the EP2(-/-) animals. Our data demonstrate an important role for the EP2 receptor in PGE(2)-induced inhibition of DC differentiation and function and the diminished antitumor cellular immune responses in vivo.

Association of leukocyte mitochondrial DNA copy number with colorectal cancer risk: Results from the Shanghai Women's Health Study.

BACKGROUND: Mitochondria play an important role in cellular energy metabolism, free radical production, and apoptosis, and thus may be involved in cancer development. METHODS: We evaluated mitochondrial DNA (mtDNA) copy number in peripheral leukocytes in relation to colorectal cancer risk in a case-control study of 444 colorectal cancer cases and 1,423 controls nested in the Shanghai Women's Health Study, a population-based, prospective cohort study. Relative mtDNA copy number was determined by a quantitative real-time PCR assay using peripheral leukocyte DNA samples collected at the time of study enrollment, before cancer diagnosis. RESULTS: We found that baseline mtDNA copy number was lower among women who subsequently developed colorectal cancer [geometric mean, 0.277; 95% confidence interval (CI), 0.269-0.285] than among women who remained cancer-free (geometric mean, 0.288; 95% CI, 0.284-0.293; P = 0.0153). Multivariate adjusted ORs were 1.26 (95% CI, 0.93-1.70) and 1.44 (95% CI, 1.06-1.94) for the middle and lower tertiles of mtDNA copy number, respectively, compared with the upper tertile (highest mtDNA copy number; Ptrend = 0.0204). The association varied little by the interval between blood collection and cancer diagnosis. CONCLUSIONS: Our data suggest that mtDNA copy number measured in peripheral leukocytes may be a potential biomarker useful for colorectal cancer risk assessment. IMPACT: If confirmed, mtDNA copy number measured in peripheral leukocytes may be a biomarker useful for colorectal cancer risk assessment.

An evaluation of allele frequency estimation accuracy using pooled sequencing data.

Next generation sequencing technology has matured, and with its current affordability, will replace the SNP chip as the genotyping tool of choice. Even with the current affordability of NGS, large scale studies will require careful study design to reduce cost. In this study, we designed an experiment to assess the accuracy of allele frequency estimated from pooled sequencing data. We compared the allele frequency estimated from sequencing data with the allele frequency estimated from individual SNP chip data and observed high correlations between them. However, by calculating error rate, we found that many SNPs had their allele frequency estimated from sequencing data significantly different from allele frequency estimated from SNP chip data. In conclusion, we found correlation is not an ideal measurement for comparing allele frequencies. And for the purpose of estimating allele frequency, we do not recommend using pooling with NGS as a cheaper alternative to genotype each sample individually.

Quantitative analysis of mitochondrial DNA 4977-bp deletion in sporadic breast cancer and benign breast diseases.

The mitochondrial DNA (mtDNA) 4977-bp deletion (DeltamtDNA(4977) mutation) is one of the most frequently observed mtDNA mutations in human tissues and may play a role in carcinogenesis. Only a few studies have evaluated DeltamtDNA(4977) mutation in breast cancer tissue, and the findings have been inconsistent, which may be due to methodological differences. In this study, we developed a quantitative real-time PCR assay to assess the level of the DeltamtDNA(4977) mutation in tumor tissue samples from 55 primary breast cancer patients and 21 patients with benign breast disease (BBD). The DeltamtDNA(4977) mutation was detected in all of the samples with levels varying from 0.000149% to 7.0%. The DeltamtDNA(4977) mutation levels were lower in tumor tissues than in adjacent normal tissues in both breast cancer and BBD subjects. The differences, however, were not statistically significant. No significant difference between breast cancer and BBD patients was found in the DeltamtDNA(4977) mutation levels of tumor tissues and adjacent normal tissues. The DeltamtDNA(4977) mutation levels were not significantly associated with clinicopathological characteristics (age, histology, tumor stage, and ER/PR status) in breast cancer or BBD patients. These results do not support the notion that the mitochondrial DNA 4977-bp deletion plays a major role in breast carcinogenesis.

Interaction of soy and 17beta-HSD1 gene polymorphisms in the risk of endometrial cancer.

BACKGROUND: In-vitro studies have found that soy isoflavones can inhibit the activity of 17beta-hydroxysteroid dehydrogenase type I, a key enzyme in catalyzing estrone (E1), to the biologically more active estradiol (E2). OBJECTIVE: We hypothesized that soy food consumption may interact with polymorphisms in the 17beta-HSD1 gene in the development of endometrial cancer and evaluated this hypothesis in the Shanghai Endometrial Cancer Study. METHODS: Shanghai Endometrial Cancer Study is a population-based case-control study conducted among Chinese women in Shanghai. This study consisted of 1204 incident endometrial cancer cases diagnosed between 30 and 69 years of age and 1212 age frequency-matched community controls recruited from 1997 to 2003. Overall participation rates were 82.8% for cases and 74.4% for controls, whereas the DNA collection rates were 95.1% for cases and 94.2% for controls. RESULTS: We found that women carrying at least one A allele of the rs605059 polymorphism had a significant 18% reduction in risk of endometrial cancer compared with those without an A allele, and the association was primarily restricted to premenopausal women. The odds ratio (95% confidence interval) was 0.65 (0.47-0.88) for premenopausal women with at least one A allele versus those without an A allele. We also found that among premenopausal women soy isoflavone intake significantly interacted with the rs605059 genotype in relation to endometrial cancer and that the inverse association between soy isoflavone intake and endometrial cancer only appeared among those with at least one A allele of the rs605059 polymorphism. Among postmenopausal women, the association of soy isoflavone intake with endometrial cancer did not differ by 17beta-HSD1 genotypes. We did not find that the rs2676530 polymorphism was significantly associated with endometrial cancer risk. CONCLUSIONS: Our results suggest that soy consumption may interact with polymorphisms in the 17beta-HSD1 gene in relation to endometrial cancer risk. Further studies are warranted to confirm our results.

ATM polymorphism IVS62+60G>A is not associated with disease aggressiveness in prostate cancer.

OBJECTIVES: ATM is an important protein that protects the genome from double-stranded DNA breaks. Mutations and polymorphisms in the ATM gene have been associated with an increased risk of certain types of malignancies, especially breast cancer. METHODS: We analyzed tissue from 98 white patients with prostate cancer for the presence of IVS62+60G>A polymorphism in the ATM gene. RESULTS: The frequency of the homozygous IVS62+60G/G, heterozygous IVS62+60G/A, and homozygous IVS62+60A/A was 18.37% (18 of 98), 30.61% (30 of 98), and 51.02% (50 of 98), respectively. Using Fisher's exact test, we found the polymorphism IVS62+60G>A was not significantly related to age, tumor grade, prostate-specific antigen level, or clinical stage (P >0.05). No difference was found in relapse-free survival between patients with IVS62+60G/G and those with IVS62+60G/A or IVS62+60A/A (P = 0.4533). CONCLUSIONS: The results of our study indicate that this ATM polymorphism is not associated with the aggressiveness of prostate cancer in white men.