BRAF V600E mutations have been reported as a marker of sporadic microsatellite instability (MSI) colorectal cancer (CRC). Current international diagnostic guidelines recommend BRAF mutation testing ...in MSI CRC patients to predict low risk of Lynch syndrome (LS). We evaluated the age‐specific performance of BRAF testing in LS diagnostics. We systematically compared the prevalence of BRAF mutations in LS‐associated CRCs and unselected MSI CRCs in different age groups as available from published studies, databases and population‐based patient cohorts. Sensitivity/specificity analysis of BRAF testing for exclusion of LS and cost calculations were performed. Among 969 MSI CRCs from LS carriers in the literature and German HNPCC Consortium, 15 (1.6%) harbored BRAF mutations. Six of seven LS patients with BRAF‐mutant CRC and reported age were <50 years. Among 339 of 756 (44.8%) of BRAF mutations detected in unselected MSI CRC, only 2 of 339 (0.6%) BRAF mutations were detected in patients <50 years. The inclusion of BRAF testing led to high risk of missing LS patients and increased costs at age <50 years. BRAF testing in patients <50 years carries a high risk of missing a hereditary cancer predisposition and is cost‐inefficient. We suggest direct referral of MSI CRC patients <50 years to genetic counseling without BRAF testing.
What's new?
Lynch syndrome (LS) is the most common hereditary colorectal cancer. While these cancers usually show microsatellite instability (MSI), most MSI tumors are sporadic. Here, the authors evaluated the usefulness of testing for BRAF mutations as a way to distinguish LS cancers from sporadic cases. They found that the frequency of tumors carrying BRAF mutations in LS patients under age 50 is very similar to the frequency of those mutations in MSI cancers from that age group, suggesting that there's substantial overlap between the two groups. Thus, BRAF mutation status should not be used to exclude LS in patients under 50.
Approximately 25-30% of colorectal cancer (CRC) cases are expected to result from a genetic predisposition, but in only 5-10% of these cases highly penetrant germline mutations are found. The ...remaining CRC heritability is still unexplained, and may be caused by a hitherto-undefined set of rare variants with a moderately penetrant risk. Here we aimed to identify novel risk factors for early-onset CRC using whole-exome sequencing, which was performed on a cohort of CRC individuals (n = 55) with a disease onset before 45 years of age. We searched for genes that were recurrently affected by rare variants (minor allele frequency ≤ 0.001) with potentially damaging effects and, subsequently, re-sequenced the candidate genes in a replication cohort of 174 early-onset or familial CRC individuals. Two functionally relevant genes with low frequency variants with potentially damaging effects, PTPN12 and LRP6, were found in at least three individuals. The protein tyrosine phosphatase PTP-PEST, encoded by PTPN12, is a regulator of cell motility and LRP6 is a component of the WNT-FZD-LRP5-LRP6 complex that triggers WNT signaling. All variants in LRP6 were identified in individuals with an extremely early-onset of the disease (≤30 years of age), and two of the three variants showed increased WNT signaling activity in vitro. In conclusion, we present PTPN12 and LRP6 as novel candidates contributing to the heterogeneous susceptibility to CRC.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Molecular sensing in the lingual mucosa and in the gastro-intestinal tract play a role in the detection of ingested harmful drugs and toxins. Therefore, genetic polymorphisms affecting the capability ...of initiating these responses may be critical for the subsequent efficiency of avoiding and/or eliminating possible threats to the organism. By using a tagging approach in the region of Taste Receptor 2R38 (TAS2R38) gene, we investigated all the common genetic variation of this gene region in relation to colorectal cancer risk with a case-control study in a German population (709 controls and 602 cases) and in a Czech population (623 controls and 601 cases). We found that there were no significant associations between individual SNPs of the TAS2R38 gene and colorectal cancer in the Czech or in the German population, nor in the joint analysis. However, when we analyzed the diplotypes and the phenotypes we found that the non-taster group had an increased risk of colorectal cancer in comparison to the taster group. This association was borderline significant in the Czech population, (OR = 1.28, 95% CI 0.99-1.67; P(value) = 0.058) and statistically significant in the German population (OR = 1.36, 95% CI 1.06-1.75; P(value) = 0.016) and in the joint analysis (OR = 1.34, 95% CI 1.12-1.61; P(value) = 0.001). In conclusion, we found a suggestive association between the human bitter tasting phenotype and the risk of CRC in two different populations of Caucasian origin.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Patients with Lynch syndrome are at high risk for developing colorectal cancer (CRC). Regular colonoscopic surveillance is recommended, but there is no international consensus on the appropriate ...interval. We investigated whether shorter intervals are associated with lower CRC incidence and detection at earlier stages by comparing the surveillance policies in Germany, which evaluates patients by colonoscopy annually, in the Netherlands (patients evaluated at 1–2-year intervals), and Finland (patients evaluated at 2–3-year intervals).
We collected data from 16,327 colonoscopic examinations (conducted from 1984 through 2015) of 2747 patients with Lynch syndrome (pathogenic variants in the MLH1, MSH2, or MSH6 genes) from the German HNPCC Consortium, the Dutch Lynch Syndrome Registry, and the Finnish Lynch Syndrome Registry. Our analysis included 23,309 person-years of cumulative observation time. Time from the index colonoscopy to incident CRC or adenoma was analyzed using the Kaplan-Meier method; groups were compared using the log-rank test. We performed multivariable Cox regression analyses to identify factors associated with CRC risk (diagnosis of CRC before the index colonoscopy, sex, mutation, age, and presence of adenoma at the index colonoscopy).
The 10-year cumulative CRC incidence ranged from 4.1% to 18.4% in patients with low- and high-risk profiles, respectively, and varied with age, sex, mutation, and prior detection of CRC or adenoma. Observed colonoscopy intervals were largely in accordance with the country-specific recommendations. We found no significant differences in cumulative CRC incidence or CRC stage at detection among countries. There was no significant association between CRC stage and time since last colonoscopy.
We did not find a significant reduction in CRC incidence or stage of detection in Germany (annual colonoscopic surveillance) than in countries with longer surveillance intervals (the Netherlands, with 1–2-year intervals, and Finland, with 2–3-year intervals). Overall, we did not find a significant association of the interval with CRC risk, although age, sex, mutation, and prior neoplasia were used to individually modify colonoscopy intervals. Studies are needed to develop and validate risk-adapted surveillance strategies and to identify patients who benefit from shorter surveillance intervals.
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In our study, we evaluated the effectiveness of upper gastrointestinal (GI) endoscopy as an instrument for early gastric cancer (GC) detection in Lynch syndrome (LS) patients by analyzing data from ...the registry of the German Consortium for Familial Intestinal Cancer. In a prospective, multicenter cohort study, 1128 out of 2009 registered individuals with confirmed LS underwent 5176 upper GI endoscopies. Compliance was good since 77.6% of upper GI endoscopies were completed within the recommended interval of 1 to 3 years. Forty‐nine GC events were observed in 47 patients. MLH1 (n = 21) and MSH2 (n = 24) mutations were the most prevalent. GCs in patients undergoing regular surveillance were diagnosed significantly more often in an early‐stage disease (UICC I) than GCs detected through symptoms (83% vs 25%; P = .0231). Thirty‐two (68%) patients had a negative family history of GC. The median age at diagnosis was 51 years (range 28‐66). Of all GC patients, 13 were diagnosed at an age younger than 45. Our study supports the recommendation of regular upper GI endoscopy surveillance for LS patients beginning no later than at the age of 30.
What's new?
Risk of gastric cancer (GC) is significantly increased among patients with Lynch syndrome (LS). GC screening in LS patients, however, is fraught with uncertainty, particularly regarding the use of esophagogastroduodenoscopy (EGD). The authors of this study investigated the use of EGD for regular GC surveillance in a German cohort of LS patients. Regular surveillance by EGD resulted in more frequent diagnosis and significant down‐staging of GC, relative to detection via symptoms alone. In most cases, family history of GC was negative. This study supports recommendations for regular gastroscopic surveillance in LS patients starting by age 30.
Bloom syndrome is an autosomal recessive disorder characterized by chromosomal instability and increased cancer risk, caused by biallelic mutations in the RECQL-helicase gene BLM. Previous studies ...have led to conflicting conclusions as to whether carriers of heterozygous BLM mutations have an increased risk to develop colorectal cancer (CRC). We recently identified two carriers of a pathogenic BLM mutation in a cohort of 55 early-onset CRC patients (≤45 years of age), suggesting an overrepresentation compared to the normal population. Here, we performed targeted sequencing using molecular inversion probes to screen an additional cohort of 185 CRC patients (≤50 years of age) and 532 population-matched controls for deleterious BLM mutations. In total, we identified three additional CRC patients (1.6%) and one control individual (0.2%) that carried a known pathogenic BLM mutation, suggesting that these mutations are enriched in early-onset CRC patients (P = 0.05516). A comparison with local and publically available databases from individuals without suspicion for hereditary cancer confirmed this enrichment (P = 0.003534). Analysis of family members of the five BLM mutation carriers with CRC suggests an incomplete penetrance for CRC development. Therefore, these data indicate that carriers of deleterious BLM mutations are at increased risk to develop CRC, albeit with a moderate-to-low penetrance.
Pathogenic variants affecting MLH1, MSH2, MSH6, and PMS2 cause Lynch syndrome and result in different but imprecisely known cancer risks. This study aimed to provide age and organ-specific cancer ...risks according to gene and gender and to determine survival after cancer.
We conducted an international, multicenter prospective observational study using independent test and validation cohorts of carriers of class 4 or class 5 variants. After validation the cohorts were merged providing 6350 participants and 51,646 follow-up years.
There were 1808 prospectively observed cancers. Pathogenic MLH1 and MSH2 variants caused high penetrance dominant cancer syndromes sharing similar colorectal, endometrial, and ovarian cancer risks, but older MSH2 carriers had higher risk of cancers of the upper urinary tract, upper gastrointestinal tract, brain, and particularly prostate. Pathogenic MSH6 variants caused a sex-limited trait with high endometrial cancer risk but only modestly increased colorectal cancer risk in both genders. We did not demonstrate a significantly increased cancer risk in carriers of pathogenic PMS2 variants. Ten-year crude survival was over 80% following colon, endometrial, or ovarian cancer.
Management guidelines for Lynch syndrome may require revision in light of these different gene and gender-specific risks and the good prognosis for the most commonly associated cancers.
Summary Background Lynch syndrome is caused by germline mutations in MSH2, MLH1, MSH6 , and PMS2 mismatch-repair genes and leads to a high risk of colorectal and endometrial cancer. We previously ...showed that constitutional 3′ end deletions of EPCAM can cause Lynch syndrome through epigenetic silencing of MSH2 in EPCAM -expressing tissues, resulting in tissue-specific MSH2 deficiency. We aim to establish the risk of cancer associated with such EPCAM deletions. Methods We obtained clinical data for 194 carriers of a 3′ end EPCAM deletion from 41 families known to us at the Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands and compared cancer risk with data from a previously described cohort of 473 carriers from 91 families with mutations in MLH1, MSH2, MSH6 , or a combined EPCAM–MSH2 deletion. Findings 93 of the 194 EPCAM deletion carriers were diagnosed with colorectal cancer; three of the 92 women with EPCAM deletions were diagnosed with endometrial cancer. Carriers of an EPCAM deletion had a 75% (95% CI 65–85) cumulative risk of colorectal cancer before the age of 70 years (mean age at diagnosis 43 years SD 12), which did not differ significantly from that of carriers of combined EPCAM–MSH2 deletion (69% 95% CI 47–91, p=0·8609) or mutations in MSH2 (77% 64–90, p=0·5892) or MLH1 (79% 68–90, p=0·5492), but was higher than noted for carriers of MSH6 mutation (50% 38–62, p<0·0001). By contrast, women with EPCAM deletions had a 12% 0–27 cumulative risk of endometrial cancer, which was lower than was that noted for carriers of a combined EPCAM–MSH2 deletion (55% 20–90, p<0·0001) or of a mutation in MSH2 (51% 33–69, p=0·0006) or MSH6 (34% 20–48, p=0·0309), but did not differ significantly from that noted for MLH1 (33% 15–51, p=0·1193) mutation carriers. This risk seems to be restricted to deletions that extend close to the MSH2 gene promoter. Of 194 carriers of an EPCAM deletion, three had duodenal cancer and four had pancreatic cancer. Interpretation EPCAM deletion carriers have a high risk of colorectal cancer; only those with deletions extending close to the MSH2 promoter have an increased risk of endometrial cancer. These results underscore the effect of mosaic MSH2 deficiency, leading to variable cancer risks, and could form the basis of an optimised protocol for the recognition and targeted prevention of cancer in EPCAM deletion carriers. Funding Sacha Swarttouw-Hijmans Foundation, Dutch Cancer Society, Deutsche Krebshilfe (German Cancer Aid), Hong Kong Cancer Fund, Hungarian Research Grant OTKA, Norwegian EEA Financial Mechanism (Hungarian National Institute of Oncology), and US National Cancer Institute.
Biallelic germline mutations affecting NTHL1 predispose carriers to adenomatous polyposis and colorectal cancer, but the complete phenotype is unknown. We describe 29 individuals carrying biallelic ...germline NTHL1 mutations from 17 families, of which 26 developed one (n = 10) or multiple (n = 16) malignancies in 14 different tissues. An unexpected high breast cancer incidence was observed in female carriers (60%). Mutational signature analysis of 14 tumors from 7 organs revealed that NTHL1 deficiency underlies the main mutational process in all but one of the tumors (93%). These results reveal NTHL1 as a multi-tumor predisposition gene with a high lifetime risk for extracolonic cancers and a typical mutational signature observed across tumor types, which can assist in the recognition of this syndrome.
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•Biallelic germline NTHL1 mutations predispose to a multi-tumor syndrome•Biallelic germline NTHL1 mutation carriers are at risk for breast cancer•Tumors from NTHL1-deficient patients reveal a cross-cancer NTHL1-associated signature•Mutational signature analyses can assist to identify germline DNA repair defects
In addition to the know colorectal tumors, Grolleman et al. find tumors in 13 tissue types, including a high breast cancer incidence, among 29 carriers of biallelic germline NTHL1 mutations and identify a mutation signature across tumor types, which may facilitate the identification and management of new cases.
Background & Aims Individuals with hereditary nonpolyposis colorectal cancer (HNPCC; Lynch syndrome) have a high risk for developing colorectal cancer (CRC). We evaluated the efficacy of annual ...surveillance colonoscopies to detect adenomas and CRCs. Methods In a prospective, multicenter cohort study, 1126 individuals underwent 3474 colonoscopies. We considered individuals from 3 groups of HNPCC families: those with a pathogenic germline mutation in a mismatch repair gene (MUT group), those without a mutation but with microsatellite instability (MSI group), and those who fufilled the Amsterdam criteria without microsatellite instability (MSS group). Results Compliance to annual intervals was good, with 81% of colonoscopies completed within 15 months. Ninety-nine CRC events were observed in 90 patients. Seventeen CRCs (17%) were detected through symptoms (8 before baseline colonoscopy, 8 at intervals >15 months to the preceding colonoscopy, and 1 interval cancer). Only 2 of 43 CRCs detected by follow-up colonoscopy were regionally advanced. Tumor stages were significantly lower among CRCs detected by follow-up colonoscopies compared with CRCs detected by symptoms ( P = .01). Cumulative CRC risk at the age of 60 years was similar in the MUT and MSI groups (23.0% combined; 95% confidence interval CI, 14.8%–31.2%) but considerably lower in the MSS group (1.8%; 95% CI, 0.0%–5.1%). Adenomas at baseline colonoscopy predicted an earlier occurrence of subsequent adenoma (hazard ratio, 2.6; 95% CI, 1.7–4.0) and CRC (hazard ratio, 3.9; 95% CI, 1.7–8.5), providing information about interindividual heterogeneity of adenomas and kinetics of CRC formation. Conclusions Annual colonoscopic surveillance is recommended for individuals with HNPCC. Less intense surveillance might be appropriate for MSS families.
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