The genetic susceptibility to colorectal cancer (CRC) has been estimated to be around 35% and yet high-penetrance germline mutations found so far explain less than 5% of all cases. Much of the remaining variations could be due to the co-inheritance of multiple low penetrant variants. The identification of all the susceptibility alleles could have public health relevance in the near future. To test the hypothesis that what are considered polymorphisms in human CRC genes could constitute low-risk alleles, we selected eight common SNPs for a pilot association study in 1785 cases and 1722 controls. One SNP, rs3219489:G>C (MUTYH Q324H) seemed to confer an increased risk of rectal cancer in homozygous status (OR=1.52; CI=1.06-2.17). When the analysis was restricted to our 'super-controls', healthy individuals with no family history for cancer, also rs1799977:A>G (MLH1 I219V) was associated with an increased risk in both colon and rectum patients with an odds ratio of 1.28 (CI=1.02-1.60) and 1.34 (CI=1.05-1.72), respectively (under the dominant model); while 2 SNPs, rs1800932:A>G (MSH6 P92P) and rs459552:T>A (APC D1822V) seemed to confer a protective effect. The latter, in particular showed an odds ratio of 0.76 (CI=0.60-0.97) among colon patients and 0.73 (CI=0.56-0.95) among rectal patients. In conclusion, our study suggests that common variants in human CRC genes could constitute low-risk alleles.
The extent of linkage disequilibrium (LD) was studied in two small food-gathering populations-Evenki and Saami-and two larger food-producing populations-Finns and Swedes-in northern Eurasia. In total, 50 single-nucleotide polymorphisms (SNPs) from five genes were genotyped using real-time pyrophosphate DNA sequencing, whereas 14 microsatellites were genotyped in two X-chromosomal regions. In addition, hypervariable region I of the mtDNA was sequenced to shed light on the demographic history of the populations. The SNP data, as well as the microsatellite data, reveal extensive levels of LD in Evenki and Saami when compared to Finns and Swedes. mtDNA-sequence variation is compatible with constant population size over time in Evenki and Saami but indicates population expansion in Finns and Swedes. Furthermore, the similarity between Finns and Swedes in SNP allele- and haplotype-frequency distributions indicate that these two populations may share a recent common origin. These findings suggest that populations such as the Evenki and the Saami, rather than the Finns, may be particularly suited for the initial coarse mapping of common complex diseases.
Rationale and design of the PREFERS (Preserved and Reduced Ejection Fraction Epidemiological Regional Study) Stockholm heart failure study: an epidemiological regional study in Stockholm county of 2.1 million inhabitants.
Heart failure (HF) with preserved (HFpEF) or reduced (HFrEF) ejection fraction is associated with poor prognosis and quality of life. While the incidence of HFrEF is declining and HF treatment is effective, HFpEF is increasing, with no established therapy. PREFERS Stockholm is an epidemiological study with the aim of improving clinical care and research in HF and to find new targets for drug treatment in HFpEF (https://internwebben.ki.se/sites/default/files/20150605_4d_research_appendix_final.pdf).
Patients with new-onset HF (n = 2000) will be characterized at baseline and after 1-year follow-up by standardized protocols for clinical evaluation, echocardiography, and ECG. In one subset undergoing elective coronary bypass surgery (n = 100) and classified according to LV function, myocardial biopsies will be collected during surgery, and cardiac magnetic resonance (CMR) imaging will be performed at baseline and after 1 year. Blood and tissue samples will be stored in a biobank. We will characterize and compare new-onset HFpEF and HFrEF patients regarding clinical findings and cardiac imaging, genomics, proteomics, and transcriptomics from blood and cardiac biopsies, and by established biomarkers of fibrosis, inflammation, haemodynamics, haemostasis, and thrombosis. The data will be explored by state-of-the-art bioinformatics methods to investigate gene expression patterns, sequence variation, DNA methylation, and post-translational modifications, and using systems biology approaches including pathway and network analysis.
In this epidemiological HF study with biopsy studies in a subset of patients, we aim to identify new biomarkers of disease progression and to find pathophysiological mechanisms to support explorations of new treatment regimens for HFpEF.
The arginine variant of the p53 codon 72 polymorphism as well as anogenital and epidermodysplasia verruciformis (EV) types of human papilloma virus (HPV) are suggested to confer increased risk for developing cutaneous squamous cell carcinoma (SCC). In this pilot study, we analysed the p53 codon 72 genotype distribution in 106 microdissected samples from normal and tumour tissues of 53 cases of cutaneous SCC and 96 controls from Sweden. Both normal and tumour samples from cases of SCC were screened for anogenital and EV HPV. The p53Arg allele was not associated with the development of cutaneous SCC. Anogenital HPV (44%) was more prevalent than EV HPV (12%). Data also indicate that anogenital HPV is more common in tumour samples, but HPV infection was not identified as a significant risk factor for developing SCC. The presence of anogenital HPV, but not EV HPV might be a risk factor for development of cutaneous SCC.