D. J. Van Den Berg

Interaction between cyclooxygenase-2 gene polymorphism and dietary n-6 polyunsaturated fatty acids on colon cancer risk: the Singapore Chinese Health Study.

This case–control study of 310 colorectal cancer cases and 1177 controls in a nested prospective, population-based cohort of Singapore Chinese subjects found a statistically significant association between the cyclooxygenase (COX)-2 −765G>C gene polymorphism and colon cancer risk among high consumers of dietary n-6 polyunsaturated fatty acids (odds ratio=2.38, 95% confidence interval=1.23–4.59).

Validating genetic risk associations for ovarian cancer through the international Ovarian Cancer Association Consortium

The search for genetic variants associated with ovarian cancer risk has focused on pathways including sex steroid hormones, DNA repair, and cell cycle control. The Ovarian Cancer Association Consortium (OCAC) identified 10 single-nucleotide polymorphisms (SNPs) in genes in these pathways, which had been genotyped by Consortium members and a pooled analysis of these data was conducted. Three of the 10 SNPs showed evidence of an association with ovarian cancer at P⩽0.10 in a log-additive model: rs2740574 in CYP3A4 (P=0.011), rs1805386 in LIG4 (P=0.007), and rs3218536 in XRCC2 (P=0.095). Additional genotyping in other OCAC studies was undertaken and only the variant in CYP3A4, rs2740574, continued to show an association in the replication data among homozygous carriers: ORhomozygous(hom)=2.50 (95% CI 0.54-11.57, P=0.24) with 1406 cases and 2827 controls. Overall, in the combined data the odds ratio was 2.81 among carriers of two copies of the minor allele (95% CI 1.20–6.56, P=0.017, phet across studies=0.42) with 1969 cases and 3491 controls. There was no association among heterozygous carriers. CYP3A4 encodes a key enzyme in oestrogen metabolism and our finding between rs2740574 and risk of ovarian cancer suggests that this pathway may be involved in ovarian carcinogenesis. Additional follow-up is warranted.

A meta-analysis of Hodgkin lymphoma reveals 19p13.3 TCF3 as a novel susceptibility locus

Recent genome wide association studies (GWAS) of Hodgkin lymphoma (HL) have identified associations with genetic variation at both HLA and non-HLA loci; however, much of heritable HL susceptibility remains unexplained. Here we perform a meta-analysis of three HL GWAS totaling 1,816 cases and 7,877 controls followed by replication in an independent set of 1,281 cases and 3,218 controls to find novel risk loci. We identify a novel variant at 19p13.3 associated with HL (rs1860661; odds ratio [OR] = 0.81, 95% confidence interval [95% CI] = 0.76–0.86, Pcombined = 3.5 × 10−10), located in intron 2 of TCF3 (also known as E2A), a regulator of B- and T-cell lineage commitment known to be involved in HL pathogenesis. This meta-analysis also notes associations between previously published loci at 2p16.1, 5q31, 6p31.2, 8q24.21 and 10p14 and HL subtypes. We conclude that our data suggest a link between the 19p13.3 locus, including TCF3, and HL risk

Insulin-like growth factor-1 promoter polymorphisms and colorectal cancer: a functional genomics approach

Rationale: Insulin-like growth factor-1 (IGF1) has been proposed to mediate the obesity-related carcinogenic effects of “Western lifestyle”. While genetic factors explain at least half of inter-individual IGF1 variation, the IGF1 polymorphisms hypothesised to underlie the variation in cancer incidence rates remain ill-defined. Methods: We used a comparative genomics approach to identify putative regulatory polymorphisms in the IGF1 promoter region within a rapidly westernising population, the Singapore Chinese. Association of IGF1 genotype with colorectal cancer risk was assessed among 298 colorectal cancer cases and 1142 controls nested within the Singapore Chinese Health Study. Results: We identified a common (minor allele frequency = 0.36) single-nucleotide polymorphism (SNP), IGF1-2995 C/A, within a consensus domain for an octamer binding factor (Oct1/Oct2) transcription factor binding site. Possession of one or two copies of the minor allele (genotypes AA and CA) conferred an approximate 40% decrease in risk in comparison to genotype CC (odds ratio, 0.59; 95% confidence interval, 0.45 to 0.77). This association was stronger for colon cancer than for rectal cancer (pheterogeneity<0.001) and for those who were physically active versus inactive (pinteraction = 0.05). Models including other previously identified promoter polymorphisms did not provide a better prediction of colorectal cancer risk. Conclusions: Our results support the hypotheses that IGF1 plays a role in colonic carcinogenesis and that genetically inherited variation in IGF1 expression influences risk of colorectal cancer.

Tagging single-nucleotide polymorphisms in candidate oncogenes and susceptibility to ovarian cancer.

Low–moderate risk alleles that are relatively common in the population may explain a significant proportion of the excess familial risk of ovarian cancer (OC) not attributed to highly penetrant genes. In this study, we evaluated the risks of OC associated with common germline variants in five oncogenes (BRAF, ERBB2, KRAS, NMI and PIK3CA) known to be involved in OC development. Thirty-four tagging SNPs in these genes were genotyped in ∼1800 invasive OC cases and 3000 controls from population-based studies in Denmark, the United Kingdom and the United States. We found no evidence of disease association for SNPs in BRAF, KRAS, ERBB2 and PIK3CA when OC was considered as a single disease phenotype; but after stratification by histological subtype, we found borderline evidence of association for SNPs in KRAS and BRAF with mucinous OC and in ERBB2 and PIK3CA with endometrioid OC. For NMI, we identified a SNP (rs11683487) that was associated with a decreased risk of OC (unadjusted Pdominant=0.004). We then genotyped rs11683487 in another 1097 cases and 1792 controls from an additional three case–control studies from the United States. The combined odds ratio was 0.89 (95% confidence interval (CI): 0.80–0.99) and remained statistically significant (Pdominant=0.032). We also identified two haplotypes in ERBB2 associated with an increased OC risk (Pglobal=0.034) and a haplotype in BRAF that had a protective effect (Pglobal=0.005). In conclusion, these data provide borderline evidence of association for common allelic variation in the NMI with risk of epithelial OC.

Erratum: Validating genetic risk associations for ovarian cancer through the International Ovarian Cancer Association Consortium (British Journal of Cancer (2009) 100 (412-420) DOI: 10.1038/sj.bjc.6604820 www.bjcancer.com)

CL Pearce, AM Near, DJ Van Den Berg, SJ Ramus, A Gentry-Maharaj, U Menon, SA Gayther, AR Anderson, CK Edlund, AH Wu, X Chen, J Beesley, PM Webb, SK Holt, C Chen, JA Doherty, MA Rossing, AS Whittemore, V McGuire, RA DiCioccio, MT Goodman, G Lurie, ME Carney, LR Wilkens, RB Ness, KB Moysich, R Edwards, E Jennison, SK Kjaer, E Hogdall, CK Hogdall, EL Goode, TA Sellers, RA Vierkant, JM Cunningham, JM Schildkraut, A Berchuck, PG Moorman, ES Iversen, DW Cramer, KL Terry, AF Vitonis, L Titus-Ernstoff, H Song, PDP Pharoah, AB Spurdle, H Anton-Culver, A Ziogas, W Brewster, V Galitovskiy and G Chenevix-Trench, Australian Cancer Study (Ovarian Cancer) Australian Ovarian Cancer Study Group on behalf of the Ovarian Cancer Association Consortium