Accuracy of colon capsule endoscopy in detecting colorectal polyps in individuals with familial colorectal cancer: could we avoid colonoscopies?

Background. Individuals with a family history of colorectal cancer (CRC) have an increased risk of CRC. We evaluated the diagnostic yield of CCE in the detection of lesions and also two different colon preparations. Methods. A prospective multicenter study was designed to assess CCE diagnostic yield in a cohort of asymptomatic individuals with a family history of CRC. CCE and colonoscopy were performed on the same day by 2 endoscopists who were blinded to the results of the other procedure. Results. Fifty-three participants were enrolled. The sensitivity, specificity, PPV, and NPV of CCE for detecting advanced adenomas were 100%, 98%, 67%, and 100%. Sensitivity, specificity, PPV, and NPV of CCE for the diagnosis of individuals with polyps were 87%, 97%, 93%, and 88%, respectively. CCE identify 100% of individuals with significant or advanced lesions. Overall cleanliness was adequate by 60.7% of them. The PEG-ascorbic boost seems to improve colon cleanliness, with similar colonic transit time. Conclusion. CCE is a promising tool, but it has to be considered as an alternative technique in this population in order to reduce the number of colonoscopies performed. More studies are needed to understand appropriate screening follow-up intervals and optimize the bowel preparation regimen

Exome sequencing of early-onset patients supports genetic heterogeneity in colorectal cancer

Colorectal cancer (CRC) is a complex disease that can be caused by a spectrum of genetic variants ranging from low to high penetrance changes, that interact with the environment to determine which individuals will develop the disease. In this study, we sequenced 20 early-onset CRC patients to discover novel genetic variants that could be linked to the prompt disease development. Eight genes, CHAD, CHD1L, ERCC6, IGTB7, PTPN13, SPATA20, TDG and TGS1, were selected and re-sequenced in a further 304 early onset CRC patients to search for rare, high-impact variants. Although we found a recurring truncating variant in the TDG gene shared by two independent patients, the results obtained did not help consolidate any of the candidates as promising CRC predisposing genes. However, we found that potential risk alleles in our extended list of candidate variants have a tendency to appear at higher numbers in younger cases. This supports the idea that CRC onset may be oligogenic in nature and may show molecular heterogeneity. Further, larger and robust studies are thus needed to unravel the genetics behind early-onset CRC development, coupled with novel functional analyses and omic approaches that may offer complementary insight

Multiple sporadic colorectal cancers display a unique methylation phenotype.

Epigenetics are thought to play a major role in the carcinogenesis of multiple sporadic colorectal cancers (CRC). Previous studies have suggested concordant DNA hypermethylation between tumor pairs. However, only a few methylation markers have been analyzed. This study was aimed at describing the epigenetic signature of multiple CRC using a genome-scale DNA methylation profiling. We analyzed 12 patients with synchronous CRC and 29 age-, sex-, and tumor location-paired patients with solitary tumors from the EPICOLON II cohort. DNA methylation profiling was performed using the Illumina Infinium HM27 DNA methylation assay. The most significant results were validated by Methylight. Tumors samples were also analyzed for the CpG Island Methylator Phenotype (CIMP); KRAS and BRAF mutations and mismatch repair deficiency status. Functional annotation clustering was performed. We identified 102 CpG sites that showed significant DNA hypermethylation in multiple tumors with respect to the solitary counterparts (difference in β value ≥0.1). Methylight assays validated the results for 4 selected genes (p = 0.0002). Eight out of 12(66.6%) multiple tumors were classified as CIMP-high, as compared to 5 out of 29(17.2%) solitary tumors (p = 0.004). Interestingly, 76 out of the 102 (74.5%) hypermethylated CpG sites found in multiple tumors were also seen in CIMP-high tumors. Functional analysis of hypermethylated genes found in multiple tumors showed enrichment of genes involved in different tumorigenic functions. In conclusion, multiple CRC are associated with a distinct methylation phenotype, with a close association between tumor multiplicity and CIMP-high. Our results may be important to unravel the underlying mechanism of tumor multiplicity

Effect of oral anticoagulants on the outcome of faecal immunochemical test

Background: We aimed to evaluate whether oral anticoagulants (OACs) alter faecal immunochemical test (FIT) performance in average-risk colorectal cancer (CRC) screening. Methods: Individuals aged 50-69 years were invited to receive one FIT sample (cutoff 75 ng ml-1) between November 2008 and June 2011. Results: Faecal immunochemical test was positive in 9.3% (21 out of 224) of users of OAC and 6.2% (365 out of 5821) of non-users (P-trend ¼ 0.07). The positive predictive value (PPV) for advanced neoplasia (AN) in non-users was 50.4% vs 47.6% in users (odds ratio, 0.70; 95% CI, 0.3-1.8; P ¼ 0.5). The PPV for AN in OAC more antiplatelets (aspirin or clopidogrel) was 75% (odds ratio, 2; 95% CI, 0.4-10.8; P ¼ 0.4). Conclusions: Oral anticoagulant did not significantly modify the PPV for AN in this population-based colorectal screening program. The detection rate of advanced adenoma was higher in the combination OAC more antiplatelets

New genes emerging for colorectal cancer predisposition.

Colorectal cancer (CRC) is one of the most frequent neoplasms and an important cause of mortality in the developed world. This cancer is caused by both genetic and environmental factors although 35% of the variation in CRC susceptibility involves inherited genetic differences. Mendelian syndromes account for about 5% of the total burden of CRC, with Lynch syndrome and familial adenomatous polyposis the most common forms. Excluding hereditary forms, there is an important fraction of CRC cases that present familial aggregation for the disease with an unknown germline genetic cause. CRC can be also considered as a complex disease taking into account the common disease-commom variant hypothesis with a polygenic model of inheritance where the genetic components of common complex diseases correspond mostly to variants of low/moderate effect. So far, 30 common, low-penetrance susceptibility variants have been identified for CRC. Recently, new sequencing technologies including exome- and whole-genome sequencing have permitted to add a new approach to facilitate the identification of new genes responsible for human disease predisposition. By using whole-genome sequencing, germline mutations in the POLE and POLD1 genes have been found to be responsible for a new form of CRC genetic predisposition called polymerase proofreading-associated polyposis

Interacció leucòcit-endoteli i mobilització de cèl·lules neoplàsiques en el càncer colorectal

[cat] El procés de disseminació metastàsic en el càncer colorectal és un procés complex multifactorial. La present tesi ha pretès aprofundir en dos aspectes: els mecanismes de defensa immunològic a través de la caracterització dels fenòmens de interacció leucocitària, i el procés de mobilització tumoral a través de la detecció i pronòstic de les cèl·lules neoplàsiques circulants.En la present tesi s'ha confirmat que existeix una deficient interacció dels leucòcits circulants amb l'endoteli dels vasos tumorals respecte a l'endoteli no tumoral, tant de rodament en condicions basals com d'adhesió rere l'administració d'un estímul inflamatori. S'ha demostrat que la molècula implicada en els fenòmens d'adhesió leucocitària es ICAM-1, ja que el seu immunobloqueig reverteix els fenòmens d'adhesió induïts per LPS. S'ha demostrat a través de la tècnica del doble marcatge amb anticossos que la deficient interacció leucòcit-endoteli a nivell tumoral no pot atribuir-se a una menor expressió de les diferents molècules d'adhesió implicades en aquest fenomen. Al intentar avaluar els mecanismes responsables de la deficient interacció leucòcit endoteli es va descartar la participació de l'antigen carcinoembrionari, els productes derivats de la ciclooxigenasa i la sintasa induïble de l'òxid nítric. No obstant es va demostrar que la inhibició no selectiva de la sintasa de l'òxid nítric augmentava de manera dosi-depenent el rodament leucocitari i l'adhesió post-LPS a nivell del teixit tumoral. Efecte similar es va observar al procedir al immunobloqueig del factor transformant B1. Per tant, dels resultats obtinguts, es pot ressaltar que tant l'òxid nítric com el factor de creixement transformant B1 participen, al menys de manera parcial, en els fenòmens d'escapament dels sistemes de immunovigilància a nivell tumoral.La segona part de la tesi doctoral ha confirmat en primer lloc que es possible detectar la existència de cèl·lules neoplàsiques circulants en sang perifèrica de malalts amb càncer colorectal a través de la detecció de RNA missatger de l'antigen carcinoembrionari. Aquesta tècnica s'ha confirmat sensible (detecta una cèl·lula neoplàsica per cada 107 leucòcits) i específica (negativa en els controls sans). Emprat aquesta tècnica s'ha intentat avaluar un dels aspectes més controvertits de la cirurgia laparoscòpica en el càncer colorectal, la disseminació tumoral. Mitjançant estudis de detecció de cèl·lules neoplàsiques circulants en sang perifèrica, portal i en el líquid peritoneal, s'ha descartat el potencial efecte deleteri atribuït a la cirurgia laparoscòpica. No es varen observar diferències significatives entre el grup de cirurgia convencional respecte al grup de cirurgia laparoscòpica, en el número de pacients amb determinacions positives en els tres territoris avaluats rere la resecció quirúrgica . Finalment, es va intentar establir la significació pronòstica de la detecció de cèl·lules neoplàsiques circulants en pacients amb càncer colorectal mitjançant el seu seguiment a llarg termini. Tant en el grup global de pacients amb càncer colorectal com en aquells en els que s'havia realitzat una resecció curativa , la determinació preoperatòria de cèl·lules circulants no s'associava a un pitjor pronòstic a llarg termini (supervivència global i supervivència lliure de malaltia). Tenint en compte que estudis previs havien demostrat que la cirurgia afavoria la mobilització de cèl·lules neoplàsiques en el càncer colorectal, es va valorar la significació pronòstica de la detecció de cèl.lules neoplàsiques a les 24 hores de la cirurgia. Novament, la detecció postoperatòria no s'associava a un pitjor pronòstic a llarg termini

Multiple sporadic colorectal cancers display a unique methylation phenotype.

Epigenetics are thought to play a major role in the carcinogenesis of multiple sporadic colorectal cancers (CRC). Previous studies have suggested concordant DNA hypermethylation between tumor pairs. However, only a few methylation markers have been analyzed. This study was aimed at describing the epigenetic signature of multiple CRC using a genome-scale DNA methylation profiling. We analyzed 12 patients with synchronous CRC and 29 age-, sex-, and tumor location-paired patients with solitary tumors from the EPICOLON II cohort. DNA methylation profiling was performed using the Illumina Infinium HM27 DNA methylation assay. The most significant results were validated by Methylight. Tumors samples were also analyzed for the CpG Island Methylator Phenotype (CIMP); KRAS and BRAF mutations and mismatch repair deficiency status. Functional annotation clustering was performed. We identified 102 CpG sites that showed significant DNA hypermethylation in multiple tumors with respect to the solitary counterparts (difference in β value ≥0.1). Methylight assays validated the results for 4 selected genes (p = 0.0002). Eight out of 12(66.6%) multiple tumors were classified as CIMP-high, as compared to 5 out of 29(17.2%) solitary tumors (p = 0.004). Interestingly, 76 out of the 102 (74.5%) hypermethylated CpG sites found in multiple tumors were also seen in CIMP-high tumors. Functional analysis of hypermethylated genes found in multiple tumors showed enrichment of genes involved in different tumorigenic functions. In conclusion, multiple CRC are associated with a distinct methylation phenotype, with a close association between tumor multiplicity and CIMP-high. Our results may be important to unravel the underlying mechanism of tumor multiplicity

Effect of oral anticoagulants on the outcome of faecal immunochemical test

Background: We aimed to evaluate whether oral anticoagulants (OACs) alter faecal immunochemical test (FIT) performance in average-risk colorectal cancer (CRC) screening. Methods: Individuals aged 50-69 years were invited to receive one FIT sample (cutoff 75 ng ml-1) between November 2008 and June 2011. Results: Faecal immunochemical test was positive in 9.3% (21 out of 224) of users of OAC and 6.2% (365 out of 5821) of non-users (P-trend ¼ 0.07). The positive predictive value (PPV) for advanced neoplasia (AN) in non-users was 50.4% vs 47.6% in users (odds ratio, 0.70; 95% CI, 0.3-1.8; P ¼ 0.5). The PPV for AN in OAC more antiplatelets (aspirin or clopidogrel) was 75% (odds ratio, 2; 95% CI, 0.4-10.8; P ¼ 0.4). Conclusions: Oral anticoagulant did not significantly modify the PPV for AN in this population-based colorectal screening program. The detection rate of advanced adenoma was higher in the combination OAC more antiplatelets