KRAS polymorphisms are associated with survival of CRC in Chinese population

Association of the rs8720 and rs12587 KRAS Gene Variants with Colorectal Cancer in a Mexican Population and Their Analysis In Silico

Colorectal cancer (CRC) is a major global health challenge and one of the top 10 cancers in Mexico. Lifestyle and genetic factors influence CRC development, prognosis, and therapeutic response; identifying risk factors, such as the genes involved, is critical to understanding its behavior, mechanisms, and prognosis. The association between KRAS gene variants (rs8720 and rs12587) and CRC in the Mexican population was analyzed. We performed in silico analysis and analyzed 310 healthy individuals and 385 CRC patients using TaqMan assays and real-time PCR. The CC and GG genotypes of rs8720 and rs12587 were identified as CRC risk factors (p < 0.05). The CC and TC genotypes of the rs8720 were associated with rectal cancer, age over 50 years, moderately differentiated histology, and advanced cancer stage. TG and GG genotypes of the rs12587 variant were a risk factor in the CRC group, in patients with stage I-II, males, and stage III-IV non-chemotherapy response. The TG haplotype is protected against CRC. The combined CCGG genotype was linked to CRC risk. In silico analysis revealed that the rs12587 and rs8720 variants could influence KRAS gene regulation via miRNAs. In conclusion, rs8720 and rs12587 variants of the KRAS gene were associated with CRC risk and could influence KRAS regulation via miRNAs.

Association analysis of miRNA-related genetic polymorphisms in miR-143/145 and KRAS with colorectal cancer susceptibility and survival

Background: There is accumulating evidence of aberrant expression of miR-143 and miR-145 and their target gene KRAS in colorectal cancer (CRC). We hypothesize that single nucleotide polymorphisms (SNPs) within or near mRNA–microRNA (miRNA) binding sites may affect miRNA/target gene interaction, resulting in differential mRNA/protein expression and promoting the development and progression of CRC. Methods: We conducted a case–control study of 507 patients with CRC recruited from a tertiary hospital and 497 population-based controls to assess the association of genetic polymorphisms in miR-143/145 and the KRAS 3′ untranslated region (3′UTR) with susceptibility to CRC and patients’ survival. In addition, genetic variations of genomic regions located from 500 bp upstream to 500 bp downstream of the miR-143/miR-145 gene and the 3′UTR of KRAS were selected for analysis using the Haploview and HaploReg software. Results: Using publicly available expression profiling data, we found that miR-143/145 and KRAS expression were all reduced in rectal cancer tissue compared with adjacent non-neoplastic large intestinal mucosa. The rs74693964 C/T variant located 65 bp downstream of miR-145 genomic regions was observed to be associated with susceptibility to CRC (adjusted odds ratio (OR): 2.414, 95% CI: 1.385–4.206). Cumulative effects of miR-143 and miR-145 on CRC risk were observed (P_trend=0.03). Patients having CRC carrying variant genotype TT of KRAS rs712 had poorer survival (log-rank P=0.044, adjusted hazard ratio (HR): 4.328, 95% CI: 1.236–15.147). Conclusions: Our results indicate that miRNA-related polymorphisms in miR-143/145 and KRAS are likely to be deleterious and represent potential biomarkers for susceptibility to CRC and patients’ survival.

MicroRNA-binding site polymorphisms and risk of colorectal cancer: A systematic review and meta-analysis

Genetic variations in miRNAs binding site might participate in cancer risk. This study aimed to systematically review the association between miRNA-binding site polymorphisms and colorectal cancer (CRC). Electronic literature search was carried out on PubMed, Web of Science (WOS), Scopus, and Embase. All types of observational studies till 30 November 2018 were included. Overall 85 studies (21 SNPs) from two systematic searches were included analysis. The results showed that in the Middle East population, the minor allele of rs731236 was associated with decreased risk of CRC (heterozygote model: 0.76 [0.61-0.95]). The minor allele of rs3025039 was related to increased risk of CRC in East Asian population (allelic model: 1.25 [1.01-1.54]). Results for rs3212986 were significant in overall and subgroup analysis (P < .05). For rs1801157 in subgroup analysis the association was significant in Asian populations (including allelic model: 2.28 [1.11-4.69]). For rs712, subgroup analysis revealed a significant (allelic model: 1.41 [1.23-1.61]) and borderline (allelic model: 0.92 [0.84-1.00]) association in Chinese and Czech populations, respectively. The minor allele of rs17281995 increased risk of CRC in different genetic models (P < .05). Finally, rs5275, rs4648298, and rs61764370 did not show significant associations. In conclusion, minor allele of rs3025039, rs3212986, and rs712 polymorphisms increases the risk of CRC in the East Asian population, and heterozygote model of rs731236 polymorphism shows protective effect in the Middle East population. In Europeans, the minor allele of rs17281995 may increase the risk of CRC, while rs712 may have a protective effect. Further analysis based on population stratifications should be considered in future studies.

KRAS SNPs are related to colorectal cancer susceptibility and survival in Chinese people

Aim: KRAS SNPs may increase KRAS transcription and KRAS levels. SNPs of KRAS 3'UTR can affect carcinoma risk and prognosis. Materials & methods: The rs8720 and rs7960917 in KRAS 3'UTR for colorectal carcinoma (CRC) risk and survival were investigated in a case-control study. Association between SNPs and CRC risk, survival analysis were analyzed by an unconditional logistic regression model, log-rank test, Kaplan-Meier estimation, Cox regression model and one-way analysis of variance. Results & conclusion: The genotype CT of rs8720 was significantly increased risk of CRC, decreased overall survival and event-free survival, and KRAS mRNA and protein expressions were significantly increased in individuals with rs8720 CT, TT genotype. rs8720 may be an important factor in CRC development and prognosis.

KRAS rs7973450 A>G increases neuroblastoma risk in Chinese children: a four-center case-control study

BACKGROUND

Neuroblastoma is one of the most common extracranial solid pediatric tumors. KRAS plays an important role in regulating cell proliferation, differentiation, and apoptosis. Single nucleotide polymorphisms (SNPs) in KRAS have been shown to modify susceptibility to multiple tumors, but no specific molecular epidemiology study was reported regarding neuroblastoma.

METHODS

We conducted a four-center case-control study to explore the association between KRAS gene polymorphisms (rs12587 G>T, rs7973450 A>G, rs7312175 G>A) and neuroblastoma susceptibility with 505 Chinese children and 1070 matched controls.

RESULTS

We found that rs7973450 A>G was associated with significantly increased neuroblastoma risk [GG vs. AA: adjusted odds ratio (OR)=4.26, 95% confidence interval (CI)=1.28-14.19, P=0.018; GG vs. AA/AG: adjusted OR=4.27, 95% CI=1.28-14.24, P=0.018]. The stratified analysis further demonstrated that rs7973450 GG genotype carriers had a higher risk to develop neuroblastoma in the subgroups of males, tumor originated from the adrenal gland and clinical stages III+IV.

CONCLUSIONS

Overall, our results suggested that rs7973450 A>G was associated with increased neuroblastoma risk.

Relationship between polymorphisms of the lipid metabolism-related gene PLA2G16 and risk of colorectal cancer in the Chinese population

This study aimed to investigate the relationship between polymorphisms in the lipid metabolism-related gene PLA2G16 encoding Group XVI phospholipase A2 and the risk of colorectal cancer (CRC) in the Chinese population. A total of 185 patients with CRC and 313 healthy controls were enrolled. Thirteen single nucleotide polymorphisms (SNPs) of PLA2G16 were genotyped with SNPscan™. Linkage disequilibrium and haplotypes were analysed using Haploview software. Multivariate logistic regression was used to determine the association between the various genotypes and CRC risk. We identified five PLA2G16 SNPs (rs11600655, rs3809072, rs3809073, rs640908 and rs66475048) that were associated with CRC risk after adjusting for age, sex and body mass index. Two haplotypes (CTC and GGA) of rs11600655, rs3809073 and rs3809072, were relevant to CRC risk. The rs11600655 polymorphism was also associated with lymph node metastasis and CRC staging, while rs3809073 and rs3809072 may affect transcriptional regulation of PLA2G16 by altering transcription factor binding. These findings suggest that PLA2G16 polymorphisms-especially CTC and GGA haplotypes-increase CRC susceptibility. Importantly, we showed that the rs11600655 CC, rs640908 CT and rs66475048 GA genotypes are independent risk factors for CRC in the Chinese population.

Single nucleotide polymorphisms and sporadic colorectal cancer susceptibility: a field synopsis and meta-analysis

Background

Although mounting non-hereditary colorectal cancer (NHCRC) associated single nucleotide polymorphisms (SNPs) have been observed, no field synopsis and meta-analysis has been conducted through systematically assessing cumulative evidence, during the past 5 years.

Methods

We retrieved the database via the PubMed, Web of Science and Embase gateways to identify publications concerning the associations between SNPs and risk of NHCRC, up to May 1st, 2017. To assess the finding credibility, cumulative evidence was graded based on the Venice criteria. Meta-analysis was also performed for three subgroups including ethnicity (Asian vs Caucasian), primary cancer site (colon vs rectum) and TNM stage (I II vs III IV). Then, we arranged those high quality SNPs into different regions according to their locations on genes to evaluate their functional roles on CRC development.

Results

5114 publications were collected and 1001 of them met our inclusion criteria, which totally included 1788 SNPs in 793 genes or distinct chromosomal loci. Totally, we performed 359 primary and subgroup meta-analyses for 160 SNPs in 96 distinct genes. By utilizing the Venice criteria, we identified 15 high quality SNPs with 25 high credibility significant associations. Furthermore, we artificially divided the high quality SNPs into different groups, based on their SNP loci (exon region, intron region, promoter region, downstream region, non-coding region and intergenic region).

Conclusion

We have identified 15 high quality SNPs which may act as promising genetic biomarkers for clinical NHCRC susceptibility screening and explored their functional roles on the NHCRC development based on their locations on genes.

Significant association between Let-7-KRAS rs712 G > T polymorphism and cancer risk in the Chinese population: a meta-analysis

Association between let-7-KRAS rs712 polymorphism and cancer risk was inconsistent. We therefore conducted this meta-analysis to clarify the association between let-7-KRAS rs712 polymorphism and cancer risk with STATA 14.0 software. A systemic literature search in online databases (PubMed, Embase, CNKI and Wanfang database) was preformed to obtain relevant articles. A total of 13 case-control studies involving 3,453 patients and 4,470 controls were identified up to May 16, 2015. The pooled results indicated that significantly increased risk were observed in Chinese population in T vs. G (OR = 1.21, 95% CI = 1.03–1.42) and TT vs. GG + GT genetic models (OR = 1.69, 95% CI = 1.17–2.42). Sensitivity analysis was conducted and the result without heterogeneity showed significant associations in all five genetic models. Subgroup analyses of cancer type indicated a similar result in digestive cancer (for T vs. G: OR = 1.41, 95% CI = 1.26–1.57; GT vs. GG: OR = 1.24, 95% CI = 1.07–1.43; TT vs. GG: OR = 2.53, 95% CI = 1.86–3.44; GT + TT vs. GG: OR = 1.36, 95% CI = 1.19–1.56; TT vs. GG + GT: OR = 2.35, 95% CI = 1.73–3.19). In summary, these evidences demonstrate that let-7-KRAS rs712 G > T polymorphism might be associated with digestive system cancer risk in the Chinese population.

KRAS Gene Polymorphisms and their Impact on Breast Cancer Risk in an Iranian Population

Single nucleotide polymorphisms (SNPs) in the let-7 miRNA binding site within the 3’ untranslated region (3’UTR) of KRAS appear related to the risk of cancer. The present case-control study was conducted with 244 BC patients and 204 healthy women to examine whether KRAS polymorphisms (rs61764370 T/G and rs712 G/T) are associated with breast cancer (BC) risk in an Iranian population. The polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) method was used for genotyping of KRAS SNPs. Our results showed that the rs61764370 TG genotype (OR= 3.73; 95% CI =1.38-10.08; P=0.007) as well as the G allele OR= 3.56; 95% CI =1.33-9.53; P=0.008, respectively) increased the risk of BC. However, the KRAS rs712 TT vs GG+GT genotype in a recessive model was associated with a reduced risk of BC (OR= 0.56; 95% CI =0.38-0.84; P=0.006). In addition, the rs712 T allele decreased the risk of BC compared with the G allele (OR=0.75, 95%CI=0.58-0.97, P=0.031). However, we found no relationship among KRAS SNPs and clinicopathological characteristics of BC patients (P>0.05). Taken together, the present study provided evidence of relationships between KRAS polymorphisms and BC risk in a southeast Iranian population. Additional studies using larger sample sizes and diverse ethnicities are now warranted.

Identification of Haplotype Tag Single-Nucleotide Polymorphisms within the PPAR Family Genes and Their Clinical Relevance in Patients with Major Trauma

Background: Peroxisome proliferator-activated receptors (PPARs) play important roles in the development of inflammatory diseases and sepsis. Recently, genetic variants of PPARs genes have been widely studied in some inflammatory diseases. However, the association between PPAR family of genes polymorphisms and sepsis risk in trauma patients was little known. Methods: SNPs were selected from the PPARs genes through constructing haplotype blocks and genotyped by the improved multiplex ligation detection reaction (iMLDR) method. The association between the selected SNPs and the risk of sepsis and multiple organ dysfunction (MOD) scores was evaluated in 734 trauma patients. In addition, tumor necrosis factor α (TNFα) production of peripheral blood leukocytes was also analyzed after lipopolysaccharide (LPS) stimulation. Results: Our results revealed that there were significant associations between the rs10865710 polymorphism and the risk of sepsis and MOD scores in Chinese Han trauma patients. Further, we found that the level of TNFα production was higher in patients with the rs10865710 G allele compared to those with the variant C allele. Conclusions: The rs10865710 polymorphism in the PPARγ gene might be used to assess the risk of sepsis and multiple organ dysfunction syndrome (MODS) in trauma patients.