Colibactin mutational signatures in NTHL1 tumor syndrome and MUTYH associated polyposis patients.

Polyketide synthase (pks) island harboring Escherichia coli are, under the right circumstances, able to produce the genotoxin colibactin. Colibactin is a risk factor for the development of colorectal cancer and associated with mutational signatures SBS88 and ID18. This study explores colibactin-associated mutational signatures in biallelic NTHL1 and MUTYH patients. Targeted Next Generation Sequencing (NGS) was performed on colorectal adenomas and carcinomas of one biallelic NTHL and 12 biallelic MUTYH patients. Additional fecal metagenomics and genome sequencing followed by mutational signature analysis was conducted for the NTHL1 patient. Targeted NGS of the NTHL1 patient showed somatic APC variants fitting SBS88 which was confirmed using WGS. Furthermore, fecal metagenomics revealed pks genes. Also, in 1 out of 11 MUTYH patient a somatic variant was detected fitting SBS88. This report shows that colibactin may influence development of colorectal neoplasms in predisposed patients.

Validity of a two-antibody testing algorithm for mismatch repair deficiency testing in cancer; a systematic literature review and meta-analysis.

Reflex mismatch repair immunohistochemistry (MMR IHC) testing for MLH1, PMS2, MSH2 and MSH6 is used to screen for Lynch syndrome. Recently MMR-deficiency (MMRd) has been approved as a pan-cancer predictive biomarker for checkpoint inhibitor therapy, leading to a vast increase in the use of MMR IHC in clinical practice. We explored whether immunohistochemical staining with PMS2 and MSH6 can be used as a reliable substitute. This two-antibody testing algorithm has the benefit of saving tissue, cutting costs and saving time. PubMed, Embase and Cochrane library were systematically searched for articles reporting on MMR IHC. The weighed percentage of cases with isolated MLH1 or MSH2 loss or combined MLH1/MSH2 loss alone was analyzed using a random effects model meta-analysis in R. The search yielded 1704 unique citations, of which 131 studies were included, describing 9014 patients. A weighed percentage of 1.1% (95% CI 0.53-18.87, I = 87%) of cases with isolated MLH1 or MSH2 loss or combined MLH1/MSH2 loss alone was observed. In the six articles with the main aim of investigating the two-antibody testing algorithm all MMRd cases were detected with the two-antibody testing algorithm, there were no cases with isolated MLH1 or MSH2 loss or combined MLH1/MSH2 loss alone. This high detection rate of MMRd of the two-antibody testing algorithm supports its use in clinical practice by specialized pathologists. Staining of all four antibodies should remain the standard in cases with equivocal results of the two-antibody testing algorithm. Finally, educational sessions in which staining pattern pitfalls are discussed will continue to be important.

A unique case of two somatic APC mutations in an early onset cribriform-morular variant of papillary thyroid carcinoma and overview of the literature.

We report a case of a 22-year-old female patient who was diagnosed with a cribriform-morular variant of papillary thyroid carcinoma (CMV-PTC). While at early ages this thyroid cancer variant is highly suggestive for familial adenomatous polyposis (FAP), there was no family history of FAP. In the tumor biallelic, inactivating APC variants were identified. The patient tested negative for germline variants based on analysis of genomic DNA from peripheral blood leukocytes. Somatic mosaicism was excluded by subsequent deep sequencing of leukocyte and normal thyroid DNA using next generation sequencing (NGS). This report presents a rare sporadic case of CMV-PTC, and to the best of our knowledge the first featuring two somatic APC mutations underlying the disease, with an overview of CMV-PTC cases with detected APC and CTNNB1 pathogenic variants from the literature.

Targetable gene fusions identified in radioactive iodine refractory advanced thyroid carcinoma.

Objective Gene alterations leading to activation of the MAPK pathway are of interest for targeted therapy in patients with advanced radioactive iodine refractory (RAI-R) thyroid carcinoma. Due to technical reasons gene fusion analysis in RNA isolated from formalin-fixed tumor tissues has till now been limited. The objective of the present study was to identify targetable gene rearrangements in RNA isolated from formalin-fixed RAI-R thyroid carcinomas. Design Retrospective study in 132 patients with RAI-R thyroid carcinoma (59 papillary-, 24 follicular-, 35 Hürthle cell- and 14 anaplastic thyroid carcinoma). Methods Total nucleic acid (undivided DNA and RNA) was isolated from formalin-fixed tissue. Extensive gene fusion analysis was performed in all samples that tested negative for pathogenic BRAF, NRAS, HRAS and KRAS variants. Results Seven targetable gene fusions were identified in the remaining 60 samples without known DNA variants. This includes frequently reported gene fusions such as CCDC6/RET (PTC1), PRKAR1A/RET (PTC2) and ETV6/NTRK3 , and gene fusions that are less common in thyroid cancer (TPM3/NTRK1, EML4/ALK and EML4/NTRK3). Of note, most gene fusions were detected in papillary thyroid carcinoma and MAPK-associated alterations in Hürthle cell carcinomas are rare (2/35). Conclusion Targetable gene fusions were found in 12% of RAI-R thyroid carcinoma without DNA variants and can be effectively identified in formalin-fixed tissue. These gene fusions might provide a preclinical rationale to include specific kinase inhibitors in the treatment regimen for these patients. The latter intends to restore iodine transport and/or take advantage of the direct effect on tumor cell vitality once progressive disease is seen.

Scoring the tumor-stroma ratio in colon cancer: procedure and recommendations.

The tumor-stroma ratio (TSR) has been reported as a strong, independent prognostic parameter in colon cancer as well as in other epithelial cancer types, and may be implemented to routine pathology diagnostics. The TSR is an easy technique, based on routine hematoxylin and eosin stained histological sections, estimating the amount of stroma present in the primary tumor. It links tumors with high stromal content to poor prognosis. The analysis time is less than 2 min with a low inter-observer variation. Scoring of the TSR has been validated in a number of independent international studies. In this manuscript, we provide a detailed technical description of estimating the TSR in colon cancer, including examples, pitfalls, and recommendations.

Extracolonic cancer risk in Dutch patients with APC (adenomatous polyposis coli)-associated polyposis.

BACKGROUND: Screening of patients with familial adenomatous polyposis (FAP) have led to a substantial reduction in mortality due to colorectal cancer (CRC). Recent guidelines suggest that surveillance of non-intestinal malignancies should also be considered in those patients. However, the value of these surveillance programmes is unknown. The aims of this study were (1) to assess the occurrence of extracolonic malignancies in a large series of adenomatous polyposis coli (APC) mutation carriers and (2) to evaluate the causes of death. METHODS: All APC mutation carriers were selected from the Dutch polyposis registry. Data on causes of death were collected. Pathology reports were retrieved from the Dutch Pathology Registry. RESULTS: A total of 85 extracolonic malignancies were diagnosed in 74 of 582 APC mutation carriers. Duodenal and skin cancers were the most prevalent cancers. Thyroid cancer was observed in only 1.5% of the cases. The main cause of death was cancer (59% of all deaths), with 42% due to CRC and 21% due to duodenal cancer. One patient died from thyroid cancer. The second and third most common causes of death were cardiovascular disease (13% of all deaths) and desmoid tumours (11% of all deaths), respectively. CONCLUSION: Extending surveillance programmes to other cancers will not contribute significantly to the survival of patients with FAP.

Consequences of testing for mismatch repair deficiency of colorectal cancer in clinical practice.

INTRODUCTION: Mismatch repair deficiency (dMMR) can be found in Lynch syndrome (LS)-associated colorectal carcinoma and in 15% of sporadic colorectal cancer (CRC). Outcome of MMR-deficiency testing is important for surgical decisions as extended colectomy is recommended in young LS-patients with CRC. Moreover, the finding of a dMMR tumour has consequences for the choices of adjuvant chemotherapy as MMR-deficient CRC is resistant to 5-fluorouracil (5-FU) monotherapy. Aims of our study are to evaluate whether MMR-deficiency testing leads to (1) identification of LS, (2) change in surgical treatment and (3) adjustment of systemic therapy in patients with dMMR CRC. METHODS: We performed a multicentre, retrospective study, in a community hospital and a University Medical Centre. We included all CRC-patients between 2012 and 2016 who were tested for microsatellite instability. We collected clinical data such as gender, age, referral to clinical geneticist, surgical procedure and choice of chemotherapy. RESULTS: We analysed 225 CRCs. Twenty-four (10.7%) of 225 CRC were MMR-deficient. Of the 24 patients with dMMR CRC, 18 (75%) were referred to the clinical geneticist and in nine (37%) patients a MMR mutation was identified. In one (4%) of the 24 patients, a subtotal colectomy was performed. In seven (35%) out of 20 MMR deficient patients, the chemotherapy regimen was adjusted. CONCLUSIONS: The finding of a dMMR CRC had consequences for decisions on chemotherapy in a relative high proportion of patients. We recommend testing in all patients with CRC independent of age at diagnosis, as proper treatment decisions and genetic counselling are very important.

Practical guidance for mismatch repair-deficiency testing in endometrial cancer.

Background: Mismatch repair (MMR)-deficiency analysis is increasingly recommended for all endometrial cancers, as it identifies Lynch syndrome patients, and is emerging as a prognostic classifier to guide adjuvant treatment. The aim of this study was to define the optimal approach for MMR-deficiency testing and to clarify discrepancies between microsatellite instability (MSI) analysis and immunohistochemical (IHC) analysis of MMR protein expression. Patients and methods: Six hundred ninety- six endometrial cancers were analyzed for MSI (pentaplex panel) and MMR protein expression (IHC). Agreement between methodologies was calculated using Cohen's Kappa. MLH1 promoter hypermethylation, dinucleotide microsatellite markers and somatic MMR and POLE exonuclease domain (EDM) gene variants (using next-generation/Sanger sequencing) were analyzed in discordant cases. Results: MSI was found in 180 patients. Complete loss of expression of one or more MMR proteins was observed in 196 cases. A PMS2- and MSH6-antibody panel detected all cases with loss of MMR protein expression. The results of MSI and MMR protein expression were concordant in 655/696 cases (kappa = 0.854, P < 0.001). Ambiguous cases (n = 41, 6%) included: subclonal loss of MMR protein expression (n = 18), microsatellite stable or MSI-low cases with loss of MMR protein expression (n = 20), and MSI-low or MSI-high cases with retained MMR protein expression (n = 3). Most of these cases could be explained by MLH1 promoter hypermethylation. Five of seven cases with solitary loss of PMS2 or MSH6 protein expression carried somatic gene variants. Two MSI-high cases with retained MMR protein expression carried a POLE-EDM variant. Conclusion: MSI and IHC analysis are highly concordant in endometrial cancer. This holds true for cases with subclonal loss of MMR protein expression. Discordant MMR-proficient/MSI-high cases (<1%), may be explained by POLE-EDM variants.

Safety and efficacy of the addition of simvastatin to cetuximab in previously treated KRAS mutant metastatic colorectal cancer patients.

INTRODUCTION: Cetuximab is registered for use in colorectal cancer (CRC) patients with RAS wild-type tumours only. Simvastatin blocks the mevalonate pathway and thereby interferes with the post-translational modification (prenylation) of KRAS. We hypothesize that the activated KRAS pathway in KRAS mutant tumors can be inhibited by simvastatin rendering these tumors sensitive to the EGFR inhibitor cetuximab. METHODS: A Simon two-stage, single-arm, phase II study was performed to test the efficacy and safety of the addition of simvastatin to cetuximab in patients with a KRAS mutation in their CRC tumour who were previously treated with fluoropyrimidine, oxaliplatin and irinotecan based regimens. The primary endpoint was to test the percentage of patients alive and free from progression 12.5 weeks after the first administration of cetuximab. Our hypothesis was that at least 40% was free from progression, comparable to, though slightly lower than in KRAS wild-type patients. RESULTS: Four of 18 included patients (22.2%) were free from progression at the primary endpoint time. The time to progression in these 4 patients ranged from 20.3 to 47 weeks. CONCLUSION: Based on the current study we conclude that the theoretical concept of KRAS modulation with simvastatin was not applicable in the clinic, as we were not able to restore sensitivity to cetuximab in CRC patients harbouring a somatic KRAS mutation.

Beneficial Effects of the mTOR Inhibitor Everolimus in Patients with Advanced Medullary Thyroid Carcinoma: Subgroup Results of a Phase II Trial.

Objective. Until recently, advanced medullary thyroid cancer (MTC) had few treatment options except surgery. The mTOR inhibitor everolimus has shown encouraging results in neuroendocrine tumors. As part of a prospective phase II study, we analyzed the safety and efficacy of everolimus in advanced MTC. Methods. Seven patients with per RECIST 1.1 documented advanced MTC were included and received everolimus 10 mg daily. The primary objective was determining treatment efficacy. Secondary endpoints included progression-free survival (PFS), overall survival (OS), toxicity, and pharmacokinetics (PK). Results. Median follow-up duration was 28 weeks (17-147). Five patients (71%) showed SD, of which 4 (57%) showed SD >24 weeks. Median PFS and OS were 33 (95%CI: 8-56) and 30 (95%CI: 15-45) weeks, respectively. Toxicity was predominantly grade 1/2 and included mucositis (43%), fatigue (43%), and hypertriglyceridemia (43%). Four MTCs harbored the somatic RET mutation c.2753T>C, p.Met918Thr. The best clinical response was seen in a MEN2A patient. PK characteristics were consistent with phase I data. One patient exhibited extensive toxicity accompanying elevated everolimus plasma concentrations. Conclusions. This study suggests that everolimus exerts clinically relevant antitumor activity in patients with advanced MTC. Given the high level of clinical benefit and the relatively low toxicity profile, further investigation of everolimus in these patients is warranted.

The BMP pathway either enhances or inhibits the Wnt pathway depending on the SMAD4 and p53 status in CRC.

BACKGROUND: Constitutive Wnt activation is essential for colorectal cancer (CRC) initiation but also underlies the cancer stem cell phenotype, metastasis and chemosensitivity. Importantly Wnt activity is still modulated as evidenced by higher Wnt activity at the invasive front of clonal tumours termed the ß-catenin paradox. SMAD4 and p53 mutation status and the bone morphogenetic protein (BMP) pathway are known to affect Wnt activity. The combination of SMAD4 loss, p53 mutations and BMP signalling may integrate to influence Wnt signalling and explain the ß-catenin paradox. METHODS: We analysed the expression patterns of SMAD4, p53 and ß-catenin at the invasive front of CRCs using immunohistochemistry. We activated BMP signalling in CRC cells in vitro and measured BMP/Wnt activity using luciferase reporters. MTT assays were performed to study the effect of BMP signalling on CRC chemosensitivity. RESULTS: Eighty-four percent of CRCs with high nuclear ß-catenin staining are SMAD4 negative and/or p53 aberrant. BMP signalling inhibits Wnt signalling in CRC only when p53 and SMAD4 are unaffected. In the absence of SMAD4, BMP signalling activates Wnt signalling. When p53 is lost or mutated, BMP signalling no longer influences Wnt signalling. The cytotoxic effects of 5-FU are influenced in a similar manner. CONCLUSIONS: The BMP signalling pathway differentially modulates Wnt signalling dependent on the SMAD4 and p53 status. The use of BMPs in cancer therapy, as has been proposed by previous studies, should be targeted to individual cancers based on the mutational status of p53 and SMAD4.

Clinical prognostic value of combined analysis of Aldh1, Survivin, and EpCAM expression in colorectal cancer.

BACKGROUND: Tumour aggressiveness might be related to the degree of main cancer hallmark acquirement of tumour cells, reflected by expression levels of specific biomarkers. We investigated the expression of Aldh1, Survivin, and EpCAM, together reflecting main cancer hallmarks, in relation to clinical outcome of colorectal cancer (CRC) patients. METHODS: Immunohistochemistry was performed using a tumour tissue microarray of TNM (Tumour, Node, Metastasis)-stage I-IV CRC tissues. Single-marker expression or their combination was assessed for associations with the clinical outcome of CRC patients (N=309). RESULTS: Increased expression of Aldh1 or Survivin, or decreased expression of EpCAM was each associated with poor clinical outcome, and was therefore identified as clinically unfavourable expression. Analyses of the combination of all three markers showed worse clinical outcome, specifically in colon cancer patients, with an increasing number of markers showing unfavourable expression. Hazard ratios ranged up to 8.3 for overall survival (P<0.001), 36.6 for disease-specific survival (P<0.001), and 27.1 for distant recurrence-free survival (P<0.001). CONCLUSIONS: Our data identified combined expression levels of Aldh1, Survivin, and EpCAM as strong independent prognostic factors, with high hazard ratios, for survival and tumour recurrence in colon cancer patients, and therefore reflect tumour aggressiveness.

Reduced expression of bone morphogenetic protein receptor IA in pancreatic cancer is associated with a poor prognosis.

BACKGROUND: The expression of SMAD4, the central component of the transforming growth factor-ß (TGF-ß) and bone morphogenetic protein (BMP) signalling pathways, is lost in 50% of pancreatic cancers and is associated with a poor survival. Although the TGF-ß pathway has been extensively studied and characterised in pancreatic cancer, there is very limited data on BMP signalling, a well-known tumour-suppressor pathway. BMP signalling can be lost not only at the level of SMAD4 but also at the level of BMP receptors (BMPRs), as has been described in colorectal cancer. METHODS: We performed immunohistochemical analysis of the expression levels of BMP signalling components in pancreatic cancer and correlated these with survival. We also manipulated the activity of BMP signalling in vitro. RESULTS: Reduced expression of BMPRIA is associated with a significantly worse survival, primarily in a subset of SMAD4-positive cancers. In vitro inactivation of SMAD4-dependent BMP signalling increases proliferation and invasion of pancreatic cancer cells, whereas inactivation of BMP signalling in SMAD4-negative cells does not change the proliferation and invasion or leads to an opposite effect. CONCLUSION: Our data suggest that BMPRIA expression is a good prognostic marker and that the BMP pathway is a potential target for future therapeutic interventions in pancreatic cancer.

Long-term analysis of the efficacy and tolerability of sorafenib in advanced radio-iodine refractory differentiated thyroid carcinoma: final results of a phase II trial.

OBJECTIVE: We conducted a prospective phase II clinical trial to determine the efficacy of sorafenib in patients with advanced radio-iodine refractory differentiated thyroid cancer. In this article, the long-term results are presented. PATIENTS AND METHODS: Thirty-one patients with progressive metastatic or locally advanced radioactive iodine refractory differentiated thyroid cancer received sorafenib 400 mg orally twice daily. The study end points included response rate, progression-free survival (PFS), overall survival (OS), best response by Response Evaluation Criteria in Solid Tumors criteria 1.0, and toxicity. RESULTS: Median PFS was 18 months (95% confidence interval (95% CI): 7-29 months) and median OS was 34.5 months (95% CI: 19-50 months). Eight patients (31%) achieved a partial response and 11 patients (42%) showed stable disease after a median follow-up of 25 months (range 3.5-39 months). Toxicity mostly included hand foot syndrome, weight loss, diarrhea, and rash. CONCLUSION: Sorafenib has clinically relevant antitumor activity in patients with progressive metastatic or locally advanced radio-iodine refractory differentiated thyroid cancer. Sorafenib can nowadays be considered as the standard option in these patients.

New treatment modalities in advanced thyroid cancer.

BACKGROUND: Thyroid cancer is a heterogeneous disease that is classified into differentiated thyroid carcinoma (DTC), undifferentiated/anaplastic thyroid carcinoma (ATC) and medullary thyroid carcinoma. Results of conventional treatment modalities in advanced thyroid cancer have been disappointing and therefore, new therapies are needed. METHODS: We searched PubMed, The Cochrane Library, Medline and EMBASE databases and abstracts published in annual proceedings for new treatment modalities in advanced thyroid cancer. We also searched for ongoing trials in www.clinicaltrials.gov. RESULTS: Six phase I, 17 phase II and 1 phase III trials with tyrosine kinase inhibitors were carried out. We found 2 pilot studies and 11 phase II trials with redifferentiation therapies, mainly in DTC. For antiproliferative approaches, three phase I and four phase II trials were found. Immunomodulatory gene therapy was tested in a pilot study in ATC patients. Two phase II trials were carried out with immunotherapy. One phase I and nine phase II trials were found with radionucleotide therapy in patients with DTC. CONCLUSION: The developments in the treatment of advanced thyroid cancer are intriguing. Future trials should aim at combinations of targeted agents with or without other treatment modalities, and will hopefully contribute to further improvement of outcomes.

Increased frequency of 20q gain and copy-neutral loss of heterozygosity in mismatch repair proficient familial colorectal carcinomas.

Many hereditary nonpolyposis colorectal cancers (CRCs) cannot be explained by Lynch syndrome. Other high penetrance genetic risk factors are likely to play a role in these mismatch repair (MMR)-proficient CRC families. Because genomic profiles of CRC tend to vary with CRC susceptibility syndromes, our aim is to analyze the genomic profile of MMR-proficient familial CRC to obtain insight into the biological basis of MMR-proficient familial CRC. We studied 30 MMR-proficient familial colorectal carcinomas, from 15 families, for genomic aberrations, including gains, physical losses, and copy-neutral loss of heterozygosity LOH (cnLOH) using SNP array comparative genomic hybridization. In addition, we performed somatic mutation analysis for KRAS, BRAF, PIK3CA and GNAS. The frequency of 20q gain (77%) is remarkably increased when compared with sporadic CRC, suggesting that 20q gain is involved in tumor progression of familial CRC. There is also a significant increase in the frequency of cnLOH and, as a consequence, a reduced frequency of physical loss compared with sporadic CRC. The most frequent aberrations observed included gains of 7p, 7q, 8q, 13q, 20p and 20q as well as physical losses of 17p, 18p and 18q. Most of these changes are also observed in sporadic CRC. Mutations in KRAS were identified in 37% of the MMR-proficient CRCs, and mutations in BRAF were identified in 16%. No mutations were identified in PIK3CA or chromosome 20 candidate gene GNAS. We show that the patterns of chromosomal instability of MMR-proficient familial CRC are clearly distinct from those from sporadic CRC. Both the increased gain on chromosome 20 and the increased levels of cnLOH suggest the presence of yet undiscovered germline defects that can, in part, underlie the cancer risk in these families.

PTEN in colorectal cancer: a report on two Cowden syndrome patients.

Heterozygous germline PTEN mutations cause Cowden syndrome. The risk of colorectal cancer in Cowden patients, however, remains a matter of debate. We describe two patients presenting with colorectal cancer at a young age (28 and 39 years) and dysmorphisms fitting the Cowden spectrum. Heterozygous germline mutations in PTEN were found in both patients. Moreover, analysis of the resected colorectal cancer specimens revealed loss of heterozygosity at the PTEN locus with retention of the mutated alleles, and greatly reduced or absent PTEN expression. Histologically and molecularly, the tumours showed resemblance with sporadic colorectal cancers, although they had prominent fibrotic stroma. Our data indicate that PTEN loss was involved in carcinogenesis in the two patients, supporting that colorectal cancer is part of the Cowden syndrome-spectrum. This is in line with data on sporadic colorectal cancer, mice studies and emerging epidemiological data on Cowden syndrome. Although the exact role of germline PTEN mutations in the carcinogenesis of colorectal cancer remains unclear, we think that Cowden syndrome should be in the differential diagnosis of colorectal cancer certainly in view of the possible prognostic and therapeutic consequences. Prospective follow-up and surveillance of PTEN mutation carriers from the age of 25 to 30 years in a study setting should clarify this issue.

Molecular alterations associated with liver metastases development in colorectal cancer patients.

BACKGROUND: Understanding the molecular biology of colorectal cancer (CRC) provides opportunities for effective personalised patient management. We evaluated whether chromosomal aberrations, mutations in the PI(3)K signalling pathway and the CpG-island methylator phenotype (CIMP) in primary colorectal tumours can predict liver metastases. METHODS: Formalin-fixed paraffin-embedded material from primary colorectal tumours of three different groups were investigated: patients with CRC without metastases (M0, n=39), patients who were treated with hyperthermal intraperitoneal chemotherapy for CRC metastases confined to the peritoneum (PM, n=46) and those who had isolated hepatic perfusion for CRC metastases confined to the liver (LM, n=48). RESULTS: All samples were analysed for DNA copy number changes, PIK3CA, KRAS, BRAF mutations, CIMP and microsatellite instability. The primary CRCs of the LM group had significantly higher frequency of amplified chromosome 20q (P=0.003), significantly fewer mutations in the PI(3)K signalling pathway (P=0.003) and fewer CIMP high tumours (P=0.05). There was a strong inverse correlation between 20q and the PI(3)K pathway mutations. CONCLUSION: The development of CRC liver metastases is associated with amplification of chromosome 20q and not driven by mutations in the PI(3)K signalling pathway.

High detection rate of adenomas in familial colorectal cancer.

BACKGROUND AND AIMS: Subjects with one first-degree relative (FDR) with colorectal cancer (CRC) <50 years old or two FDRs with CRC have an increased risk for CRC (RR 4-6). Current guidelines recommend colonoscopic surveillance of such families. However, information about the yield of surveillance is limited. The aim of the present study was to evaluate the outcome of surveillance and to identify risk factors for the development of adenomas. PATIENTS AND METHODS: Subjects were included if they fulfilled the following criteria: asymptomatic subjects aged between 45 and 65 years, with one FDR with CRC <50 years old (group A) or two FDRs with CRC diagnosed at any age (group B). Subjects with a personal history of inflammatory bowel disease or colorectal surgery were excluded. RESULTS: A total of 551 subjects (242 male) met the selection criteria. Ninety-five subjects with a previous colonoscopy were excluded. Two of 456 remaining subjects (0.4%) were found to have a colorectal tumour (one CRC and one carcinoid). Adenomas were detected in 85 (18.6%) and adenomas with advanced pathology in 37 subjects (8.1%). 30 subjects (6.6%) had multiple (>1) adenomas. Men were more often found to have an adenoma than women (24% vs 14.3%; p=0.01). Adenomas were more frequent in group B compared with group A (22.0% vs 15.6%; p=0.09). CONCLUSION: The yield of colonoscopic surveillance in familial CRC is substantially higher than the yield of screening reported for the general population.

COGENT (COlorectal cancer GENeTics): an international consortium to study the role of polymorphic variation on the risk of colorectal cancer.

It is now recognised that a part of the inherited risk of colorectal cancer (CRC) can be explained by the co-inheritance of low-penetrance genetic variants. The accumulated experience to date in identifying these variants has served to highlight difficulties in conducting statistically and methodologically rigorous studies and follow-up analyses. The COGENT (COlorectal cancer GENeTics) consortium includes 20 research groups in Europe, Australia, the Americas, China and Japan. The overarching goal of COGENT is to identify and characterise low-penetrance susceptibility variants for CRC through association-based analyses. In this study, we review the rationale for identifying low-penetrance variants for CRC and our proposed strategy for establishing COGENT.