No abstract

Genome-wide association studies (GWASs) have identified multiple susceptibility loci of colorectal cancer (CRC), however, causative polymorphisms have not been fully elucidated. Long non-coding RNAs (lncRNAs) are a recently discovered class of non-protein coding RNAs that involved in a wide variety of biological processes. We hypothesized that single nucleotide polymorphisms (SNPs) in lncRNA may associate with the CRC risk by influencing lncRNA functions. To evaluate the effects of SNPs on CRC susceptibility in Chinese populations, we first screened out all potentially functional SNPs in exons of lncRNAs located in CRC susceptibility loci identified by GWAS. Eight SNPs were selected and genotyped in 875 CRC cases and 855 controls and replicated in an independent case-control study consisting of 768 CRC cases and 768 controls. Analyses showed that CG and GG genotypes of the rs2147578 were significantly associated with increased risk for CRC occurrence in both case-control studies [combined analysis OR = 1.29; 95% confidence interval (CI) = 1.11-1.51, P = 0.001] compared to the rs2147578 CC genotype. Bioinformatics analyses showed that rs2147578 is located in the transcript of lnc-LAMC2-1:1 and could influence the binding of lnc-LAMC2-1:1/miR-128-3p. Further luciferase reporter assays demonstrated that the construct with the risk rs2147578G allele had relatively high expression activity compared with that of the rs2147578C allele. Expression quantitative trait loci analyses also showed that rs2147578 is correlated with the expression of a well established oncogene LAMC2 (laminin subunit gamma 2). These findings indicated that rs2147578 in lnc-LAMC2-1:1 might be a genetic modifier for the development of CRC.

Genome-wide association studies have identified common variants associated with risk of esophageal squamous cell carcinoma (ESCC). However, these common variants cannot explain all heritability of ESCC. Here we report an exome-wide interrogation of 3,714 individuals with ESCC and 3,880 controls for low-frequency susceptibility loci, with two independent replication samples comprising 7,002 cases and 8,757 controls. We found six new susceptibility loci in CCHCR1, TCN2, TNXB, LTA, CYP26B1 and FASN (P = 7.77 × 10 to P = 1.49 × 10), and three low-frequency variants had relatively high effect size (odds ratio > 1.5). Individuals with the rs138478634-GA genotype had significantly lower levels of serum all-trans retinoic acid, an anticancer nutrient, than those with the rs138478634-GG genotype (P = 0.0004), most likely due to an enhanced capacity of variant CYP26B1 to catabolize this agent. These findings emphasize the important role of rare coding variants in the development of ESCC.

The role of Body Mass Index (BMI) for Breast Cancer (BC) remains to be great interest for a long time. However, the precise effect of nonlinear dose-response for BMI and BC risk is still unclear. We conducted a dose-response meta-analysis to quantitatively assess the effect of BMI on BC risk. Twelve prospective studies with 4,699 cases identified among 426,199 participants and 25 studies of 22,809 cases identified among 1,155,110 participants in premenopausal and postmenopausal groups, respectively, were included in this meta-analysis. Significant non-linear dose-response (P < 0.001) association was identified between BMI and BC risk in postmenopausal women. Individuals with BMI of 25, 30, and 35 kg/m2 yielded relative risks (RRs) of 1.02 [95% confidence interval (CI): 0.98–1.06], 1.12 (95% CI: 1.01–1.24), and 1.26 (95% CI: 1.07–1.50), respectively, when compared to the mean level of the normal BMI range. However, inverse result though not significant was observed in premenopausal women. In conclusion, the results of this meta-analysis highlighted that obesity contributed to increased BC risk in a nonlinear dose-response manner in postmenopausal women, and it is important to realize that body weight control may be a crucial process to reduce BC susceptibility.