Association between colorectal cancer susceptibility loci and survival time after diagnosis with colorectal cancer

Colorectal Cancer Risk Loci: Prognostic Factors for Clinical Outcomes? A Systematic Review and Meta-Analysis

BACKGROUND

Several single nucleotide polymorphisms (SNPs) identified through genome-wide association studies (GWASs) on colorectal cancer (CRC) incidence are also shown as promising predictors of clinical outcomes in CRC patients. These genetic variants might help inform precision prognostic strategies by predicting disease progression, treatment response, and overall survival, thereby guiding more personalized treatment plans. However, conflicting evidence exists regarding their clinical relevance.

AIM

A systematic review and meta-analysis was performed to assess the potential of GWAS-identified SNPs in predicting CRC outcomes.

METHODS AND RESULTS

We conducted a comprehensive search of PubMed, Web of Science, Embase, and Cochrane databases up to 18 October 2024 for prospective studies that investigated the associations of CRC-related SNPs and polygenic risk scores (PRSs) built based on multiple SNPs with clinical outcomes. Quality of the included studies was assessed using the Newcastle-Ottawa Scale, and the heterogeneity was assessed by I2 index and Cochran's Q test. The final analysis included 22 studies with overall high quality and heterogeneity in several aspects (e.g., genetic models, ethnic background, and genetic signatures of CRC types). Among over 100 CRC risk-related loci, 12 SNPs were statistically associated with CRC clinical outcomes (mainly survival outcomes), which were replicated in multiple studies. Notably, rs9929218 and rs6983267, located in genes involved in processes of tumorigenesis, were linked to poor survival with hazard ratios (95% CIs) of 1.26 (1.12-1.42) under a recessive model and 1.33 (1.10-1.61) under an additive model, respectively, in the stratified analysis by genetic models. Besides, PRSs built based on survival-related SNPs were moderately associated with overall survival in CRC patients with hazard ratios exceeding 2.6 for each one-point increase in PRS.

CONCLUSIONS

Individual genetic variants and PRSs are predictive of CRC survival, and might serve as potential factors for risk stratification, which could help develop personalized treatment and surveillance strategies for CRC patients. However, the potential for false positives and the significant heterogeneity among studies that cannot be fully addressed in the current analysis due to limited data require a cautious interpretation of these findings. Large-scale studies are warranted to further explore and validate GWAS-identified SNPs for promising prognostic biomarkers in CRC patients while accounting for factors such as ethnic differences and tumor subtypes.

Colorectal Cancer Risk Prediction Using the rs4939827 Polymorphism of the SMAD7 Gene in the Romanian Population

Colorectal cancer (CRC) is globally recognized as a prevalent malignancy known for its significant mortality rate. Recent years have witnessed a rising incidence trend in colorectal cancer, emphasizing the necessity for early diagnosis. Our study focused on examining the impact of the SMAD7 gene variant rs4939827 on the risk of colorectal cancer occurrence. The composition of our study group included 340 individuals, comprising 170 CRC diagnosed patients and 170 healthy controls. We performed genotyping of all biological samples using the TaqMan assay on the ABI 7500 Real-Time PCR System (Applied Biosystems, Waltham, MA, USA). This investigation focused on the rs4939827 gene variant, assessing its association with CRC risk and clinicopathological characteristics. Genotyping results for the SMAD7 gene variant rs4939827 revealed a 42.6% prevalence of the C allele in CRC patients (p = 0.245) and a 22.8% prevalence of the T allele in control subjects (p = 0.109). This study concluded that there was an elevated risk of CRC in the dominant model for CC/CT+TT, with a p-value of 0.113 and an odds ratio (OR) of 2.781, within a 95% confidence interval (CI) of 0.998 to 3.456. The findings of our research indicate a correlation between variants of the SMAD7 gene and the likelihood of developing colorectal cancer in our study population. Consequently, these results could be instrumental in facilitating early diagnosis of colorectal cancer utilizing information on single-nucleotide polymorphism (SNP) and genetic susceptibility to the disease.

Relationship between 233 colorectal cancer risk loci and survival in 1926 patients with advanced disease

Background

Genome, transcriptome and methylome-wide association studies have identified single-nucleotide polymorphisms (SNPs) or genes at 258 loci associated with colorectal cancer (CRC) risk. We studied the relationship between these and patient outcome.

Methods

We studied 1926 unrelated patients with advanced CRC from COIN and COIN-B. Of 205 CRC-risk SNPs, 19 were directly genotyped and 162 were imputed, and of 53 risk genes, 52 were tested. An additive Cox model for overall survival was adjusted for known prognostic factors. For nominally significant SNPs or genes, we considered a recessive model with a Bonferroni corrected threshold of P = 2.1 × 10-4. We examined SNPs as expression quantitative trait loci (eQTL) and the relationship between gene expression in colorectal tumours and survival in 597 unrelated patients.

Results

Eleven SNPs or genes were nominally associated with survival under an additive model. Only rs117079142 mapping to UTP23 and EIF3H (Hazard Ratio [HR] = 2.79, 95% Confidence Intervals [CI] = 1.70-4.58, P = 4.7 × 10-5) and rs9924886 mapping to CDH1 and CDH3 (HR = 1.24, 95% CI = 1.12-1.38, P = 5.2 × 10-5) passed the multiple testing threshold under a recessive model. rs117079142 was an eQTL for UTP23 and rs9924886 for CDH1, CDH3 and ZFP90. Decreased CDH1 expression in CRCs was associated with worse survival (HR = 2.18, 95% CI = 1.3-3.5, P = 1.8 × 10-3).

Conclusion

rs117079142 and rs9924886 may represent potential prognostic biomarkers for CRC.

Association of several loci of SMAD7 with colorectal cancer: A meta-analysis based on case-control studies

BACKGROUND

Sma-and mad-related protein 7 (SMAD7) can affect tumor progression by closing transforming growth factor-beta intracellular signaling channels. Despite the extensive research on the correlation between SMAD7 polymorphisms and colorectal cancer (CRC), the conclusions of studies are still contradictory. We conducted a study focusing on the association of SMAD7 polymorphisms rs4939827, rs4464148, and rs12953717 with CRC.

METHODS

We searched through 5 databases for articles and used odd ratios (ORs) and 95% confidence intervals (CIs) to discuss the correlation of SMAD7 polymorphisms with CRC risk. The heterogeneity will be appraised by subgroup analysis and meta-regression. Contour-enhanced funnel plot, Begg test and Egger test were utilized to estimate publication bias, and the sensitivity analysis illustrates the reliability of the outcomes. We performed False-positive report probability and trial sequential analysis methods to verify results. We also used public databases for bioinformatics analysis.

RESULTS

We conclusively included 34 studies totaling 173251 subjects in this study. The minor allele (C) of rs4939827 is a protective factor of CRC (dominant, OR/[95% CI] = 0.89/[0.83-0.97]; recessive, OR/[95% CI] = 0.89/[0.83-0.96]; homozygous, OR/[95% CI] = 0.84/[0.76-0.93]; heterozygous, OR/[95% CI] = 0.91/[0.85-0.97]; additive, OR/[95% CI] = 0.91/[0.87-0.96]). the T allele of rs12953717 (recessive, OR/[95% CI] = 1.22/[1.15-1.28]; homozygous, OR/[95% CI] = 1.25/[1.13-1.38]; additive, OR/[95% CI] = 1.11/[1.05-1.17]) and the C allele of rs4464148 (heterozygous, OR/[95% CI] = 1.13/[1.04-1.24]) can enhance the risk of CRC.

CONCLUSION

Rs4939827 (T > C) can decrease the susceptibility to CRC. However, the rs4464148 (T > C) and rs12953717 (C > T) variants were connected with an enhanced risk of CRC.

F-box only protein 9 and its role in cancer

The F-box proteins (FBP), substrate recognition subunit of the SCF (Skp1-Cullin1-F-box protein complex) E3 ligase, play important roles in the ubiquitylation and subsequent degradation of the target proteins from several cellular processes. Disorders of F-box protein-mediated proteolysis lead to human malignancies. FBP plays an important role in many cellular processes, including cell proliferation, cell cycle, apoptosis, migration, invasion, and metastasis, suggesting that it can be associated with tumorigenesis, cancer development and progression. However, the expression and function of FBXO9 (F-box only protein 9) differ in various types of human cancer. Due to the ability to regulate the stability and activity of oncogenes and tumor-suppressor genes, and the physiological functions of many of the F-box proteins remain subtle, further genetic and mechanistic studies will elaborate and help define FBXO9's role. Targeting F-box protein or F-box protein signaling pathways could be an effective strategy for preventing or treating human cancer. This review is presented to summarize the part of FBXO9 in different types of human cancer and its regulation mechanism, and to pave the way to design FBXO9-targeting anticancer therapies.

Genome-wide association study identifies tumor anatomical site-specific risk variants for colorectal cancer survival

Identification of new genetic markers may improve the prediction of colorectal cancer prognosis. Our objective was to examine genome-wide associations of germline genetic variants with disease-specific survival in an analysis of 16,964 cases of colorectal cancer. We analyzed genotype and colorectal cancer-specific survival data from a consortium of 15 studies. Approximately 7.5 million SNPs were examined under the log-additive model using Cox proportional hazards models, adjusting for clinical factors and principal components. Additionally, we ran secondary analyses stratifying by tumor site and disease stage. We used a genome-wide p-value threshold of 5 × 10-8 to assess statistical significance. No variants were statistically significantly associated with disease-specific survival in the full case analysis or in the stage-stratified analyses. Three SNPs were statistically significantly associated with disease-specific survival for cases with tumors located in the distal colon (rs698022, HR = 1.48, CI 1.30-1.69, p = 8.47 × 10-9) and the proximal colon (rs189655236, HR = 2.14, 95% CI 1.65-2.77, p = 9.19 × 10-9 and rs144717887, HR = 2.01, 95% CI 1.57-2.58, p = 3.14 × 10-8), whereas no associations were detected for rectal tumors. Findings from this large genome-wide association study highlight the potential for anatomical-site-stratified genome-wide studies to identify germline genetic risk variants associated with colorectal cancer-specific survival. Larger sample sizes and further replication efforts are needed to more fully interpret these findings.

A genome-wide search for determinants of survival in 1926 patients with advanced colorectal cancer with follow-up in over 22,000 patients

BACKGROUND

While genome-wide association studies (GWAS) have identified germline variants influencing the risk of developing colorectal cancer (CRC), there has been limited examination of the possible role of inherited variation as a determinant of patient outcome.

PATIENTS AND METHODS

We performed a GWAS for overall survival (OS) in 1926 patients with advanced CRC from the COIN and COIN-B clinical trials. For single nucleotide polymorphisms (SNPs) showing an association with OS (P < 1.0 × 10-5), we conducted sensitivity analyses based on the time from diagnosis to death and sought independent replications in 5675 patients from the Study of Colorectal Cancer in Scotland (SOCCS) and 16,964 patients from the International Survival Analysis in Colorectal cancer Consortium (ISACC). We analysed the Human Protein Atlas to determine if ERBB4 expression was associated with survival in 438 patients with colon adenocarcinomas.

RESULTS

The most significant SNP associated with OS was rs79612564 in ERBB4 (hazard ratio [HR] = 1.24, 95% confidence interval [CI] = 1.16-1.32, P = 1.9 × 10-7). SNPs at 17 loci had suggestive associations for OS and all had similar effects on the time from diagnosis to death. No lead SNPs were independently replicated in the meta-analysis of all patients from SOCCS and ISACC. However, rs79612564 was significant in stage-IV patients from SOCCS (P = 2.1 × 10-2) but not ISACC (P = 0.89) and SOCCS combined with COIN and COIN-B attained genome-wide significance (P = 1.7 × 10-8). Patients with high ERBB4 expression in their colon adenocarcinomas had worse survival (HR = 1.50, 95% CI = 1.1-1.9, P = 4.6 × 10-2).

CONCLUSIONS

Genetic and expression data support a potential role for rs79612564 in the receptor tyrosine kinase ERBB4 as a predictive biomarker of survival.

Colorectal cancer risk variants rs10161980 and rs7495132 are associated with cancer survival outcome by a recessive mode of inheritance

Previous studies using additive genetic models failed to identify robust evidence of associations between colorectal cancer (CRC) risk variants and survival outcomes. However, additive models can be prone to false negative detection if the underlying inheritance mode is recessive. Here, we tested all currently known CRC-risk variants (n = 129) in a discovery analysis of 5675 patients from a Scottish cohort. Significant associations were then validated in 2474 CRC cases from UK Biobank. We found that the TT genotype of the intron variant rs7495132 in the CRTC3 gene was associated with clinically relevant poorer CRC-specific survival in both the discovery (hazard ratio [HR] = 1.97, 95% confidence interval [CI] = 1.41-2.74, P = 6.1 × 10-5 ) and validation analysis (HR = 1.69, 95% CI = 1.03-2.79, P = .038). In addition, the GG genotype of rs10161980 (intronic variant of AL139383.1 lncRNA) was associated with worse overall survival in the discovery cohort (HR = 1.24, 95% CI = 1.10-1.39, P = 3.4 × 10-4 ) and CRC-specific survival in the validation cohort (HR = 1.26, 95% CI = 1.01-1.56, P = .040). Our findings show that common genetic risk factors can also influence CRC survival outcome.

Association of Body Mass Index With Colorectal Cancer Risk by Genome-Wide Variants

BACKGROUND

Body mass index (BMI) is a complex phenotype that may interact with genetic variants to influence colorectal cancer risk.

METHODS

We tested multiplicative statistical interactions between BMI (per 5 kg/m2) and approximately 2.7 million single nucleotide polymorphisms with colorectal cancer risk among 14 059 colorectal cancer case (53.2% women) and 14 416 control (53.8% women) participants. All analyses were stratified by sex a priori. Statistical methods included 2-step (ie, Cocktail method) and single-step (ie, case-control logistic regression and a joint 2-degree of freedom test) procedures. All statistical tests were two-sided.

RESULTS

Each 5 kg/m2 increase in BMI was associated with higher risks of colorectal cancer, less so for women (odds ratio [OR] = 1.14, 95% confidence intervals [CI] = 1.11 to 1.18; P = 9.75 × 10-17) than for men (OR = 1.26, 95% CI = 1.20 to 1.32; P = 2.13 × 10-24). The 2-step Cocktail method identified an interaction for women, but not men, between BMI and a SMAD7 intronic variant at 18q21.1 (rs4939827; Pobserved = .0009; Pthreshold = .005). A joint 2-degree of freedom test was consistent with this finding for women (joint P = 2.43 × 10-10). Each 5 kg/m2 increase in BMI was more strongly associated with colorectal cancer risk for women with the rs4939827-CC genotype (OR = 1.24, 95% CI = 1.16 to 1.32; P = 2.60 × 10-10) than for women with the CT (OR = 1.14, 95% CI = 1.09 to 1.19; P = 1.04 × 10-8) or TT (OR = 1.07, 95% CI = 1.01 to 1.14; P = .02) genotypes.

CONCLUSION

These results provide novel insights on a potential mechanism through which a SMAD7 variant, previously identified as a susceptibility locus for colorectal cancer, and BMI may influence colorectal cancer risk for women.

Postmenopausal Hormone Therapy and Colorectal Cancer Risk by Molecularly Defined Subtypes and Tumor Location

BACKGROUND

Postmenopausal hormone therapy (HT) is associated with a decreased colorectal cancer (CRC) risk. As CRC is a heterogeneous disease, we evaluated whether the association of HT and CRC differs across etiologically relevant, molecularly defined tumor subtypes and tumor location.

METHODS

We pooled data on tumor subtypes (microsatellite instability status, CpG island methylator phenotype status, BRAF and KRAS mutations, pathway: adenoma-carcinoma, alternate, serrated), tumor location (proximal colon, distal colon, rectum), and HT use among 8220 postmenopausal women (3898 CRC cases and 4322 controls) from 8 observational studies. We used multinomial logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CIs) for the association of ever vs never HT use with each tumor subtype compared with controls. Models were adjusted for study, age, body mass index, smoking status, and CRC family history. All statistical tests were 2-sided.

RESULTS

Among postmenopausal women, ever HT use was associated with a 38% reduction in overall CRC risk (OR =0.62, 95% CI = 0.56 to 0.69). This association was similar according to microsatellite instability, CpG island methylator phenotype and BRAF or KRAS status. However, the association was attenuated for tumors arising through the serrated pathway (OR = 0.81, 95% CI = 0.66 to 1.01) compared with the adenoma-carcinoma pathway (OR = 0.63, 95% CI = 0.55 to 0.73; P het =.04) and alternate pathway (OR = 0.61, 95% CI = 0.51 to 0.72). Additionally, proximal colon tumors had a weaker association (OR = 0.71, 95% CI = 0.62 to 0.80) compared with rectal (OR = 0.54, 95% CI = 0.46 to 0.63) and distal colon (OR = 0.57, 95% CI = 0.49 to 0.66; P het =.01) tumors.

CONCLUSIONS

We observed a strong inverse association between HT use and overall CRC risk, which may predominantly reflect a benefit of HT use for tumors arising through the adenoma-carcinoma and alternate pathways as well as distal colon and rectal tumors.

Comprehensive analysis of colorectal cancer-risk loci and survival outcome: A prognostic role for CDH1 variants

PURPOSE

Genome-wide association studies have identified common single nucleotide polymorphisms (SNPs) at 83 loci associated with colorectal cancer (CRC) risk in European populations. Because germline variation can also influence patient outcome, we studied the relationship between these SNPs and CRC survivorship.

EXPERIMENTAL DESIGN

For the 83 risk loci, 10 lead SNPs were directly genotyped, 72 were imputed and 1 was not genotyped nor imputed, in 1948 unrelated patients with advanced CRC from the clinical trials COIN and COIN-B (oxaliplatin and fluoropyrimidine chemotherapy ± cetuximab). A Cox survival model was used for each variant, and variants classified by pathway, adjusting for known prognostic factors. We imposed a Bonferroni threshold of P = 6.6 × 10-4 for multiple testing. We carried out meta-analyses of published risk SNPs associated with survival.

RESULTS

Univariate analysis identified six SNPs associated with overall survival (OS) (P < 0.05); however, only rs9939049 in CDH1 remained significant beyond the Bonferroni threshold (Hazard Ratio [HR] 1.44, 95% Confidence Intervals [CI]: 1.21-1.71, P = 5.0 × 10-5). Fine mapping showed that rs12597188 was the most significant SNP at this locus and remained significant after adjustment for known prognostic factors beyond multiple testing thresholds (HR 1.23, 95% CI: 1.13-1.34, P = 1.9 × 10-6). rs12597188 was also associated with poor response to therapy (OR 0.61, 95% CI: 0.42-0.87, P = 6.6 × 10-3). No combinations of SNPs within pathways were more significantly associated with survival compared with single variants alone, and no other risk SNPs were associated with survival in meta-analyses.

CONCLUSIONS

The CRC susceptibility SNP rs9939049 in CDH1 influences patient survival and warrants further evaluation as a prognostic biomarker.

Single nucleotide polymorphisms associated with susceptibility for development of colorectal cancer: Case-control study in a Basque population

Given the significant population diversity in genetic variation, we aimed to investigate whether single nucleotide polymorphisms (SNPs) previously identified in studies of colorectal cancer (CRC) susceptibility were also relevant to the population of the Basque Country (North of Spain). We genotyped 230 CRC cases and 230 healthy controls for 48 previously reported CRC-susceptibility SNPs. Only the rs6687758 in DUPS10 exhibited a statistically significant association with CRC risk based on the crude analysis. The rs6687758 AG genotype conferred about 2.13-fold increased risk for CRC compared to the AA genotype. Moreover, we found significant associations in cases between smoking status, physical activity, and the rs6687758 SNP. The results of a Genetic Risk Score (GRS) showed that the risk alleles were more frequent in cases than controls and the score was associated with CRC in crude analysis. In conclusion, we have confirmed a CRC susceptibility locus and the existence of associations between modifiable factors and the rs6687758 SNP; moreover, the GRS was associated with CRC. However, further experimental validations are needed to establish the role of this SNP, the function of the gene identified, as well as the contribution of the interaction between environmental factors and this locusto the risk of CRC.

Effects of common genetic variants associated with colorectal cancer risk on survival outcomes after diagnosis: A large population-based cohort study

Genome-wide association studies have thus far identified 130 genetic variants linked to colorectal cancer (CRC) risk (r2  < 0.2). Given their implication in disease causation, and thus plausible biologically effects on cancer-relevant biological pathways, we investigated whether these variants are associated with CRC prognosis and also whether they might provide predictive value for survival outcome. We conducted the analysis in a well-characterized population-based study of 5,675 patients after CRC diagnosis in Scotland. None of the genetic risk variants were associated with either overall survival (OS) or CRC-specific survival. Next, we combined the variants in a polygenic risk score, but again we observed no association between survival outcome and overall genetic susceptibility to CRC risk-as defined by common genetic variants (OS: hazard ratio = 1.00, 95% confidence interval = 0.96-1.05). Furthermore, we found no incremental increase in the discriminative performance when adding these genetic variants to the baseline CRC-survival predictive model of age, sex and stage at diagnosis. Given that our study is well-powered (>0.88) to detect effects on survival for 74% of the variants, we conclude that effects of common variants associated with CRC risk which have been identified to date are unlikely to have clinically relevant effect on survival outcomes for patients diagnosed with CRC.

Smad7 and Colorectal Carcinogenesis: A Double-Edged Sword

Colorectal carcinogenesis is a complex process in which many immune and non-immune cells and a huge number of mediators are involved. Among these latter factors, Smad7, an inhibitor of the transforming growth factor (TGF)-β1 signaling that has been involved in the amplification of the inflammatory process sustaining chronic intestinal inflammation, is supposed to make a valid contribution to the growth and survival of colorectal cancer (CRC) cells. Smad7 is over-expressed by tumoral cells in both sporadic CRC and colitis-associated CRC, where it sustains neoplastic processes through activation of either TGFβ-dependent or non-dependent pathways. Consistently, genome-wide association studies have identified single nucleotide polymorphisms of the Smad7 gene associated with CRC and shown that either amplification or deletion of the Smad7 gene associates with a poor prognosis or better outcome, respectively. On the other hand, there is evidence that over-expression of Smad7 in immune cells infiltrating the inflamed gut of patients with inflammatory bowel disease can elicit anti-tumor responses, with the down-stream effect of attenuating CRC cell growth. Taken together, these observations suggest a double role of Smad7 in colorectal carcinogenesis, which probably depends on the cell subset and the biological context analyzed. In this review, we summarize the available evidences about the role of Smad7 in both sporadic and colitis-associated CRC.

Association between EN1 rs4144782 and susceptibility of knee osteoarthritis: A case-control study

Osteoarthritis (OA) is a complex disease that affects the whole joint, resulting from the combined influence of biomechanical factors and genetic factors. The heritable component for primary OA accounts for about 60% of variation in population liability to the disease. So far, genome-wide association studies (GWAS) and candidate gene studies have established many OA-related loci. However, these findings account for only a rather small fraction of the genetic component. To further reveal the genetic architecture of OA, we conducted this case-control study to explore the association of locus EN1 rs4144782 and knee OA susceptibility in a Chinese population. EN1 rs4144782 was significantly associated with increased risk of knee OA (OR=1.26; 95% CI: 1.05-1.50, P value=0.012). In dominant model, compared with carriers of GG genotype, those with AG or AA genotype have an 1.44-fold increased risk of OA (OR: 1.44; 95% CI: 1.10-1.88; P value=0.008). Subgroup analyses didn't change the results materially. This should be the first association study of EN1 locus on risk of OA, and our finding suggested that the EN1 rs4144782 might contribute to the susceptibility of knee OA.

A comprehensive meta-analysis of genetic associations between five key SNPs and colorectal cancer risk

Genome-wide association studies (GWAS) on colorectal cancer (CRC) have identified dozens of single nucleotide polymorphisms (SNPs) in more than 19 independent loci associated with CRC. Due to the heterogeneity of the studied subjects and the contrary results, it is challenging to verify the certainty of the association between these loci and CRC.We conducted a critical review of the published studies of SNPs associated with CRC. Five most frequently reported SNPs, which are rs6983267/8q24.21, rs4939827/18q21.1, rs10795668/10p14, rs4444235/14q22.2 and rs4779584/ 15q13.3, were selected for the current study from the qualified studies. Then meta-analyses based on larger sample sizes with average of 33,000 CRC cases and 34,000 controls were performed to assess the association between SNPs and CRC risk. Heterogeneity among studies and publication bias were assessed by the χ2-based Q statistic test Begg's funnel plot or Egger's test, respectively.Our meta-analysis confirmed significant associations of the five SNPs with CRC risk under different genetic models. Two risk variants at rs6983267 {Odds Ratio (OR) 1.388, 95% Confidence Interval (CI) 1.180-1.8633} and rs10795668 (OR 1.323, 95% CI 1.062-1.648) had the highest ORs in homogeneous model. While ORs of the other three variants at rs4939827 {OR 1.298, 95% CI 1.135-1.483}, rs4779584 (OR 1.261, 95% CI 1.146-1.386) and rs4444235 (OR 1.160, 95% CI 1.106-1.216) were also statistically significant. Sensitivity analyses and publication bias assessment indicated the robust stability and reliability of the results.

SMAD7 polymorphisms and colorectal cancer risk: a meta-analysis of case-control studies

Mothers against decapentaplegic homolog 7 (SMAD7) inhibits the transforming growth factor-β (TGF-β) signaling pathway, which regulates carcinogenesis and cancer progression. A number of studies have reported that SMAD7 polymorphisms (rs4464148, rs4939827, and rs12953717) are associated with colorectal cancer (CRC) risk, but the results from these studies remain conflicting. To determine a more precise estimation of the relationship between SMAD7 and CRC, we undertook a large-scale meta-analysis of 63 studies, which included a total of 187,181 subjects (86,585 cases and 100,596 controls). The results of our meta-analysis revealed that the C allele of rs4464148 [CC vs. TT+TC, odds ratio (OR) =1.23, 95% confidence interval (CI): 1.14–1.33, P < 0.01], the T allele of rs4939827 [TT vs. CC+TC, odds ratio OR=1.15, 95%CI:1.07–1.22, P < 0.01] and the T allele of rs12953717 [TT vs. CC+TC, OR =1.22, 95%CI:1.16–1.29, P < 0.01] were all associated with the increased CRC risk. Subgroup analysis according to ethnicity showed rs4464148 and rs12953717 were associated with the risk of CRC in both Caucasians and Asians, whereas rs4939827 was a risk polymorphism for CRC specifically in Caucasians. In summary, this large-scale meta-analysis indicated that SMAD7 polymorphisms (rs4464148, rs4939827, and rs12953717) correlate with CRC.

Evaluation of genetic variants in association with colorectal cancer risk and survival in Asians

Genome-wide association studies (GWAS) have identified over 40 genetic loci associated with colorectal cancer (CRC) risk. The association of single nucleotide polymorphisms (SNPs) at these loci with CRC risk and survival has not been adequately evaluated in East Asians. GWAS-identified CRC risk variants were used to construct weighted genetic risk scores (GRSs). We evaluated these GRSs in association with CRC risk in 3,303 CRC cases and 3,553 controls using logistic regression models. Associations with overall and CRC-specific survival were assessed in 731 CRC patients using Cox regression models. The association between the GRSs (overall and Asian-specific) and CRC risk was approximately twofold (highest vs. lowest quintile), and the shape of the dose-response was linear (ptrend  = 1.24 × 10-13 and 3.02 × 10-14 for overall GRS and Asian-specific GRS, respectively). The association of the GRS with CRC risk was stronger among those with a family history of CRC (pinteraction  = 0.007). Asian-specific GRS using previously reported survival SNPs increased risk for mortality and the shape of the dose-response was linear for CRC-specific and all-cause mortality (ptrend  = 0.01 and 0.006, respectively). Furthermore, the minor alleles of rs6983267 and rs1957636 were associated with worse CRC-specific and overall survival. We show that GRSs constructed using GWAS-identified common variants are strongly associated with CRC risk in Asians. We confirm previous findings for the possible association between some SNPs with survival, and provide evidence for two additional CRC risk variants that may be related to CRC survival.

SMAD7 rs4939827 variant contributes to colorectal cancer risk in Chinese population

A genome-wide association study identified a common genetic variant rs4939827 at 18q21 in SMAD7 to be related with colorectal cancer (CRC) risk with OR=1.2 and P =7.80E-28. Until recently, several meta-analysis studies have been conducted, and reported significant association between rs4939827 and CRC risk. However none of these studies evaluated the potential association between rs4939827 and CRC risk in Chinese population. In this study, we evaluated this association by a meta-analysis using 12077 samples including 5816 CRC cases and 6261 controls. In the end, we identified the T allele of rs4939827 to be significantly related with an increase CRC risk (P=2.22E-05, OR=1.14, 95% CI 1.07-1.21) in Chinese population.

Relationship of prediagnostic body mass index with survival after colorectal cancer: Stage-specific associations

Higher body mass index (BMI) is a well-established risk factor for colorectal cancer (CRC), but is inconsistently associated with CRC survival. In 6 prospective studies participating in the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO), 2,249 non-Hispanic white CRC cases were followed for a median 4.5 years after diagnosis, during which 777 died, 554 from CRC-related causes. Associations between prediagnosis BMI and survival (overall and CRC-specific) were evaluated using Cox regression models adjusted for age at diagnosis, sex, study and smoking status (current/former/never). The association between BMI category and CRC survival varied by cancer stage at diagnosis (I-IV) for both all-cause (p-interaction = 0.03) and CRC-specific mortality (p-interaction = 0.04). Compared to normal BMI (18.5-24.9 kg/m(2) ), overweight (BMI 25.0-29.9) was associated with increased mortality among those with Stage I disease, and decreased mortality among those with Stages II-IV disease. Similarly, obesity (BMI ≥30) was associated with increased mortality among those with Stages I-II disease, and decreased mortality among those with Stages III-IV disease. These results suggest the relationship between BMI and survival after CRC diagnosis differs by stage at diagnosis, and may emphasize the importance of adequate metabolic reserves for colorectal cancer survival in patients with late-stage disease.

Are SMAD7 rs4939827 and CHI3L1 rs4950928 polymorphisms associated with colorectal cancer in Egyptian patients?

A wide variety of genes have been associated with colorectal cancer (CRC) development and progression. The SMAD7 gene encodes an intracellular protein, which inhibits the transforming growth factor beta (TGF-β) signaling pathway, thereby having a key role in the control of neoplastic processes in various organs. The CHI3L1 gene encodes glycoprotein YKL-40, which plays a role in cell proliferation, anti-apoptosis, and angiogenesis. The present study aimed to evaluate the association of single nucleotide polymorphisms (SNPs) SMAD7 rs4939827 and CHI3L1 rs4950928, as well as circulating TGFβ-1 and YKL-40 levels with CRC in an Egyptian population of 77 CRC patients and 36 healthy controls. Polymorphisms in the SMAD7 rs4939827 and the CHI3L1 rs4950928 genes were determined using the real-time polymerase chain reaction (RT-PCR). Both the SMAD7 rs4939827 TT genotype and the CHI3L1 rs4950928 C allele were associated with the rectal but not the colon cancer. In addition, the C allele of both SMAD7 rs4939827 and CHI3L1 rs4950928 was associated with increased serum levels of TGF-β1 and YKL-40, respectively. In conclusion, our data suggest that SMAD7 rs4939827 and CHI3L1 rs4950928 SNPs have no significant association with CRC. A significant association of SNP in SMAD7 rs4939827 and CHI3L1 rs4950928 was revealed between the rectal cancer and colon cancer patients.

Germline determinants of clinical outcome of cutaneous melanoma

Cutaneous melanoma (CM) is the most lethal form of skin cancer. Despite the constant increase in melanoma incidence, which is in part due to incremental advances in early diagnostic modalities, mortality rates have not improved over the last decade and for advanced stages remain steadily high. While conventional prognostic biomarkers currently in use find significant utility for predicting overall general survival probabilities, they are not sensitive enough for a more personalized clinical assessment on an individual level. In recent years, the advent of genomic technologies has brought the promise of identification of germline DNA alterations that may associate with CM outcomes and hence represent novel biomarkers for clinical utilization. This review attempts to summarize the current state of knowledge of germline genetic factors studied for their impact on melanoma clinical outcomes. We also discuss ongoing problems and hurdles in validating such surrogates, and we also project future directions in discovery of more powerful germline genetic factors with clinical utility in melanoma prognostication.

Common genetic variation and survival after colorectal cancer diagnosis: a genome-wide analysis

Genome-wide association studies have identified several germline single nucleotide polymorphisms (SNPs) significantly associated with colorectal cancer (CRC) incidence. Common germline genetic variation may also be related to CRC survival. We used a discovery-based approach to identify SNPs related to survival outcomes after CRC diagnosis. Genome-wide genotyping arrays were conducted for 3494 individuals with invasive CRC enrolled in six prospective cohort studies (median study-specific follow-up = 4.2-8.1 years). In pooled analyses, we used Cox regression to assess SNP-specific associations with CRC-specific and overall survival, with additional analyses stratified by stage at diagnosis. Top findings were followed-up in independent studies. A P value threshold of P < 5×10(-8) in analyses combining discovery and follow-up studies was required for genome-wide significance. Among individuals with distant-metastatic CRC, several SNPs at 6p12.1, nearest the ELOVL5 gene, were statistically significantly associated with poorer survival, with the strongest associations noted for rs209489 [hazard ratio (HR) = 1.8, P = 7.6×10(-10) and HR = 1.8, P = 3.7×10(-9) for CRC-specific and overall survival, respectively). No SNPs were statistically significantly associated with survival among all cases combined or in cases without distant-metastases. SNPs in 6p12.1/ELOVL5 were associated with survival outcomes in individuals with distant-metastatic CRC, and merit further follow-up for functional significance. Findings from this genome-wide association study highlight the potential importance of genetic variation in CRC prognosis and provide clues to genomic regions of potential interest.

Molecular pathological epidemiology gives clues to paradoxical findings

A number of epidemiologic studies have described what appear to be paradoxical associations, where an incongruous relationship is observed between a certain well-established risk factor for disease incidence and favorable clinical outcome among patients with that disease. For example, the "obesity paradox" represents the association between obesity and better survival among patients with a certain disease such as coronary heart disease. Paradoxical observations cause vexing clinical and public health problems as they raise questions on causal relationships and hinder the development of effective interventions. Compelling evidence indicates that pathogenic processes encompass molecular alterations within cells and the microenvironment, influenced by various exogenous and endogenous exposures, and that interpersonal heterogeneity in molecular pathology and pathophysiology exists among patients with any given disease. In this article, we introduce methods of the emerging integrative interdisciplinary field of molecular pathological epidemiology (MPE), which is founded on the unique disease principle and disease continuum theory. We analyze and decipher apparent paradoxical findings, utilizing the MPE approach and available literature data on tumor somatic genetic and epigenetic characteristics. Through our analyses in colorectal cancer, renal cell carcinoma, and glioblastoma (malignant brain tumor), we can readily explain paradoxical associations between disease risk factors and better prognosis among disease patients. The MPE paradigm and approach can be applied to not only neoplasms but also various non-neoplastic diseases where there exists indisputable ubiquitous heterogeneity of pathogenesis and molecular pathology. The MPE paradigm including consideration of disease heterogeneity plays an essential role in advancements of precision medicine and public health.

Analyses of 7,635 Patients with Colorectal Cancer Using Independent Training and Validation Cohorts Show That rs9929218 in CDH1 Is a Prognostic Marker of Survival

PURPOSE

Genome-wide association studies have identified numerous loci associated with colorectal cancer risk. Several of these have also been associated with patient survival, although none have been validated. Here, we used large independent training and validation cohorts to identify robust prognostic biomarkers for colorectal cancer.

EXPERIMENTAL DESIGN

In our training phase, we analyzed 20 colorectal cancer-risk SNPs from 14 genome-wide associated loci, for their effects on survival in 2,083 patients with advanced colorectal cancer. A Cox survival model was used, stratified for treatment, adjusted for known prognostic factors, and corrected for multiple testing. Three SNPs were subsequently analyzed in an independent validation cohort of 5,552 colorectal cancer patients. A validated SNP was analyzed by disease stage and response to treatment.

RESULTS

Three variants associated with survival in the training phase; however, only rs9929218 at 16q22 (intron 2 of CDH1, encoding E-cadherin) was significant in the validation phase. Patients homozygous for the minor allele (AA genotype) had worse survival (training phase HR, 1.43; 95% confidence intervals; CI, 1.20-1.71, P = 5.8 × 10(-5); validation phase HR, 1.18; 95% CI, 1.01-1.37, P = 3.2 × 10(-2); combined HR, 1.28; 95% CI, 1.14-1.43, P = 2.2 × 10(-5)). This effect was independent of known prognostic factors, and was significant amongst patients with stage IV disease (P = 2.7 × 10(-5)). rs9929218 was also associated with poor response to chemotherapy (P = 3.9 × 10(-4)).

CONCLUSIONS

We demonstrate the potential of common inherited genetic variants to inform patient outcome and show that rs9929218 identifies approximately 8% of colorectal cancer patients with poor prognosis. rs9929218 may affect CDH1 expression and E-cadherin plays a role in epithelial-to-mesenchymal transition providing a mechanism underlying its prognostic potential. Clin Cancer Res; 21(15); 3453-61. ©2015 AACR.

Identification of a common variant with potential pleiotropic effect on risk of inflammatory bowel disease and colorectal cancer

Although genome-wide association studies (GWAS) have separately identified many genetic susceptibility loci for ulcerative colitis (UC), Crohn's disease (CD) and colorectal cancer (CRC), there has been no large-scale examination for pleiotropy, or shared genetic susceptibility, for these conditions. We used logistic regression modeling to examine the associations of 181 UC and CD susceptibility variants previously identified by GWAS with risk of CRC using data from the Genetics and Epidemiology of Colorectal Cancer Consortium and the Colon Cancer Family Registry. We also examined associations of significant variants with clinical and molecular characteristics in a subset of the studies. Among 11794 CRC cases and 14190 controls, rs11676348, the susceptibility single nucleotide polymorphism (SNP) for UC, was significantly associated with reduced risk of CRC (P = 7E-05). The multivariate-adjusted odds ratio of CRC with each copy of the T allele was 0.93 (95% CI 0.89-0.96). The association of the SNP with risk of CRC differed according to mucinous histological features (P heterogeneity = 0.008). In addition, the (T) allele was associated with lower risk of tumors with Crohn's-like reaction but not tumors without such immune infiltrate (P heterogeneity = 0.02) and microsatellite instability-high (MSI-high) but not microsatellite stable or MSI-low tumors (P heterogeneity = 0.03). The minor allele (T) in SNP rs11676348, located downstream from CXCR2 that has been implicated in CRC progression, is associated with a lower risk of CRC, particularly tumors with a mucinous component, Crohn's-like reaction and MSI-high. Our findings offer the promise of risk stratification of inflammatory bowel disease patients for complications such as CRC.

A subset of genetic susceptibility variants for colorectal cancer also has prognostic value

We investigated the possible influence of 86 single-nucleotide polymorphisms (SNPs), known to associate with the risk of colorectal cancer (CRC), on overall survival and time to recurrence (TTR) in 733 Italian CRC patients followed up for up to 84 months after surgery. In the Cox multivariate analysis, adjusted for gender, age, pathological stage and adjuvant chemotherapy (yes/no), the risk of death significantly increased by rare allele count (P<0.05) for rs1801133 (MTHFR), rs4939827 (SMAD7), rs2306283 (SLCO1B1) and rs12898159 (BMP4), whereas for rs736775 (GPX3) the opposite was observed. Two additional SNPs associated with TTR, namely rs16892766 (downstream of EIF3H) and rs10749971 (COLCA2). Our findings show that some genetic variants previously found to associate with CRC risk are also associated with survival after treatment. The identification of alleles defining subgroups of patients with worse clinical outcome may have application in developing pharmacogenetic strategies aimed at personalizing CRC treatment.

Association between GWAS-identified genetic variations and disease prognosis for patients with colorectal cancer

Genome-wide association studies (GWASs) have already identified at least 22 common susceptibility loci associated with an increased risk of colorectal cancer (CRC). This study examined the relationship between these single nucleotide polymorphisms (SNPs) and the clinical outcomes of patients with colorectal cancer. Seven hundred seventy-six patients with surgically resected colorectal adenocarcinoma were enrolled in the present study. Twenty-two of the GWAS-identified SNPs were genotyped using a Sequenom MassARRAY. Among the 22 SNPs, two (rs1321311G>T in CDKN1A and rs10411210C>T in RHPN2) were significantly associated with the survival outcomes of CRC in a multivariate survival analysis. In a recessive model, the rs1321311 TT genotype (vs. GG + GT) and rs10411210 TT genotype (vs. CC + CT) were associated with a worse prognosis for disease-free survival (adjusted HR = 1.90; 95% confidence interval = 1.00-3.60; P = 0.050, adjusted HR = 1.94; 95% confidence interval = 1.05-3.57; P = 0.034, respectively) and overall survival (adjusted HR = 2.05; 95% confidence interval = 1.00-4.20; P = 0.049, adjusted HR = 2.06; 95% confidence interval = 1.05-4.05; P = 0.036, respectively). None of the other SNPs was significantly associated with any clinicopathologic features or survival. The present results suggest that the genetic variants of the CDKN1A (rs1321311) and RHPN2 (rs10411210) genes can be used as prognostic biomarkers for patients with surgically resected colorectal cancer.

A retrospective observational study of the relationship between single nucleotide polymorphisms associated with the risk of developing colorectal cancer and survival

BACKGROUND

There is variability in clinical outcome for patients with apparently the same stage colorectal cancer (CRC). Single nucleotide polymorphisms (SNPs) mapping to chromosomes 1q41, 3q26.2, 6p21, 8q23.3, 8q24.21, 10p14, 11q13, 11q23.1, 12q13.13, 14q22, 14q22.2, 15q13.3, 16q22.1, 18q21.1, 19q13.11, 20p12, 20p12.3, 20q13.33 and Xp22 have robustly been shown to be associated with the risk of developing CRC. Since germline variation can also influence patient outcome the relationship between these SNPs and patient survivorship from CRC was examined.

METHODS

All enrolled into the National Study of Colorectal Cancer Genetics (NSCCG) were genotyped for 1q41, 3q26.2, 6p21, 8q23.3, 8q24.21, 10p14, 11q13, 11q23.1, 12q13.13, 14q22, 14q22.2, 15q13.3, 16q22.1, 18q21.1, 19q13.11, 20p12, 20p12.3, 20q13.33 and xp22 SNPs. Linking this information to the National Cancer Data Repository allowed patient genotype to be related to survival.

RESULTS

The linked dataset consisted of 4,327 individuals. 14q22.22 genotype defined by the SNP rs4444235 showed a significant association with overall survival. Specifically, the C allele was associated with poorer observed survival (per allele hazard ratio 1.13, 95% confidence interval 1.05-1.22, P = 0.0015).

CONCLUSION

The CRC susceptibility SNP rs4444235 also appears to exert an influence in modulating patient survival and warrants further evaluation as a potential prognostic marker.

Variants identified by hepatocellular carcinoma and chronic hepatitis B virus infection susceptibility GWAS associated with survival in HBV-related hepatocellular carcinoma

Recent genome-wide association studies (GWAS) have identified several common susceptibility loci associated with the risk of hepatocellular carcinoma (HCC) or chronic hepatitis B infection (CHB). However, the relationship between these genetic variants and survival of patients with hepatitis B virus (HBV)-related HCC is still unknown. In this study, 22 single nucleotide polymorphisms (SNPs) were genotyped among 330 HBV-related HCC patients using the MassARRAY system from Sequenom. Cox proportional hazards regression was used to examine the effects of genotype on survival time under an additive model with age, sex, smoking status and clinical stage as covariates. We identified four SNPs on 6p21 (rs1419881 T>C, rs7453920 G>A,rs3997872 G>A and rs7768538 T>C), and two SNPs on 8p12 (rs2275959 C>T and rs7821974 C>T) significantly associated with survival time of HBV-related HCC patients. Our results suggest that HCC or CHB susceptibility loci might also affect the prognosis of patients with HBV-related HCC.

Germline variation in colorectal risk Loci does not influence treatment effect or survival in metastatic colorectal cancer

BACKGROUND

Colorectal cancer (CRC) risk is partly conferred by common, low-penetrance single nucleotide polymorphisms (SNPs). We hypothesized that these SNPs are associated with outcomes in metastatic CRC.

METHODS

Six candidate SNPs from 8q24, 10p14, 15q13, 18q21 were investigated for their association with response rate (RR), time to progression (TTP) and overall survival (OS) among 524 patients treated on a phase III clinical trial of first-line chemotherapy for metastatic CRC.

RESULTS

rs10795668 was weakly associated with TTP (p = 0.02), but not RR or OS. No other SNPs carried statistically significant HRs for any of the primary outcomes (RR, TTP or OS).

CONCLUSION

Common low-penetrance CRC risk SNPs were not associated with outcomes among patients with metastatic CRC.

Genome-wide association study identifies a new SMAD7 risk variant associated with colorectal cancer risk in East Asians

Genome-wide association studies (GWAS) of colorectal cancer (CRC) have been conducted primarily in European descendants. In a GWAS conducted in East Asians, we first analyzed approximately 1.7 million single-nucleotide polymorphisms (SNPs) in four studies with 1,773 CRC cases and 2,642 controls. We then selected 66 promising SNPs for replication and genotyped them in three independent studies with 3,612 cases and 3,523 controls. Five SNPs were further evaluated using data from four additional studies including up to 3,290 cases and 4,339 controls. SNP rs7229639 in the SMAD7 gene was found to be associated with CRC risk with an odds ratio (95% confidence interval) associated with the minor allele (A) of 1.22 (1.15-1.29) in the combined analysis of all 11 studies (p = 2.93 × 10(-11) ). SNP rs7229639 is 2,487 bp upstream from rs4939827, a risk variant identified previously in a European-ancestry GWAS in relation to CRC risk. However, these two SNPs are not correlated in East Asians (r(2)  = 0.008) nor in Europeans (r(2)  = 0.146). The CRC association with rs7229639 remained statistically significant after adjusting for rs4939827 as well as three additional CRC risk variants (rs58920878, rs12953717 and rs4464148) reported previously in this region. SNPs rs7229639 and rs4939827 explained approximately 1% of the familial relative risk of CRC in East Asians. This study identifies a new CRC risk variant in the SMAD7 gene, further highlighting the significant role of this gene in the etiology of CRC.

Melanoma risk loci as determinants of melanoma recurrence and survival

Background

Steadily high melanoma mortality rates urge for the availability of novel biomarkers with a more personalized ability to predict melanoma clinical outcomes. Germline risk variants are promising candidates for this purpose; however, their prognostic potential in melanoma has never been systematically tested.

Methods

We examined the effect of 108 melanoma susceptibility single nucleotide polymorphisms (SNPs), associated in recent GWAS with melanoma and melanoma-related phenotypes, on recurrence-free survival (RFS) and overall survival (OS), in 891 prospectively accrued melanoma patients. Cox proportional hazards models (Cox PH) were used to test the associations between 108 melanoma risk SNPs and RFS and OS adjusted by age at diagnosis, gender, tumor stage, histological subtype and other primary tumor characteristics.

Results

We identified significant associations for rs7538876 (RCC2) with RFS (HR = 1.48, 95% CI = 1.20-1.83, p = 0.0005) and rs9960018 (DLGAP1) with both RFS and OS (HR = 1.43, 95% CI = 1.07-1.91, p = 0.01, HR = 1.52, 95% CI = 1.09-2.12, p = 0.01, respectively) using multivariable Cox PH models. In addition, we developed a logistic regression model that incorporates rs7538876, rs9960018, primary tumor histological type and stage at diagnosis that has an improved discriminatory ability to classify 3-year recurrence (AUC = 82%) compared to histological type and stage alone (AUC = 78%).

Conclusions

We identified associations between melanoma risk variants and melanoma outcomes. The significant associations observed for rs7538876 and rs9960018 suggest a biological implication of these loci in melanoma progression. The observed predictive patterns of associated variants with clinical end-points suggest for the first time the potential for utilization of genetic risk markers in melanoma prognostication.

Genetic susceptibility variants associated with colorectal cancer prognosis

Colorectal cancer (CRC) is the second leading cause of cancer-related death among men and women in Western countries. Once a tumour develops, a differentiated prognosis could be determined by lifestyle habits or inherited and somatic genetic factors. Finding such prognostic factors will be helpful in order to identify cases with a shorter survival or at a higher risk of recurrence that may benefit from more intensive treatment and follow-up surveillance. Sixteen CRC genetic susceptibility variants were directly genotyped in a cohort of 1235 CRC patients recruited by the EPICOLON Spanish consortium. Univariate Cox and multivariate regression analyses were performed taking as primary outcomes overall survival (OS), disease-free survival and recurrence-free interval. Genetic variants rs9929218 at 16q22.1 and rs10795668 at 10p14 may have an effect on OS. The G allele of rs9929218 was linked with a better OS [GG genotype, genotypic model: hazard ratio (HR) = 0.65, 95% confidence interval (CI) 0.45-0.93, P = 0.0179; GG/GA genotypes, dominant model: HR = 0.66, 95% CI 0.47-0.94, P = 0.0202]. Likewise, the G allele of rs10795668 was associated with better clinical outcome (GG genotype, genotypic model: HR = 0.73, 95% CI 0.53-1.01, P = 0.0570; GA genotype, genotypic model: HR = 0.66, 95% CI 0.47-0.92, P = 0.0137; GG/GA genotypes, dominant model: HR = 0.68, 95% CI 0.50-0.94, P = 0.0194). In conclusion, CRC susceptibility variants rs9929218 and rs10795668 may exert some influence in modulating patient's survival and they deserve to be further tested in additional CRC cohorts in order to confirm their potential as prognosis or predictive biomarkers.

Phenotypic and tumor molecular characterization of colorectal cancer in relation to a susceptibility SMAD7 variant associated with survival

The minor allele (G) of rs4939827, a SMAD7 (18q21) intronic variant, is associated with a lower risk of developing colorectal cancer (CRC) and poorer survival after diagnosis. Our objective was to evaluate the associations of this variant with different tumor phenotype and intratumoral molecular characteristics. We evaluated 1509 CRC cases and 2307 age-matched controls nested within the Nurses' Health Study and the Health Professionals Follow-up Study. We used the TaqMan assay to genotype rs4939827 and logistic regression to assess the association of rs4939827 with risk of CRC according to different phenotypic and molecular characteristics. We found that the minor allele (G) in rs4939827 (SMAD7, 18q21) was associated with a lower risk of developing tumor stage pT1 or pT2 CRC [multivariate odds ratio (OR), 0.73; 95% confidence interval (CI) 0.62-0.87] but not tumor stage pT3 or pT4 (multivariate OR, 1.07; 95% CI 0.93-1.23, P for heterogeneity = 1.2 × 10(-4)). The association between rs4939827 and CRC also significantly differed by methylation of RUNX3 (P for heterogeneity = 0.005). Among those with CRC, the minor allele (G) in rs4939827 was significantly associated with poorer overall survival (hazards ratio, 1.20; 95% CI, 1.02-1.42). We can conclude that the minor allele (G) of the germline intronic SMAD7 variant rs4939827 is associated with a lower risk of CRC with earlier tumor stage and CRC without methylation of the tumor suppressor RUNX3. These findings suggest that individuals with this SMAD7 variant that develop CRC are more probably to have tumors with greater invasiveness and methylation of RUNX3, which potentially contributes to their poorer observed survival.

Common single-nucleotide polymorphisms in the estrogen receptor β promoter are associated with colorectal cancer survival in postmenopausal women

Loss of estrogen receptor β (ERβ) expression in the gut is associated with colorectal cancer (CRC) initiation and progression. Germline single-nucleotide polymorphisms (SNP) in genes for the sex-steroid hormone receptors are not strongly associated with CRC risk; however, these SNPs have not previously been evaluated in relation to survival after diagnosis. We enrolled 729 women, ages 50 to 74, diagnosed with invasive CRC between 1997 and 2002 in 13 counties covered by the Seattle-Puget Sound Surveillance Epidemiology and End Results cancer registry. Participants provided germline DNA. We selected 99 tag-SNPs for the androgen receptor (AR), ERα (ESR1), ERβ (ESR2), and progesterone receptor (PGR) genes. Mortality outcomes were ascertained from the National Death Index. During a median of 6.6 years of follow-up, 244 deaths occurred (161 from CRC). We identified 20 SNPs (12 of ESR2 and 8 of PGR) for replication in 1,729 women diagnosed with incident invasive CRC (555 deaths; 405 from CRC) from three prospective cohort studies that participate in the Genetics and Epidemiology of Colorectal Cancer Consortium. Three correlated SNPs in the promoter of ESR2 (rs2987983, rs3020443, and rs2978381) were statistically significant predictors of CRC-specific and overall survival. Minor alleles of each were associated with improved survival [for rs2987983, CRC-specific HR, 0.77; 95% confidence interval (CI), 0.60-0.99 in the initial study, and HR, 0.79; CI, 0.64-0.98 in replication]. No associations were noted for SNPs of AR, ESR1, or PGR. SNPs in the promoter of ESR2 may be important to pathways related to the association between ERβ and tumor progression and metastasis.