International journal of molecular epidemiology and genetics最新文献

Telomere shortening is associated with colorectal carcinogenesis and recent studies have focused on its characteristics in both normal mucosa and tumor tissues. To clarify the role of telomeres in colorectal carcinogenesis, we analyzed telomere shortening in normal and tumor regions of 93 colorectal precursor lesions. Telomere length was examined in 61 tubular adenomas (TAs) and 32 serrated polyps (SPs), and PIK3CA expression, KRAS mutation, BRAF mutation, and MSI were also analyzed. Telomere length was similar in normal and tumor tissues of TAs and SPs. In normal tissues of TAs, telomere shortening was associated with PIK3CA amplification (81.3% vs. 18.8%, p < 0.001), whereas it was associated with BRAF mutation in normal tissues of SPs (66.7% vs. 23.1%, p = 0.060). According to the analysis on tumor tissues, KRAS and BRAF mutations were mutually exclusive in TAs and SPs (p < 0.001), and telomere shortening was associated with mitochondrial microsatellite instability (63.6% vs. 36.4%, p = 0.030). These data suggested a pivotal role of telomere shortening in normal colorectal tissue for proceeding to TAs or SPs along with PIK3CA amplification and BRAF mutation, respectively. Moreover, telomeres in TAs may collaborate with mitochondrial instability for disease progression.

[This corrects the article on p. 1 in vol. 8, PMID: 28337312.].

The aryl hydrocarbon receptor (AhR) is a transcription factor implicated in several pathways known to be relevant in lymphomagenesis. Aim of our study was to explore the link between AhR activation and risk of lymphoma subtypes. We used a Dual-Luciferase Assay^® and a luminometer to detect the activation of the luciferase gene, in HepG2 cells transfected with a specific reporter systems, by a 50 ml serum aliquot of cases of diffuse large B cell lymphoma (N = 108), follicular lymphoma (N = 85), chronic lymphocytic leukemia (N = 72), multiple myeloma (N = 80), and Hodgkin lymphoma (N = 94) and 357 controls who participated in the multicentre Italian study on gene-environment interactions in lymphoma etiology (ItGxE). Risk of each lymphoma subtype associated with AhR activation was calculated with polytomous logistic regression adjusting by age, gender, and study centre. The overall prevalence of AhR activation ranged 13.9-23.6% by subtype, and it varied by study area (8-39%). Risk associated with AhR activation was moderately elevated for follicular lymphoma (OR = 1.56, 95% CI 0.86, 2.80) and chronic lymphocytic leukemia (OR = 1.56, 95% CI 0.83, 2.96). Despite our inconclusive findings about the association with risk of lymphoma subtypes, we showed that the Dual-Luciferase Assay can be reliably and easily applied in population-based studies to detect AhR activation.

Gastric cancer (GC) is the 5th most prevalent cancer. The etiology of GC is still poorly understood. We performed a case-control study in a Chinese population to investigate the association of rs2243248 (-1098 G/T), rs2227284 (-33 C/T), rs2243250 (-589 T/C) and rs2070874 (-107 T/C) polymorphisms and haplotypes with the development of gastric cancer in a Chinese population. A total of 362 patients with gastric cancer and 384 controls were recruited between December 2013 and December 2015. Genotyping of rs2243248 (-1098 G/T), rs2227284 (-33 C/T), rs2243250 (-589 T/C) and rs2070874 (-107 T/C) was performed in a 384-well plate format on the sequenom MassARRAY platform, and analyzed by MALDI-TOF MS. The TC and CC genotypes of rs2243250 (-589 T/C) were associated with an increased risk of gastric cancer when compared with the TT genotype, with adjusted ORs (95% CI) of 1.52 (1.07-2.15) and 2.13 (1.30-3.51), respectively. The TTTT haplotype revealed a reduced risk of gastric cancer (OR=0.65, 95% CI=0.45-0.94). No linkage disequilibrium was found among IL-4 rs2243248, rs2227284, rs2243250 and rs2070874. In summary, our findings support a significant association of IL-4 rs2243250 polymorphism with the risk of gastric cancer in the Chinese population, and IL-4 haplotype contributes to the development of this disease.

Chronic hepatitis B is a global health problem, and is one of the leading causes of cirrhosis and hepatocellular carcinoma. Hepatitis B virus (HBV) genotyping helps in decision making for clinical management of HBV infection, and is important for epidemiological studies. The objectives of this study were to investigate the distribution of HBV genotypes circulating in the Philippines; molecularly characterize untypable genotype restriction patterns; and analyze the presence of surface gene variants. HBV genotypes were determined by restriction fragment length polymorphism (RFLP) and DNA sequencing. Three genotypes, HBV A (76%; 73/96), HBV B (10%; 10/96) and HBV C (14%; 13/96) were detected by RFLP. Out of the 96 isolates, 9% were untypable by RFLP analysis. DNA sequencing followed by phylogenetic analysis revealed that these isolates belonged to HBV genotypes A (67%; 6/9), B (11%; 1/9) and C (22%; 2/9). Out of the 9 isolates, 55% showed single or multiple variations which resulted to amino acid changes. Overall, the identification of untypable genotype can be resolved by sequence and phylogenetic analysis of the S gene and this approach can also be used to detect single or multiple variants. Our findings underscore the importance of accurate genotyping and detection of surface gene variants by DNA sequencing for optimal clinical management.

Background: A colorectal cancer may develop through a particular molecular genetic pathway, raising the question of whether the particular molecular changes are random, or are unique to the particular segment of colon. We wanted to determine whether molecular changes found within a colorectal cancer might also be detected in separate adenomas and polyps removed from the same area of colon at surgery. Microsatellite instability was chosen as a marker for a pathway of colon carcinogenesis.

Methods: We studied a total of 46 primary colorectal cancers with microsatellite instability and 77 synchronous adenomas and polyps. All tumors were evaluated for microsatellite instability, BRAF and KRAS mutations, and methylation using standard polymerase chain reaction based methods.

Results: Forty-nine benign tumors did not follow a pathway similar to that of their 31 synchronous primary cancers. For two distinct subsets of the microsatellite unstable colorectal cancers, those with acquired methylation and BRAF mutation, and those without methylation suggestive of an underlying germ line mutation, the molecular changes in the majority of their synchronous benign tumors were different from the colorectal cancer.

Conclusions: These differences suggest a stochastic process within the colon regarding the particular molecular carcinogenic pathways followed by the synchronous tumors, rather than a 'field defect' within the colon segments. Variability in molecular findings was present for colorectal cancers arising from acquired methylation, as well as those cancers suggestive of a germ line origin.

Toll-like receptors (TLRs) and the receptor for advanced glycation end products (AGER) are pattern recognition receptors that regulate intestinal inflammatory homeostasis. However, their relevance in colorectal cancer (CRC) prognosis is unclear. We investigated expression of TLRs, AGER, and interacting proteins in association with CRC mortality in a retrospective cohort study of 65 males diagnosed with primary resectable CRC between 2002 and 2009. Multiplex quantitative nuclease protection assay was used to quantify the expression of 19 genes in archived tissues of tumor and paired adjacent normal mucosa. We evaluated the association between log2 (tumor/normal) expression ratios for single and combined genes and all-cause mortality using multivariable Cox regression analysis. The false discovery rate adjusted q-value less than 0.10 indicated statistical significance for single gene. Five-year survival time was calculated from diagnosis of CRC to death, lost to follow-up, or December 31, 2014. Compared to paired normal mucosa, expression levels of AGER, IL1A, MYD88, and TLR5 were lower (q = 0.0002); while CXCL8 and S100P were higher (q = 0.0002) in tumor epithelia. Higher tumor expression of IL1A (HRadj = 0.68, 95% CI: 0.49-0.94), IL6 (HRadj = 0.70, 95% CI: 0.52-0.94), MyD88 (HRadj = 0.53, 95% CI: 0.30-0.93), and TLR5 (HRadj = 0.71, 95% CI: 0.52-0.98) was associated with higher mortality risk. There was a synergistic effect on lower five-year survival in lower co-expressers of IL-6 and MyD88 (P < 0.0001). Our findings suggest that a TLRs/MyD88-mediated inflammatory response may play a role in CRC prognosis. The role of pattern recognition receptor-mediated immunity in CRC mortality warrants further research.

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. miR-34 induces changes of its downstream genes, and plays a key role in altering the apoptotic cycle and pathways of downstream cells, and finally influences the development of cancer. We assessed the relationship of the pri-miR-34b/c rs4938723 polymorphism with hepatocellular carcinoma risk in a Chinese population. During the period of January 2014 and December 2015, a total of 164 HCC patients and 305 healthy controls were recruited from the Inner Mongolia People's Hospital. Genotyping of the pri-miR-34b/c rs4938723 was determined using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Using χ² test, we observed that HCC patients were likely to have a habit of alcohol consumption (χ² = 10.24, P = 0.001) and infect with HBV or HCV (χ² = 128.17, P < 0.001). In co-dominant model, the CC genotype of pri-miR-34b/c rs4938723 had a significant higher risk of HCC as compared with the TT genotype, and the corresponding adjusted OR (95% CI) was 4.14 (1.91-9.75). In dominant model, we observed that the TC+CC genotype were associated with an increased risk of HCC in comparison to the TT genotype (OR = 1.67, 95% CI = 1.17-2.55). In recessive model, the CC genotype was correlated with an elevated risk of HCC when compared with the TT+TC genotype (OR = 3.46, 95% CI = 1.62-8.54). The pri-miR-34b/c rs4938723 polymorphism was associated with a higher risk of HCC in the Chinese population examined. Further large-scale and multi-center studies are required to confirm these results.

Genetic variability in humans can explain many differences in disease risk factors. Polymorphism-related studies focus mainly on the single nucleotide polymorphisms (SNPs) of coding regions of the genes. SNPs on DNA binding motifs of the promoter region have been less explored. On a recent study of SNPs in patients with non-Hodgkin lymphomas we faced the problem of SNP selection from promoter regions and developed a practical methodology for clinical studies. The process consists in identifying SNPs in the coding and promoter regions of the antigen-processing system using the 'dbSNP' database. With the 'HapMap' program, we select SNPs with frequencies >20% in Caucasian populations. For coding regions, we sought biologically and clinically relevant SNPs described in the literature. For the promoter regions, we determined their chromosomal location on 'QiagenSABioscience' site database. The nucleotide sequence of ancestral and variant alleles is available in the 'dbSNP'. These sequences were used in 'Promoter TESS' to determine binding differences of transcription factors. Each sequence may have affinity to different TFs. Thus, SNP selection on the promoter regions was based in the differences on TF binding pattern between the old and the new allele. The potential clinical relevance of the new TFs was also evaluated before the final selection. With this approach, we found that almost half of the relevant SNP fall within the promoter region. In conclusion, we were able to develop a methodology of oriented selection of promoter regions of human genes, comparing the TF with affinity to the ancestral allele with the TF to a variant allele. We selected those SNPs that change the TF's affinity to a pattern with functional significance.

Cigarette smoking is the leading preventable cause of death worldwide. The aim of this study is to conduct a prospective and retrospective analysis of smoking behavior changes in the Lovelace Smokers Cohort (LSC) and the Pittsburgh Lung Screening Study cohort (PLuSS). Area under the curve (AUC) for risk models predicting relapse based on demographic, smoking, and relevant clinical variables was 0.93 and 0.79 in LSC and PLuSS, respectively. The models for making a quit attempt had limited prediction ability in both cohorts (AUC≤0.62). We identified an ethnic disparity in adverse smoking behavior change that Hispanic smokers were less likely to make a quit attempt and were more likely to relapse after a quit attempt compared to non-Hispanic Whites. SNPs at 15q25 and 11p14 loci were associated with risk for smoking relapse in the LSC. Rs6495308 at 15q25 has a large difference in minor allele frequency between non-Hispanic Whites and Hispanics (0.46 versus 0.23, P<0.0001) and was associated with risk for ever relapse at same magnitude between the two ethnic groups (OR=1.36, 95% CI=1.10 to 1.67 versus 1.59, 95% CI=1.00 to 2.53, P=0.81). In summary, the risk prediction model established in LSC and PLuSS provided an excellent to outstanding distinguishing for abstainers who will or will not relapse. The ethnic disparity in adverse smoking behavior between Hispanics and non-Hispanic Whites may be at least partially explained by the sequence variants at 15q25 locus that contains multiple nicotine acetylcholine receptors.