Pharmacogenomics in colorectal cancer: a genome-wide association study to predict toxicity after 5-fluorouracil or FOLFOX administration

The development of genotyping technologies has allowed for wider screening for inherited causes of variable outcomes following drug administration. We have performed a genome-wide association study (GWAS) on 221 colorectal cancer (CRC) patients that had been treated with 5-fluorouracil (5-FU), either alone or in combination with oxaliplatin (FOLFOX). A validation set of 791 patients was also studied. Seven SNPs (rs16857540, rs2465403, rs10876844, rs10784749, rs17626122, rs7325568 and rs4243761) showed evidence of association (pooled P-values 0.020, 9.426E-03, 0.010, 0.017, 0.042, 2.302E-04, 2.803E-03) with adverse drug reactions (ADRs). This is the first study to explore the genetic basis of inter-individual variation in toxicity responses to the administration of 5-FU or FOLFOX in CRC patients on a genome-wide scale.

Impact of current smoking on the clinical course of microscopic colitis

BACKGROUND

Whether current smoking worsens the clinical course of microscopic colitis (MC) is unknown. The aim was to evaluate the impact of smoking on the clinical course of MC.

METHODS

One hundred and eighty-four patients (72% women; age, 62.4 ± 1.1 years) with MC (118 collagenous colitis (CC) and 66 lymphocytic colitis (LC) were evaluated (39 of them were current smokers). In all the patients, smoking habits and clinical data at presentation, response to therapy, and clinical relapses during follow-up were prospectively recorded. Risk factors for clinical relapse were studied in 160 patients after a mean follow-up of 28 ± 1 months. Cox regression analysis was used to adjust for confounding variables.

RESULTS

Age at diarrhea onset was 63.0 ± 1.4 years in nonsmokers and 50.4 ± 2.1 years in current smokers (P < 0.001). There was no significant influence of smoking habit on either clinical symptoms at diagnosis or clinical remission rate. Clinical relapse rate was 25.5% for CC and 29.6% for LC, with the mean relapse-free time 28.8 months (95% confidence interval, 26.3-31.4) for CC and 26.9 months (95% confidence interval, 26-30.3) for LC (P = 0.5). Multivariate analysis showed that age at diagnosis (<50 years versus others; adjusted hazard ratio, 2.8; 95% confidence interval, 1.3-6; P = 0.01) was associated with risk of relapse of CC but not LC. Current smoking was not an independent risk factor for either CC or LC relapse.

CONCLUSIONS

Active smokers developed MC more than a decade before nonsmokers. Age at diagnosis, but not smoking, was an independent risk factor of relapse in patients with CC.

Risk of cancer in cases of suspected lynch syndrome without germline mutation

BACKGROUND & AIMS

Colorectal cancers (CRCs) with microsatellite instability (MSI) and a mismatch repair (MMR) immunohistochemical deficit without hypermethylation of the MLH1 promoter are likely to be caused by Lynch syndrome. Some patients with these cancers have not been found to have pathogenic germline mutations and are considered to have Lynch-like syndrome (LLS). The aim of this study was to determine the risk of cancer in families of patients with LLS.

METHODS

We studied a population-based cohort of 1705 consecutive patients, performing MSI tests and immunohistochemical analyses of MMR proteins. Patients were diagnosed with Lynch syndrome when they were found to have pathogenic germline mutations. Patients with MSI and loss of MSH2 and/or MSH6 expression, isolated loss of PMS2 or loss of MLH1 without MLH1 promoter hypermethylation, and no pathogenic mutation were considered to have LLS. The clinical characteristics of patients and the age- and sex-adjusted standardized incidence ratios (SIRs) of cancer in families were compared between groups.

RESULTS

The incidence of CRC was significantly lower in families of patients with LLS than in families with confirmed cases of Lynch syndrome (SIR for Lynch syndrome, 6.04; 95% confidence interval [CI], 3.58-9.54; SIR for LLS, 2.12; 95% CI, 1.16-3.56; P < .001). However, the incidence of CRC was higher in families of patients with LLS than in families with sporadic CRC (SIR for sporadic CRC, 0.48; 95% CI, 0.27-0.79; P < .001).

CONCLUSIONS

The risk of cancer in families with LLS is lower that of families with Lynch syndrome but higher than that of families with sporadic CRC. These results confirm the need for special screening and surveillance strategies for these patients and their relatives.

Abstract 1334: Implication of the 3′UTR region of TGFβR1 with MSS HNPCC and sporadic colorectal cancer

Background: Colorectal cancer (CRC) is among all common malignancies one with the highest percentage of familial clustering. Thus almost 20% of cases develop in families with at least another affected member. Individuals in these families have a higher risk of developing CRC. Known mutations responsible for several CRC syndromes only explain a small proportion of familial cases but the underlying basis of most still remains unknown. Over half of CRCs that are highly suspicious for an autosomal dominant hereditary pattern of malignancy, as expressed by the Amsterdam criteria, are not explained by known genetic mutations. These cases are known as microsatellite stable hereditary non-polyposis CRC (MSS-HNPCC) or colorectal cancer type X. Aims: To identify new genetic variants that can potentially modulate CRC risk and contribute to hereditability. Methods: We sequenced the coding sequence of MGMT, AXIN2, CTNNB1, TGFβRI and TGFβRII genes and we genotyped 10 common low risk variants, in 30 MSS-HNPCC patients. Potentially relevant variants were genotyped in 308 sporadic cases and 425 cancer-free controls. Logistic regression was used to estimate cancer risk (OR (95%CI)) associated with the genetic variants identified using SPSS (IBM v20.0). Results: A haplotype containing 3 variants (rs67687202, rs868 and rs334354) in high linkage disequilibrium (LD) was found to be associated in a very strong manner with MSS-HNPCC patients and to a lesser degree with sporadic CRC. Thus both MSS-HNPCC and sporadic CRC showed a significantly lower minor allele frequency (MAF) than controls (MAF 0.07, MAF 0.23 vs MAF 0.29) for rs67687202. The AA genotype of rs868 associates with a strong risk for CRC in MSS-HNPCC patients (OR=7.9 (2.7-23.1) P&lt;0.001) and also in sporadic CRC patients but much more modestly (OR=1.6 (1.2-2.2) P=0.001). According to prediction models, the AA genotype for rs868 results in a tighter complementary binding for the family of let-7 miRNAs, which inhibits TGFβR1 translation. On the other hand, the GG genotype increases the hybridization energy of binding for miR-98 and let-7c and completely eliminates the binding for let-7d. We did not identify any association of 10 low risk variants or an accumulation of these risk alleles in MSS-HNPCC patients, which suggests that clustering of common risk alleles is not contributing to cancer development in these families. Conclusions: We describe for the first time a haplotype presumably involved in controlling TGFβR1 expression that has an extremely high association with MSS-HNPCC suggesting a deep contribution of this genetic component to familial CRC. The effect could be due to the more efficient binding of miRNA let-7, which inhibits the TGFβR1 transcript. This further supports other findings that suggest the important role of TGFβR1 as a susceptibility factor in CRC. An accumulation of low susceptibility variants is an unlikely explanation for the high cancer risk in MSS-HNPCC.

Citation Format: Rosa M. Munoz Xicola, Brian Doyle, Jamie Rawson, Pilar Garre, Anna Abuli, Esther Lee, Sathyaraj Murugappan, Xavier Bessa, Luis Bujanda, Francesc Balaguer, Sergi Castellvi-Bel, Juan Clofent, Cristina Alenda, Rodrigo Jover, Clara Ruiz-Ponte, Sapna Singal, Montserrat Andreu, Angel Carracedo, Antoni Castells, Nathan Ellis, Trinidad Caldes, Xavier LLor. Implication of the 3′UTR region of TGFβR1 with MSS HNPCC and sporadic colorectal cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1334. doi:10.1158/1538-7445.AM2013-1334

New genetic associations in thiopurine-related bone marrow toxicity among inflammatory bowel disease patients

Background: The toxicity related to thiopurine drug therapy for inflammatory bowel disease (IBD) varies widely among patients. Almost 15–30% of patients with IBD develop side effects during treatment, often bone marrow suppression. Several factors have been implicated in determining this toxicity, mainly individual genetic variation related to formation of active thiopurine metabolites. The aim was to identify genes involved in thiopurine-related myelosuppression. Materials & methods: A two-stage investigation of 19,217 coding SNPs (cSNPs) was performed in a Spanish (Inflammatory Bowel Disease Group of Galicia [EIGA]) cohort of 173 IBD patients, 15 with bone marrow suppression. The top 20 cSNPs identified in the first stage with p < 10-3 for allelic test association and SNPs that define the common TPMT alleles were replicated in a different Spanish (ENEIDA) cohort (87 patients, 29 with bone marrow suppression). Results: Several cSNPs showed a significant p-value in the allelic joint analysis (p-Cochran–Mantel–Haenszel test ≤2.55 × 10-3) despite no cSNP passing correction for multiple testing in the first cohort. Of note is rs3729961 in the gene IL6ST, a transducer signal chain shared by many cytokines including IL6 (p-value combined = 2.36 × 10-4, odds ratio [95% CI]: 3.41 [1.71–6.78]). In addition, we detected association with rs3749598 in the FSTL5 gene that appears to interact with metalloproteases at the extracellular matrix level (p-value combined = 4.89 × 10-4), odds ratio (95% CI): 3.67 (1.68–8.01). Conclusion: We have identified IL6ST and FSLT5 as new bone marrow suppression susceptibility candidate genes after thiopurine treatment in IBD patients. This is the first report of variants associated with thiopurine-related myelosuppression that was identified by a genome-wide association study. Its validation awaits functional analyses and replication in additional studies.

Original submitted 14 September 2012; Revision submitted 13 February 2013

Modifiable endoscopic factors that influence the adenoma detection rate in colorectal cancer screening colonoscopies

BACKGROUND

Adenoma detection rate (ADR) has become the most important quality indicator for colonoscopy.

OBJECTIVE

The aim of this study was to investigate which modifiable factors, directly related to the endoscopic procedure, influenced the ADR in screening colonoscopies.

DESIGN

Observational, nested study.

SETTING

Multicenter, randomized, controlled trials.

PATIENTS

Asymptomatic people aged 50 to 69 years were eligible for a multicenter, randomized, controlled trial designed to compare colonoscopy and fecal immunochemical testing in colorectal cancer screening. A total of 4539 individuals undergoing a direct screening colonoscopy were included in this study.

INTERVENTION

Colonoscopy.

MAIN OUTCOME MEASUREMENTS

Bowel cleansing, sedation, withdrawal time in normal colonoscopies, and cecal intubation were analyzed as possible predictors of adenoma detection by using logistic regression analysis, adjusted for age and sex.

RESULTS

In multivariate analysis, after adjustment for age and sex, factors independently related to the ADR were a mean withdrawal time longer than 8 minutes (odds ratio [OR] 1.51; 95% CI, 1.17-1.96) in normal colonoscopies and split preparation (OR 1.26; 95% CI, 1.01-1.57). For advanced adenomas, only withdrawal time maintained statistical significance in the multivariate analysis. For proximal adenomas, withdrawal time and cecal intubation maintained independent statistical significance, whereas only withdrawal time longer than 8 minutes and a <10-hour period between the end of preparation and colonoscopy showed independent associations for distal adenomas.

LIMITATIONS

Only endoscopic variables have been analyzed.

CONCLUSION

Withdrawal time was the only modifiable factor related to the ADR in colorectal cancer screening colonoscopies associated with an increased detection rate of overall, advanced, proximal, and distal adenomas.

BMP2/BMP4 colorectal cancer susceptibility loci in northern and southern European populations

Genome-wide association studies have successfully identified 20 colorectal cancer susceptibility loci. Amongst these, four of the signals are defined by tagging single nucleotide polymorphisms (SNPs) on regions 14q22.2 (rs4444235 and rs1957636) and 20p12.3 (rs961253 and rs4813802). These markers are located close to two of the genes involved in bone morphogenetic protein (BMP) signaling (BMP4 and BMP2, respectively). By investigating these four SNPs in an initial cohort of Spanish origin, we found substantial evidence that minor allele frequencies (MAFs) may be different in northern and southern European populations. Therefore, we genotyped three additional southern European cohorts comprising a total of 2028 cases and 4273 controls. The meta-analysis results show that only one of the association signals (rs961253) is effectively replicated in the southern European populations, despite adequate power to detect all four. The other three SNPs (rs4444235, rs1957636 and rs4813802) presented discordant results in MAFs and linkage disequilibrium patterns between northern and southern European cohorts. We hypothesize that this lack of replication could be the result of differential tagging of the functional variant in both sets of populations. Were this true, it would have complex consequences in both our ability to understand the nature of the real causative variants, as well as for further study designs.

Epidemiological risk factors in microscopic colitis: a prospective case-control study

BACKGROUND

The cause of collagenous colitis (CC) and lymphocytic colitis (LC) is unknown and epidemiological risk factors for CC and LC are not well studied. The aim was to evaluate in a case-control study epidemiological risk factors for CC and LC.

METHODS

In all, 120 patients with CC, 70 with CL, and 128 controls were included. For all cases and controls information was prospectively recorded. A binary logistic regression analysis was performed separately for CC and LC.

RESULTS

Independent associations observed with the diagnosis of CC were: current smoking (odds ratio [OR], 2.4), history of polyarthritis (OR, 20.8), and consumption of lansoprazole (OR, 6.4), low-dose aspirin (OR, 3.8), beta-blockers (OR, 3.6), and angiotensin II receptor antagonists (OR 0.20). In the case of LC they were: current smoking (OR, 3.8), associated autoimmune diseases (OR, 8), and consumption of sertraline (OR, 17.5), omeprazole (OR 2.7), low-dose aspirin (OR, 4.7), and oral antidiabetic drugs (OR, 0.14).

CONCLUSIONS

The consumption of drugs, current smoking, and associated autoimmune diseases were independently associated with the risk of microscopic colitis.

A colorectal cancer genome-wide association study in a Spanish cohort identifies two variants associated with colorectal cancer risk at 1p33 and 8p12

BACKGROUND

Colorectal cancer (CRC) is a disease of complex aetiology, with much of the expected inherited risk being due to several common low risk variants. Genome-Wide Association Studies (GWAS) have identified 20 CRC risk variants. Nevertheless, these have only been able to explain part of the missing heritability. Moreover, these signals have only been inspected in populations of Northern European origin.

RESULTS

Thus, we followed the same approach in a Spanish cohort of 881 cases and 667 controls. Sixty-four variants at 24 loci were found to be associated with CRC at p-values <10-5. We therefore evaluated the 24 loci in another Spanish replication cohort (1481 cases and 1850 controls). Two of these SNPs, rs12080929 at 1p33 (Preplication=0.042; Ppooled=5.523x10-03; OR (CI95%)=0.866(0.782-0.959)) and rs11987193 at 8p12 (Preplication=0.039; Ppooled=6.985x10-5; OR (CI95%)=0.786(0.705-0.878)) were replicated in the second Phase, although they did not reach genome-wide statistical significance.

CONCLUSIONS

We have performed the first CRC GWAS in a Southern European population and by these means we were able to identify two new susceptibility variants at 1p33 and 8p12 loci. These two SNPs are located near the SLC5A9 and DUSP4 loci, respectively, which could be good functional candidates for the association signals. We therefore believe that these two markers constitute good candidates for CRC susceptibility loci and should be further evaluated in other larger datasets. Moreover, we highlight that were these two SNPs true susceptibility variants, they would constitute a decrease in the CRC missing heritability fraction.

Identification of Lynch syndrome among patients with colorectal cancer

CONTEXT

Lynch syndrome is the most common form of hereditary colorectal cancer (CRC) and is caused by germline mutations in DNA mismatch repair (MMR) genes. Identification of gene carriers currently relies on germline analysis in patients with MMR-deficient tumors, but criteria to select individuals in whom tumor MMR testing should be performed are unclear.

OBJECTIVE

To establish a highly sensitive and efficient strategy for the identification of MMR gene mutation carriers among CRC probands.

DESIGN, SETTING, AND PATIENTS

Pooled-data analysis of 4 large cohorts of newly diagnosed CRC probands recruited between 1994 and 2010 (n = 10,206) from the Colon Cancer Family Registry, the EPICOLON project, the Ohio State University, and the University of Helsinki examining personal, tumor-related, and family characteristics, as well as microsatellite instability, tumor MMR immunostaining, and germline MMR mutational status data.

MAIN OUTCOME

Performance characteristics of selected strategies (Bethesda guidelines, Jerusalem recommendations, and those derived from a bivariate/multivariate analysis of variables associated with Lynch syndrome) were compared with tumor MMR testing of all CRC patients (universal screening).

RESULTS

Of 10,206 informative, unrelated CRC probands, 312 (3.1%) were MMR gene mutation carriers. In the population-based cohorts (n = 3671 probands), the universal screening approach (sensitivity, 100%; 95% CI, 99.3%-100%; specificity, 93.0%; 95% CI, 92.0%-93.7%; diagnostic yield, 2.2%; 95% CI, 1.7%-2.7%) was superior to the use of Bethesda guidelines (sensitivity, 87.8%; 95% CI, 78.9%-93.2%; specificity, 97.5%; 95% CI, 96.9%-98.0%; diagnostic yield, 2.0%; 95% CI, 1.5%-2.4%; P < .001), Jerusalem recommendations (sensitivity, 85.4%; 95% CI, 77.1%-93.6%; specificity, 96.7%; 95% CI, 96.0%-97.2%; diagnostic yield, 1.9%; 95% CI, 1.4%-2.3%; P < .001), and a selective strategy based on tumor MMR testing of cases with CRC diagnosed at age 70 years or younger and in older patients fulfilling the Bethesda guidelines (sensitivity, 95.1%; 95% CI, 89.8%-99.0%; specificity, 95.5%; 95% CI, 94.7%-96.1%; diagnostic yield, 2.1%; 95% CI, 1.6%-2.6%; P < .001). This selective strategy missed 4.9% of Lynch syndrome cases but resulted in 34.8% fewer cases requiring tumor MMR testing and 28.6% fewer cases undergoing germline mutational analysis than the universal approach.

CONCLUSION

Universal tumor MMR testing among CRC probands had a greater sensitivity for the identification of Lynch syndrome compared with multiple alternative strategies, although the increase in the diagnostic yield was modest.

Effectiveness of infliximab after adalimumab failure in Crohn's disease

AIM: To evaluate the effectiveness of infliximab as a second-line therapy in Crohn’s disease patients after adalimumab failure.

METHODS: A historical cohort study in a community-based gastroenterology practice evaluated Crohn’s disease patients treated with infliximab (induction plus maintenance) after adalimumab failure. Patients were identified using a large Spanish database (ENEIDA).

RESULTS: We included 15 Crohn’s disease patients who received infliximab after adalimumab failure. Five patients discontinued adalimumab due to loss of response, 3 due to adverse events and 7 due to partial response. After infliximab therapy was started, all patients who had interrupted adalimumab due to loss of efficacy regained response. All patients who discontinued adalimumab due to adverse events responded to infliximab and maintained this response; one of these patients had an uneventful course on infliximab, but 2 developed adverse events. None of the 7 patients who interrupted adalimumab due to partial response reached remission with infliximab.

CONCLUSION: Switching from adalimumab to infliximab may be useful in patients who develop adverse effects or loss of response, however, the benefit of infliximab in primary nonresponders was not established.

A high degree of LINE-1 hypomethylation is a unique feature of early-onset colorectal cancer

OBJECTIVE

Early-onset colorectal cancer (CRC) represents a clinically distinct form of CRC that is often associated with a poor prognosis. Methylation levels of genomic repeats such as LINE-1 elements have been recognized as independent factors for increased cancer-related mortality. The methylation status of LINE-1 elements in early-onset CRC has not been analyzed previously.

DESIGN

We analyzed 343 CRC tissues and 32 normal colonic mucosa samples, including 2 independent cohorts of CRC diagnosed ≤ 50 years old (n=188), a group of sporadic CRC >50 years (MSS n=89; MSI n=46), and a group of Lynch syndrome CRCs (n=20). Tumor mismatch repair protein expression, microsatellite instability status, LINE-1 and MLH1 methylation, somatic BRAF V600E mutation, and germline MUTYH mutations were evaluated.

RESULTS

Mean LINE-1 methylation levels (± SD) in the five study groups were early-onset CRC, 56.6% (8.6); sporadic MSI, 67.1% (5.5); sporadic MSS, 65.1% (6.3); Lynch syndrome, 66.3% (4.5) and normal mucosa, 76.5% (1.5). Early-onset CRC had significantly lower LINE-1 methylation than any other group (p<0.0001). Compared to patients with <65% LINE-1 methylation in tumors, those with ≥ 65% LINE-1 methylation had significantly better overall survival (p=0.026, log rank test).

CONCLUSIONS

LINE-1 hypomethylation constitutes a potentially important feature of early-onset CRC, and suggests a distinct molecular subtype. Further studies are needed to assess the potential of LINE-1 methylation status as a prognostic biomarker for young people with CRC.

Comparison between universal molecular screening for Lynch syndrome and revised Bethesda guidelines in a large population-based cohort of patients with colorectal cancer

BACKGROUND

The selection of patients for genetic testing to rule out Lynch syndrome is currently based on fulfilment of at least one of the revised Bethesda criteria followed by mismatch repair (MMR) status analysis. A study was undertaken to compare the present approach with universal MMR study-based strategies to detect Lynch syndrome in a large series of patients with colorectal cancer (CRC).

METHODS

2093 patients with CRC from the EPICOLON I and II cohorts were included. Immunohistochemistry for MMR proteins and/or microsatellite instability (MSI) analysis was performed in tumour tissue. Germline MLH1 and MSH2 mutation analysis was performed in patients whose tumours showed loss of MLH1 or MSH2 staining, respectively. MSH6 genetic testing was done in patients whose tumours showed lack of MSH6 expression or a combined lack of MSH2 and MSH6 expression but did not have MSH2 mutations. PMS2 genetic testing was performed in patients showing isolated loss of PMS2 expression. In patients with MSI tumours and normal or not available MMR protein expression, all four MMR genes were studied.

RESULTS

A total of 180 patients (8.6%) showed loss of expression of some of the MMR proteins and/or MSI. Four hundred and eighty-six patients (23.2%) met some of the revised Bethesda criteria. Of the 14 (0.7%) patients who had a MMR gene mutation, 12 fulfilled at least one of the revised Bethesda criteria and two (14.3%) did not.

CONCLUSIONS

Routine molecular screening of patients with CRC for Lynch syndrome using immunohistochemistry or MSI has better sensitivity for detecting mutation carriers than the Bethesda guidelines.

Ulcerative colitis impairs the acylethanolamide-based anti-inflammatory system reversal by 5-aminosalicylic acid and glucocorticoids

Studies in animal models and humans suggest anti-inflammatory roles on the N-acylethanolamide (NAE)-peroxisome proliferators activated receptor alpha (PPARα) system in inflammatory bowel diseases. However, the presence and function of NAE-PPARα signaling system in the ulcerative colitis (UC) of humans remain unknown as well as its response to active anti-inflammatory therapies such as 5-aminosalicylic acid (5-ASA) and glucocorticoids. Expression of PPARα receptor and PPARα ligands-biosynthetic (NAPE-PLD) and -degrading (FAAH and NAAA) enzymes were analyzed in untreated active and 5-ASA/glucocorticoids/immunomodulators-treated quiescent UC patients compared to healthy human colonic tissue by RT-PCR and immunohistochemical analyses. PPARα, NAAA, NAPE-PLD and FAAH showed differential distributions in the colonic epithelium, lamina propria, smooth muscle and enteric plexus. Gene expression analysis indicated a decrease of PPARα, PPARγ and NAAA, and an increase of FAAH and iNOS in the active colitis mucosa. Immunohistochemical expression in active colitis epithelium confirmed a PPARα decrease, but showed a sharp NAAA increase and a NAPE-PLD decrease, which were partially restored to control levels after treatment. We also characterized the immune cells of the UC mucosa infiltrate. We detected a decreased number of NAAA-positive and an increased number of FAAH-positive immune cells in active UC, which were partially restored to control levels after treatment. NAE-PPARα signaling system is impaired during active UC and 5-ASA/glucocorticoids treatment restored its normal expression. Since 5-ASA actions may work through PPARα and glucocorticoids through NAE-producing/degrading enzymes, the use of PPARα agonists or FAAH/NAAA blockers that increases endogenous PPARα ligands may yield similar therapeutics advantages.

Seeking genetic susceptibility variants for colorectal cancer: the EPICOLON consortium experience

The EPICOLON consortium was initiated in 1999 by the Gastrointestinal Oncology Group of the Spanish Gastroenterology Association. It recruited consecutive, unselected, population-based colorectal cancer (CRC) cases and control subjects matched by age and gender without personal or familial history of cancer all over Spain with the main goal of gaining knowledge in Lynch syndrome and familial CRC. This epidemiological, prospective and multicentre study collected extensive clinical data and biological samples from ∼2000 CRC cases and 2000 controls in Phases 1 and 2 involving 25 and 14 participating hospitals, respectively. Genetic susceptibility projects in EPICOLON have included candidate-gene approaches evaluating single-nucleotide polymorphisms/genes from the historical category (linked to CRC risk by previous studies), from human syntenic CRC susceptibility regions identified in mouse, from the CRC carcinogenesis-related pathways Wnt and BMP, from regions 9q22 and 3q22 with positive linkage in CRC families, and from the mucin gene family. This consortium has also participated actively in the identification 5 of the 16 common, low-penetrance CRC genetic variants identified so far by genome-wide association studies. Finishing their own pangenomic study and performing whole-exome sequencing in selected CRC samples are among EPICOLON future research prospects.

Long-term durability of response to adalimumab in Crohn's disease

BACKGROUND

Adalimumab is an effective treatment for Crohn's disease (CD), but may also be associated with loss of response. Few reports provide insight into the durability of treatment of CD with adalimumab for periods longer than 12 months in clinical practice.

AIMS

To evaluate the long-term durability of adalimumab maintenance treatment and to identify predictive factors associated with loss of response.

METHODS

CD patients who initially responded to adalimumab were evaluated in a historical cohort study. Maintenance of long-term response was estimated using Kaplan-Meier analysis. Cox regression analysis was performed to identify potential predictive factors for loss of efficacy.

RESULTS

In all, 380 CD patients were included (mean age, 38 years; 52% female). Of these, 43% had ileocolic CD, 50% inflammatory CD, and 41% perianal CD. Median follow-up with adalimumab was 8 months (range, 4-75 months). The annual risk of loss of response to adalimumab was 18% per patient-year of follow-up. Twenty-eight percent of patients were anti-TNF-naïve and 72% anti-TNF-experienced. The loss of efficacy was 8% per patient-year of follow-up in the anti-TNF-naïve patients and 22% in the anti-TNF-experienced group (P < 0.01). In the multivariate analysis, the presence of extraintestinal manifestations (hazard ratio [HR] = 1.7; 95% confidence interval [CI] = 1.02-2.9) and previous experience with other anti-TNF agents (HR = 2.5,95% CI = 1.2-5.3) were associated with higher risk of loss of efficacy.

CONCLUSIONS

A relevant proportion of CD patients on long-term adalimumab lost response. The risk of loss of response was higher (more than 2-fold) in anti-TNF-experienced than in anti-TNF-naïve patients (22% vs. 8% per patient-year of treatment). Having extraintestinal manifestations seems to increase the risk of loss of efficacy.

Colonoscopy versus fecal immunochemical testing in colorectal-cancer screening

BACKGROUND

Colonoscopy and fecal immunochemical testing (FIT) are accepted strategies for colorectal-cancer screening in the average-risk population.

METHODS

In this randomized, controlled trial involving asymptomatic adults 50 to 69 years of age, we compared one-time colonoscopy in 26,703 subjects with FIT every 2 years in 26,599 subjects. The primary outcome was the rate of death from colorectal cancer at 10 years. This interim report describes rates of participation, diagnostic findings, and occurrence of major complications at completion of the baseline screening. Study outcomes were analyzed in both intention-to-screen and as-screened populations.

RESULTS

The rate of participation was higher in the FIT group than in the colonoscopy group (34.2% vs. 24.6%, P<0.001). Colorectal cancer was found in 30 subjects (0.1%) in the colonoscopy group and 33 subjects (0.1%) in the FIT group (odds ratio, 0.99; 95% confidence interval [CI], 0.61 to 1.64; P=0.99). Advanced adenomas were detected in 514 subjects (1.9%) in the colonoscopy group and 231 subjects (0.9%) in the FIT group (odds ratio, 2.30; 95% CI, 1.97 to 2.69; P<0.001), and nonadvanced adenomas were detected in 1109 subjects (4.2%) in the colonoscopy group and 119 subjects (0.4%) in the FIT group (odds ratio, 9.80; 95% CI, 8.10 to 11.85; P<0.001).

CONCLUSIONS

Subjects in the FIT group were more likely to participate in screening than were those in the colonoscopy group. On the baseline screening examination, the numbers of subjects in whom colorectal cancer was detected were similar in the two study groups, but more adenomas were identified in the colonoscopy group. (Funded by Instituto de Salud Carlos III and others; ClinicalTrials.gov number, NCT00906997.).

Susceptibility genetic variants associated with early-onset colorectal cancer

Colorectal cancer (CRC) is the second most common cancer in Western countries. Hereditary forms only correspond to 5% of CRC burden. Recently, genome-wide association studies have identified common low-penetrant CRC genetic susceptibility loci. Early-onset CRC (CRC<50 years old) is especially suggestive of hereditary predisposition although 85-90% of heritability still remains unidentified. CRC<50 patients (n = 191) were compared with a late-onset CRC group (CRC>65 years old) (n = 1264). CRC susceptibility variants at 8q23.3 (rs16892766), 8q24.21 (rs6983267), 10p14 (rs10795668), 11q23.1 (rs3802842), 15q13.3 (rs4779584), 18q21 (rs4939827), 14q22.2 (rs4444235), 16q22.1 (rs9929218), 19q13.1 (rs10411210) and 20p12.3 (rs961253) were genotyped in all DNA samples. A genotype-phenotype correlation with clinical and pathological characteristics in both groups was performed. Risk allele carriers for rs3802842 [Odds ratio (OR) = 1.5, 95% confidence interval (CI) 1.1-2.05, P = 0.0096, dominant model) and rs4779584 (OR = 1.39, 95% CI 1.02-1.9, P = 0.0396, dominant model) were more frequent in the CRC<50 group, whereas homozygotes for rs10795668 risk allele were also more frequent in the early-onset CRC (P = 0.02, codominant model). Regarding early-onset cases, 14q22 (rs4444235), 11q23 (rs3802842) and 20p12 (rs961253) variants were more associated with family history of CRC or tumors of the Lynch syndrome spectrum excluding CRC. In our entire cohort, sum of risk alleles was significantly higher in patients with a CRC family history (OR = 1.40, 95% CI 1.06-1.85, P = 0.01). In conclusion, variants at 10p14 (rs10795668), 11q23.1 (rs3802842) and 15q13.3 (rs4779584) may have a predominant role in predisposition to early-onset CRC. Association of CRC susceptibility variants with some patient's familiar and personal features could be relevant for screening and surveillance strategies in this high-risk group and it should be explored in further studies.

Validation Microsatellite Path Score in a Population-Based Cohort of Patients With Colorectal Cancer

Purpose

Bethesda guidelines are used to recognize patients at risk for Lynch syndrome. However, obtaining personal and familial tumor data can sometimes be difficult. The Microsatellite Path Score (MsPath), a pathological score, based on age, tumor location, and pathologic features, has been developed to effectively predict colorectal cancer with DNA mismatch repair (MMR) deficiencies. However, the MsPath model's performance in an unselected, population-based colorectal cancer (CRC) population is unknown.

Patients and Methods

We analyzed all patients with CRC regardless of age, personal or family history, and tumor characteristics from the EPICOLON study, an independent, prospective, multicenter, population-based cohort (N = 1,222). All patients underwent tumor microsatellite instability (MSI) analysis and immunostaining for MLH1/MSH2, and those with MMR underwent tumor BRAF mutation analysis and MLH1/MSH2 germline testing. All the pathologic features were centralized and evaluated blinded to the MMR status.

Results

MsPath score for prediction of having MSI high, with the recommended MsPath cutoff score ≥1.0, had a sensitivity, specificity, and positive predictive value (PPV) of 92.8% (95% CI, 86.9 to 98.3), 64.1% (95% CI, 61.1 to 66.8), and 15.8% (95% CI, 12.2 to 18.6), respectively. MsPath score had a sensitivity, specificity, and PPV of 81.8% (95% CI, 59.0 to 99.8), 60.6% (95% CI, 57.8 to 63.4), and 1.9% (95% CI, 0.7 to 3.1), respectively, for the identification of MLH1/MSH2 gene carriers. Application of the MsPath score, resulted in two (18%) of 11 mutation carriers being missed, both pathogenic germline MSH2 mutations.

Conclusion

In the general nonselected population, the MsPath score accurately predicted the probability of bearing a MSI high CRC, but it was insufficiently accurate to use for the selection of patients warranting MLH1/MSH2 mutation testing in the setting of Lynch syndrome.

Case-control study for colorectal cancer genetic susceptibility in EPICOLON: previously identified variants and mucins

Background

Colorectal cancer (CRC) is the second leading cause of cancer death in developed countries. Familial aggregation in CRC is also important outside syndromic forms and, in this case, a polygenic model with several common low-penetrance alleles contributing to CRC genetic predisposition could be hypothesized. Mucins and GALNTs (N-acetylgalactosaminyltransferase) are interesting candidates for CRC genetic susceptibility and have not been previously evaluated. We present results for ten genetic variants linked to CRC risk in previous studies (previously identified category) and 18 selected variants from the mucin gene family in a case-control association study from the Spanish EPICOLON consortium.

Methods

CRC cases and matched controls were from EPICOLON, a prospective, multicenter, nationwide Spanish initiative, comprised of two independent stages. Stage 1 corresponded to 515 CRC cases and 515 controls, whereas stage 2 consisted of 901 CRC cases and 909 controls. Also, an independent cohort of 549 CRC cases and 599 controls outside EPICOLON was available for additional replication. Genotyping was performed for ten previously identified SNPs in ADH1C, APC, CCDN1, IL6, IL8, IRS1, MTHFR, PPARG, VDR and ARL11, and 18 selected variants in the mucin gene family.

Results

None of the 28 SNPs analyzed in our study was found to be associated with CRC risk. Although four SNPs were significant with a P-value < 0.05 in EPICOLON stage 1 [rs698 in ADH1C (OR = 1.63, 95% CI = 1.06-2.50, P-value = 0.02, recessive), rs1800795 in IL6 (OR = 1.62, 95% CI = 1.10-2.37, P-value = 0.01, recessive), rs3803185 in ARL11 (OR = 1.58, 95% CI = 1.17-2.15, P-value = 0.007, codominant), and rs2102302 in GALNTL2 (OR = 1.20, 95% CI = 1.00-1.44, P-value = 0.04, log-additive 0, 1, 2 alleles], only rs3803185 achieved statistical significance in EPICOLON stage 2 (OR = 1.34, 95% CI = 1.06-1.69, P-value = 0.01, recessive). In the joint analysis for both stages, results were only significant for rs3803185 (OR = 1.12, 95% CI = 1.00-1.25, P-value = 0.04, log-additive 0, 1, 2 alleles) and borderline significant for rs698 and rs2102302. The rs3803185 variant was not significantly associated with CRC risk in an external cohort (MCC-Spain), but it still showed some borderline significance in the pooled analysis of both cohorts (OR = 1.08, 95% CI = 0.98-1.18, P-value = 0.09, log-additive 0, 1, 2 alleles).

Conclusions

ARL11, ADH1C, GALNTL2 and IL6 genetic variants may have an effect on CRC risk. Further validation and meta-analyses should be undertaken in larger CRC studies.