Germ-line mutations in the exonuclease domains of POLE and POLD1 have been recently associated with polyposis and colorectal cancer (CRC) predisposition. Here, we aimed to gain a better understanding ...of the phenotypic characteristics of this syndrome to establish specific criteria for POLE and POLD1 mutation screening and to help define the clinical management of mutation carriers.
The exonuclease domains of POLE and POLD1 were studied in 529 kindred, 441 with familial nonpolyposis CRC and 88 with polyposis, by using pooled DNA amplification and massively parallel sequencing.
Seven novel or rare genetic variants were identified. In addition to the POLE p.L424V recurrent mutation in a patient with polyposis, CRC and oligodendroglioma, six novel or rare POLD1 variants (four of them, p.D316H, p.D316G, p.R409W, and p.L474P, with strong evidence for pathogenicity) were identified in nonpolyposis CRC families. Phenotypic data from these and previously reported POLE/POLD1 carriers point to an associated phenotype characterized by attenuated or oligo-adenomatous colorectal polyposis, CRC, and probably brain tumors. In addition, POLD1 mutations predispose to endometrial and breast tumors.
Our results widen the phenotypic spectrum of the POLE/POLD1-associated syndrome and identify novel pathogenic variants. We propose guidelines for genetic testing and surveillance recommendations.
Guidelines recommend routine screening for colorectal cancer (CRC) in asymptomatic adults starting at age 50. The most extensively used noninvasive test for CRC screening is the fecal immunochemical ...test (FIT), which has an overall sensitivity for CRC of approximately 61.0%-91.0%, which drops to 27.0%-67.0% for advanced adenomas. These figures contain a high false-positive rate and a low positive predictive value. This work aimed to develop a new, noninvasive CRC screening tool based on fecal bacterial markers capable of decreasing FIT false-positive rates in a FIT-positive population. We defined a fecal bacterial signature (RAID-CRC Screen) in a proof-of-concept with 172 FIT-positive individuals and validated the obtained results on an external cohort of 327 FIT-positive subjects. All study participants had joined the national CRC screening program. In the clinical validation of RAID-CRC Screen, a sensitivity of 83.9% and a specificity of 16.3% were obtained for the detection of advanced neoplasm lesions (advanced adenomas and/or CRC). FIT 20 μg/g produced 184 false-positive results. Using RAID-CRC Screen, this value was reduced to 154, thus reducing the false-positive rate by 16.3%. The RAID-CRC Screen test could be implemented in CRC screening programs to allow a significant reduction in the number of colonoscopies performed unnecessarily for FIT-positive participants of CRC screening programs.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The ALFRED (Allelic Loss Featuring Rare Damaging) in silico method was developed to identify cancer predisposition genes through the identification of somatic second hits. By applying ALFRED to ...~10,000 tumor exomes, 49 candidate genes were identified. We aimed to assess the causal association of the identified genes with colorectal cancer (CRC) predisposition. Of the 49 genes,
,
,
,
and
were selected based on specific criteria relevant for hereditary CRC genes. Gene sequencing was performed in 736 patients with familial/early onset CRC or polyposis without germline pathogenic variants in known genes. Twelve (predicted) damaging variants in 18 patients were identified. A gene-based burden test in 1596 familial/early-onset CRC patients, 271 polyposis patients, 543 TCGA CRC patients and >134,000 controls (gnomAD, non-cancer), revealed no clear association with CRC for any of the studied genes. Nevertheless, (non-significant) over-representation of disruptive variants in
,
and
in CRC patients compared to controls was observed. A somatic second hit was identified in one of 20 tumors tested, corresponding to an
carrier. In conclusion, most genes identified through the ALFRED in silico method were not relevant for CRC predisposition, although a possible association was detected for
,
and
.
A large proportion of familial and/or early-onset cancer patients do not carry pathogenic variants in known cancer predisposing genes. We aimed to assess the contribution of previously validated ...low-risk colorectal cancer (CRC) alleles to familial/early-onset CRC (fCRC) and to serrated polyposis. We estimated the association of CRC with a 92-variant-based weighted polygenic risk score (wPRS) using 417 fCRC patients, 80 serrated polyposis patients, 1077 hospital-based incident CRC patients, and 1642 controls. The mean wPRS was significantly higher in fCRC than in controls or sporadic CRC patients. fCRC patients in the highest (20th) wPRS quantile were at four-fold greater CRC risk than those in the middle quantile (10th). Compared to low-wPRS fCRC, a higher number of high-wPRS fCRC patients had developed multiple primary CRCs, had CRC family history, and were diagnosed at age ≥50. No association with wPRS was observed for serrated polyposis. In conclusion, a relevant proportion of mismatch repair (MMR)-proficient fCRC cases might be explained by the accumulation of low-risk CRC alleles. Validation in independent cohorts and development of predictive models that include polygenic risk score (PRS) data and other CRC predisposing factors will determine the implementation of PRS into genetic testing and counselling in familial and early-onset CRC.
The cancer-predisposing syndrome caused by biallelic mutations in NTHL1 may not be a solely colorectal cancer (CRC) and polyposis syndrome but rather a multi-tumor recessive disease. The presence of ...≤10 adenomas in several mutation carriers suggests a possible causal role of NTHL1 in hereditary or early-onset nonpolyposis CRC. The involvement of NTHL1 in serrated/hyperplastic polyposis remains unexplored. The aim of our study is to elucidate the role of NTHL1 in the predisposition to personal or familial history of multiple tumor types, familial/early-onset nonpolyposis CRC, and serrated polyposis. NTHL1 mutational screening was performed in 312 cancer patients with personal or family history of multiple tumor types, 488 with hereditary nonpolyposis CRC, and 96 with serrated/hyperplastic polyposis. While no biallelic mutation carriers were identified in patients with personal and/or family history of multiple tumor types or with serrated polyposis, one was identified among the 488 nonpolyposis CRC patients. The carrier of c.268C>T (p.Q90*) and 550-1G>A was diagnosed with CRC and meningioma at ages 37 and 45 respectively, being reclassified as attenuated adenomatous polyposis after the cumulative detection of 26 adenomas. Our findings suggest that biallelic mutations in NTHL1 rarely cause CRC, a personal/familial multi-tumor history, or serrated polyposis, in absence of adenomas.
Faecal immunochemical test (FIT) has been recommended to assess symptomatic patients for colorectal cancer (CRC) detection. Nevertheless, some conditions could theoretically favour blood originating ...in proximal areas of the gastrointestinal tract passing through the colon unmetabolized. A positive FIT result could be related to other gastrointestinal cancers (GIC).
To assess the risk of GIC detection and related death in FIT-positive symptomatic patients (threshold 10 μg Hb/g faeces) without CRC.
Post hoc cohort analysis performed within two prospective diagnostic test studies evaluating the diagnostic accuracy of different FIT analytical systems for CRC and significant colonic lesion detection. Ambulatory patients with gastrointestinal symptoms referred consecutively for colonoscopy from primary and secondary healthcare, underwent a quantitative FIT before undergoing a complete colonoscopy. Patients without CRC were divided into two groups (positive and negative FIT) using the threshold of 10 μg Hb/g of faeces and data from follow-up were retrieved from electronic medical records of the public hospitals involved in the research. We determined the cumulative risk of GIC, CRC and upper GIC. Hazard rate (HR) was calculated adjusted by age, sex and presence of significant colonic lesion.
We included 2709 patients without CRC and a complete baseline colonoscopy, 730 (26.9%) with FIT ≥ 10 µgr Hb/gr. During a mean time of 45.5 ± 20.0 mo, a GIC was detected in 57 (2.1%) patients: An upper GIC in 35 (1.3%) and a CRC in 14 (0.5%). Thirty-six patients (1.3%) died due to GIC: 22 (0.8%) due to an upper GIC and 9 (0.3%) due to CRC. FIT-positive subjects showed a higher CRC risk (HR 3.8, 95%CI: 1.2-11.9) with no differences in GIC (HR 1.5, 95%CI: 0.8-2.7) or upper GIC risk (HR 1.0, 95%CI: 0.5-2.2). Patients with a positive FIT had only an increased risk of CRC-related death (HR 10.8, 95%CI: 2.1-57.1) and GIC-related death (HR 2.2, 95%CI: 1.1-4.3), with no differences in upper GIC-related death (HR 1.4, 95%CI: 0.6-3.3). An upper GIC was detected in 22 (0.8%) patients during the first year. Two variables were independently associated: anaemia (OR 5.6, 95%CI: 2.2-13.9) and age ≥ 70 years (OR 2.7, 95%CI: 1.1-7.0).
Symptomatic patients without CRC have a moderate risk increase in upper GIC, regardless of the FIT result. Patients with a positive FIT have an increased risk of post-colonoscopy CRC.
Background & Aims We investigated whether patients with multiple serrated polyps, but not meeting the World Health Organization criteria for serrated polyposis syndrome, and their relatives have ...similar risks for colorectal cancer (CRC) as those diagnosed with serrated polyposis. Methods We collected data from patients with more than 10 colonic polyps, recruited in 2008–2009 from 24 hospitals in Spain for a study of causes of multiple colonic polyps. We analyzed data from 53 patients who met the criteria for serrated polyposis and 145 patients who did not meet these criteria, but who had more than 10 polyps throughout the colon, of which more than 50% were serrated. We calculated age- and sex-adjusted standardized incidence ratios (SIRs) for CRC in both groups, as well as in their first-degree relatives. Results The prevalence of CRC was similar between patients with confirmed serrated polyposis and multiple serrated polyps (odds ratio, 1.35; 95% confidence interval CI, 0.64–2.82; P = .40). The SIR for CRC in patients with serrated polyposis (0.51; 95% CI, 0.01–2.82) did not differ significantly from the SIR for CRC in patients with multiple serrated polyps (0.74; 95% CI, 0.20–1.90; P = .70). The SIR for CRC also did not differ significantly between first-degree relatives of these groups (serrated polyposis: 3.28, 95% CI, 2.16–4.77; multiple serrated polyps: 2.79, 95% CI, 2.10–3.63; P = .50). Kaplan–Meier analysis showed no differences in the incidence of CRC between groups during the follow-up period (log-rank, 0.6). Conclusions The risk of CRC in patients with multiple serrated polyps who do not meet the criteria for serrated polyposis, and in their first-degree relatives, is similar to that of patients diagnosed with serrated polyposis.
Summary
Background
Colorectal cancer is the second commonest cause of cancer mortality. Some countries are implementing colorectal cancer screening to detect lesions at an early stage using ...non‐invasive tools like the faecal immunochemical test. Despite affordability, this test shows a low sensitivity for precancerous lesions and a low positive predictive value for colorectal cancer, resulting in a high false‐positive rate.
Aim
To develop a new, non‐invasive colorectal cancer screening tool based on bacterial faecal biomarkers, which in combination with the faecal immunochemical test, could allow a reduction in the false‐positive rate. This tool is called risk assessment of intestinal disease for colorectal cancer (RAID‐CRC).
Methods
We performed both the faecal immunochemical test and the bacterial markers analysis (RAID‐CRC test) in stool samples from individuals with normal colonoscopy (167), non‐advanced adenomas (88), advanced adenomas (30) and colorectal cancer (48). All the participants showed colorectal cancer‐associated symptoms.
Results
Performance of the faecal immunochemical test for advanced neoplasia (ie advanced adenoma and colorectal cancer) was determined by using the cut‐off value established in Catalonia (20 µg haemoglobin/g of faeces) for a population‐based screening approach. Sensitivity and specificity values of 83% and 80%, respectively, and positive and negative predictive values of 56% and 94%, respectively, were obtained. When both the immunological and the biological analysis were combined, the corresponding values were 80% and 90% for sensitivity and specificity, respectively, and 70% and 94% for positive and negative predictive values, respectively, resulting in a 50% reduction of the false‐positive rate.
Conclusions
RAID‐CRC test allows a substantial reduction in the faecal immunochemical test false‐positive results (50%) in a symptomatic population. Further validation is indicated in a colorectal cancer‐screening scenario.
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