Three-step site-directed mutagenesis screen identifies pathogenic MLH1 variants associated with Lynch syndrome.

BACKGROUND: Inactivating mutations in the MLH1 DNA mismatch repair (MMR) gene underlie 42% of Lynch syndrome (LS) cases. LS is a cancer predisposition causing early onset colorectal and endometrial cancer. Nonsense and frameshift alterations unambiguously cause LS. The phenotype of missense mutations that only alter a single amino acid is often unclear. These variants of uncertain significance (VUS) hinder LS diagnosis and family screening and therefore functional tests are urgently needed. We developed a functional test for MLH1 VUS termed 'oligonucleotide-directed mutation screening' (ODMS). METHODS: The MLH1 variant was introduced by oligonucleotide-directed gene modification in mouse embryonic stem cells that were subsequently exposed to the guanine analogue 6-thioguanine to determine whether the variant abrogated MMR. RESUTS: In a proof-of-principle analysis, we demonstrate that ODMS can distinguish pathogenic and non-pathogenic MLH1 variants with a sensitivity of >95% and a specificity of >91%. We subsequently applied the screen to 51 MLH1 VUS and identified 31 pathogenic variants. CONCLUSION: ODMS is a reliable tool to identify pathogenic MLH1 variants. Implementation in clinical diagnostics will improve clinical care of patients with suspected LS and their relatives.

Oligonucleotide-directed mutagenesis screen to identify pathogenic Lynch syndrome-associated MSH2 DNA mismatch repair gene variants.

Single-stranded DNA oligonucleotides can achieve targeted base-pair substitution with modest efficiency but high precision. We show that "oligo targeting" can be used effectively to study missense mutations in DNA mismatch repair (MMR) genes. Inherited inactivating mutations in DNA MMR genes are causative for the cancer predisposition Lynch syndrome (LS). Although overtly deleterious mutations in MMR genes can clearly be ascribed as the cause of LS, the functional implications of missense mutations are often unclear. We developed a genetic screen to determine the pathogenicity of these variants of uncertain significance (VUS), focusing on mutator S homolog 2 (MSH2). VUS were introduced into the endogenous Msh2 gene of mouse embryonic stem cells by oligo targeting. Subsequent selection for MMR-deficient cells using the guanine analog 6-thioguanine allowed the detection of MMR-abrogating VUS. The screen was able to distinguish weak and strong pathogenic variants from polymorphisms and was used to investigate 59 Msh2 VUS. Nineteen of the 59 VUS were identified as pathogenic. Functional assays revealed that 14 of the 19 detected variants fully abrogated MMR activity and that five of the detected variants attenuated MMR activity. Implementation of the screen in clinical practice allows proper counseling of mutation carriers and treatment of their tumors.

Genetic modifiers of CHEK2*1100delC-associated breast cancer risk.

PURPOSE: CHEK2*1100delC is a founder variant in European populations that confers a two- to threefold increased risk of breast cancer (BC). Epidemiologic and family studies have suggested that the risk associated with CHEK2*1100delC is modified by other genetic factors in a multiplicative fashion. We have investigated this empirically using data from the Breast Cancer Association Consortium (BCAC). METHODS: Using genotype data from 39,139 (624 1100delC carriers) BC patients and 40,063 (224) healthy controls from 32 BCAC studies, we analyzed the combined risk effects of CHEK2*1100delC and 77 common variants in terms of a polygenic risk score (PRS) and pairwise interaction. RESULTS: The PRS conferred odds ratios (OR) of 1.59 (95% CI: 1.21-2.09) per standard deviation for BC for CHEK2*1100delC carriers and 1.58 (1.55-1.62) for noncarriers. No evidence of deviation from the multiplicative model was found. The OR for the highest quintile of the PRS was 2.03 (0.86-4.78) for CHEK2*1100delC carriers, placing them in the high risk category according to UK NICE guidelines. The OR for the lowest quintile was 0.52 (0.16-1.74), indicating a lifetime risk close to the population average. CONCLUSION: Our results confirm the multiplicative nature of risk effects conferred by CHEK2*1100delC and the common susceptibility variants. Furthermore, the PRS could identify carriers at a high lifetime risk for clinical actions.Genet Med advance online publication 06 October 2016.

Rapid genetic counseling and testing in newly diagnosed breast cancer: Patients' and health professionals' attitudes, experiences, and evaluation of effects on treatment decision making.

BACKGROUND: Rapid genetic counseling and testing (RGCT) in newly diagnosed high-risk breast cancer (BC) patients may influence surgical treatment decisions. To successfully integrate RGCT in practice, knowledge of professionals', and patients' attitudes toward RGCT is essential. METHODS: Between 2008 and 2010, we performed a randomized clinical trial evaluating the impact of RGCT. Attitudes toward and experience with RGCT were assessed in 265 patients (at diagnosis, 6- and 12-month follow-up) and 29 medical professionals (before and after the recruitment period). RESULTS: At 6-month follow-up, more patients who had been offered RGCT felt they had been actively involved in treatment decision-making than patients who had been offered usual care (67% vs 48%, P = 0.06). Patients who received DNA-test results before primary surgery reported more often that RGCT influenced treatment decisions than those who received results afterwards (P < 0.01). Eighty-seven percent felt that genetic counseling and testing (GCT) should preferably take place between diagnosis and surgery. Most professionals (72%) agreed that RGCT should be routinely offered to eligible patients. Most patients (74%) and professionals (85%) considered surgeons the most appropriate source for referral. CONCLUSIONS: RGCT is viewed as helpful for newly diagnosed high-risk BC patients in choosing their primary surgery and should be offered routinely by surgeons.

PALB2, CHEK2 and ATM rare variants and cancer risk: data from COGS.

BACKGROUND: The rarity of mutations in PALB2, CHEK2 and ATM make it difficult to estimate precisely associated cancer risks. Population-based family studies have provided evidence that at least some of these mutations are associated with breast cancer risk as high as those associated with rare BRCA2 mutations. We aimed to estimate the relative risks associated with specific rare variants in PALB2, CHEK2 and ATM via a multicentre case-control study. METHODS: We genotyped 10 rare mutations using the custom iCOGS array: PALB2 c.1592delT, c.2816T>G and c.3113G>A, CHEK2 c.349A>G, c.538C>T, c.715G>A, c.1036C>T, c.1312G>T, and c.1343T>G and ATM c.7271T>G. We assessed associations with breast cancer risk (42 671 cases and 42 164 controls), as well as prostate (22 301 cases and 22 320 controls) and ovarian (14 542 cases and 23 491 controls) cancer risk, for each variant. RESULTS: For European women, strong evidence of association with breast cancer risk was observed for PALB2 c.1592delT OR 3.44 (95% CI 1.39 to 8.52, p=7.1×10-5), PALB2 c.3113G>A OR 4.21 (95% CI 1.84 to 9.60, p=6.9×10-8) and ATM c.7271T>G OR 11.0 (95% CI 1.42 to 85.7, p=0.0012). We also found evidence of association with breast cancer risk for three variants in CHEK2, c.349A>G OR 2.26 (95% CI 1.29 to 3.95), c.1036C>T OR 5.06 (95% CI 1.09 to 23.5) and c.538C>T OR 1.33 (95% CI 1.05 to 1.67) (p≤0.017). Evidence for prostate cancer risk was observed for CHEK2 c.1343T>G OR 3.03 (95% CI 1.53 to 6.03, p=0.0006) for African men and CHEK2 c.1312G>T OR 2.21 (95% CI 1.06 to 4.63, p=0.030) for European men. No evidence of association with ovarian cancer was found for any of these variants. CONCLUSIONS: This report adds to accumulating evidence that at least some variants in these genes are associated with an increased risk of breast cancer that is clinically important.

Comprehensive Mutation Analysis of PMS2 in a Large Cohort of Probands Suspected of Lynch Syndrome or Constitutional Mismatch Repair Deficiency Syndrome.

Monoallelic PMS2 germline mutations cause 5%-15% of Lynch syndrome, a midlife cancer predisposition, whereas biallelic PMS2 mutations cause approximately 60% of constitutional mismatch repair deficiency (CMMRD), a rare childhood cancer syndrome. Recently improved DNA- and RNA-based strategies are applied to overcome problematic PMS2 mutation analysis due to the presence of pseudogenes and frequent gene conversion events. Here, we determined PMS2 mutation detection yield and mutation spectrum in a nationwide cohort of 396 probands. Furthermore, we studied concordance between tumor IHC/MSI (immunohistochemistry/microsatellite instability) profile and mutation carrier state. Overall, we found 52 different pathogenic PMS2 variants explaining 121 Lynch syndrome and nine CMMRD patients. In vitro mismatch repair assays suggested pathogenicity for three missense variants. Ninety-one PMS2 mutation carriers (70%) showed isolated loss of PMS2 in their tumors, for 31 (24%) no or inconclusive IHC was available, and eight carriers (6%) showed discordant IHC (presence of PMS2 or loss of both MLH1 and PMS2). Ten cases with isolated PMS2 loss (10%; 10/97) harbored MLH1 mutations. We confirmed that recently improved mutation analysis provides a high yield of PMS2 mutations in patients with isolated loss of PMS2 expression. Application of universal tumor prescreening methods will however miss some PMS2 germline mutation carriers.

Functional variants at the 11q13 risk locus for breast cancer regulate cyclin D1 expression through long-range enhancers.

Analysis of 4,405 variants in 89,050 European subjects from 41 case-control studies identified three independent association signals for estrogen-receptor-positive tumors at 11q13. The strongest signal maps to a transcriptional enhancer element in which the G allele of the best candidate causative variant rs554219 increases risk of breast cancer, reduces both binding of ELK4 transcription factor and luciferase activity in reporter assays, and may be associated with low cyclin D1 protein levels in tumors. Another candidate variant, rs78540526, lies in the same enhancer element. Risk association signal 2, rs75915166, creates a GATA3 binding site within a silencer element. Chromatin conformation studies demonstrate that these enhancer and silencer elements interact with each other and with their likely target gene, CCND1.

Does rapid genetic counseling and testing in newly diagnosed breast cancer patients cause additional psychosocial distress? results from a randomized clinical trial.

PURPOSE: Female breast cancer patients carrying a BRCA1/2 mutation have an increased risk of second primary breast cancer. Rapid genetic counseling and testing (RGCT) before surgery may influence choice of primary surgical treatment. In this article, we report on the psychosocial impact of RGCT. METHODS: Newly diagnosed breast cancer patients at risk for carrying a BRCA1/2 mutation were randomized to an intervention group (offer of RGCT) or a usual care control group (ratio 2:1). Psychosocial impact and quality of life were assessed with the Impact of Events Scale, Hospital Anxiety and Depression Scale, Cancer Worry Scale, and the EORTC QLQ-C30 and QLQ-BR23. Assessments took place at study entry and at 6- and 12-month follow-up visits. RESULTS: Between 2008 and 2010, 265 patients were recruited into the study. Completeness of follow-up data was more than 90%. Of the 178 women in the intervention group, 177 had genetic counseling, of whom 71 (40%) had rapid DNA testing and 59 (33%) received test results before surgery. Intention-to-treat and per-protocol analyses showed no statistically significant differences between groups over time in any of the psychosocial outcomes. CONCLUSIONS: In this study, RGCT in newly diagnosed breast cancer patients did not have any measurable adverse psychosocial effects.

Functional analysis of MSH2 unclassified variants found in suspected Lynch syndrome patients reveals pathogenicity due to attenuated mismatch repair.

BACKGROUND: Lynch syndrome, an autosomal-dominant disorder characterised by high colorectal and endometrial cancer risks, is caused by inherited mutations in DNA mismatch repair (MMR) genes. Mutations fully abrogating gene function are unambiguously disease causing. However, missense mutations often have unknown functional implications, hampering genetic counselling. We have applied a novel approach to study three MSH2 unclassified variants (UVs) found in Dutch families with suspected Lynch syndrome. METHODS: The three mutations were recreated in the endogenous Msh2 gene in mouse embryonic stem cells by oligonucleotide-directed gene modification. The effect of the UVs on MMR activity was then tested using a set of functional assays interrogating the main MMR functions. RESULTS: We recreated and functionally tested three MSH2 UVs: MSH2-Y165D (c.493T>G), MSH2-Q690E (c.2068C>G) and MSH2-M813V (c.2437A>G). We observed reduced levels of MSH2-Y165D and MSH2-Q690E but not MSH2-M813V proteins. MSH2-M813V was able to support all MMR functions similar to wild-type MSH2, whereas MSH2-Y165D and MSH2-Q690E showed partial defects. CONCLUSIONS: Based on the results from our functional assays, we conclude that the MSH2-M813V variant is not disease causing. The MSH2-Y165D and MSH2-Q690E variants affect MMR function and are therefore likely the underlying cause of familial cancer predisposition. Since the MMR defect is partial, these variants may represent low penetrance alleles.

Breast and ovarian cancer risks in a large series of clinically ascertained families with a high proportion of BRCA1 and BRCA2 Dutch founder mutations.

BACKGROUND: BRCA1 or BRCA2 mutations confer increased risks of breast and ovarian cancer, but risks have been found to vary across studies and populations. METHODS: We ascertained pedigree data of 582 BRCA1 and 176 BRCA2 families and studied the variation in breast and ovarian cancer risks using a modified segregation analysis model. RESULTS: The average cumulative breast cancer risk by age 70 years was estimated to be 45% (95% CI 36 to 52%) for BRCA1 and 27% (95% CI 14 to 38%) for BRCA2 mutation carriers. The corresponding cumulative risks for ovarian cancer were 31% (95% CI 17 to 43%) for BRCA1 and 6% (95% CI 2 to 11%) for BRCA2 mutation carriers. In BRCA1 families, breast cancer relative risk (RR) increased with more recent birth cohort (p heterogeneity = 0.0006) and stronger family histories of breast cancer (p heterogeneity < 0.001). For BRCA1, our data suggest a significant association between the location of the mutation and the ratio of breast to ovarian cancer (p<0.001). By contrast, in BRCA2 families, no evidence was found for risk heterogeneity by birth cohort, family history or mutation location. CONCLUSIONS: BRCA1 mutation carriers conferred lower overall breast and ovarian cancer risks than reported so far, while the estimates of BRCA2 mutations were among the lowest. The low estimates for BRCA1 might be due to older birth cohorts, a moderate family history, or founder mutations located within specific regions of the gene. These results are important for a more accurate counselling of BRCA1/2 mutation carriers.

Common variants at 12p11, 12q24, 9p21, 9q31.2 and in ZNF365 are associated with breast cancer risk for BRCA1 and/or BRCA2 mutation carriers.

INTRODUCTION: Several common alleles have been shown to be associated with breast and/or ovarian cancer risk for BRCA1 and BRCA2 mutation carriers. Recent genome-wide association studies of breast cancer have identified eight additional breast cancer susceptibility loci: rs1011970 (9p21, CDKN2A/B), rs10995190 (ZNF365), rs704010 (ZMIZ1), rs2380205 (10p15), rs614367 (11q13), rs1292011 (12q24), rs10771399 (12p11 near PTHLH) and rs865686 (9q31.2). METHODS: To evaluate whether these single nucleotide polymorphisms (SNPs) are associated with breast cancer risk for BRCA1 and BRCA2 carriers, we genotyped these SNPs in 12,599 BRCA1 and 7,132 BRCA2 mutation carriers and analysed the associations with breast cancer risk within a retrospective likelihood framework. RESULTS: Only SNP rs10771399 near PTHLH was associated with breast cancer risk for BRCA1 mutation carriers (per-allele hazard ratio (HR) = 0.87, 95% CI: 0.81 to 0.94, P-trend = 3 × 10-4). The association was restricted to mutations proven or predicted to lead to absence of protein expression (HR = 0.82, 95% CI: 0.74 to 0.90, P-trend = 3.1 × 10-5, P-difference = 0.03). Four SNPs were associated with the risk of breast cancer for BRCA2 mutation carriers: rs10995190, P-trend = 0.015; rs1011970, P-trend = 0.048; rs865686, 2df-P = 0.007; rs1292011 2df-P = 0.03. rs10771399 (PTHLH) was predominantly associated with estrogen receptor (ER)-negative breast cancer for BRCA1 mutation carriers (HR = 0.81, 95% CI: 0.74 to 0.90, P-trend = 4 × 10-5) and there was marginal evidence of association with ER-negative breast cancer for BRCA2 mutation carriers (HR = 0.78, 95% CI: 0.62 to 1.00, P-trend = 0.049). CONCLUSIONS: The present findings, in combination with previously identified modifiers of risk, will ultimately lead to more accurate risk prediction and an improved understanding of the disease etiology in BRCA1 and BRCA2 mutation carriers.

Prediction of BRCA2-association in hereditary breast carcinomas using array-CGH.

Germline mutations in BRCA1/2 increase the lifetime risk for breast and ovarian cancer dramatically. Identification of such mutations is important for optimal treatment decisions and pre-symptomatic mutation screening in family members. Although current DNA diagnostics is able to identify many different mutations, it remains unclear, how many BRCA2-associated breast cancer cases remain unidentified as such. In addition, mutation scanning detects many unclassified variants (UV) for which the clinical relevance is uncertain. Therefore, our aim was to develop a test to identify BRCA2-association in breast tumors based on the genomic signature. A BRCA2-classifier was built using array-CGH profiles of 28 BRCA2-mutated and 28 sporadic breast tumors. The classifier was validated on an independent group of 19 BRCA2-mutated and 19 sporadic breast tumors. Subsequently, we tested 89 breast tumors from suspected hereditary breast (and ovarian) cancer (HBOC) families, in which either no BRCA1/2 mutation or an UV had been found by routine diagnostics. The classifier showed a sensitivity of 89% and specificity of 84% on the validation set of known BRCA2-mutation carriers and sporadic tumor cases. Of the 89 HBOC cases, 17 presented a BRCA2-like profile. In three of these cases additional indications for BRCA2-deficiency were found. Chromosomal aberrations that were specific for BRCA2-mutated tumors included loss on chromosome arm 13q and 14q, and gain on 17q. Since we could separate BRCA1-like, BRCA2-like, and sporadic-like tumors, using our current BRCA2- and previous BRCA1-classifier, this method of breast tumor classification could be applied as additional test for current diagnostics to help clinicians in decision making and classifying sequence variants of unknown significance.

Compliance with periodic surveillance for Von-Hippel-Lindau disease.

PURPOSE: To assess compliance with a periodic surveillance regimen for Von Hippel-Lindau disease. METHODS: In this nationwide study, Von Hippel-Lindau disease mutation carriers and those at 50% risk were invited to complete a questionnaire assessing (compliance with) advice given for periodic surveillance. Medical record data on compliance with recommended radiologic surveillance examinations were also collected. RESULTS: Of the 84 (77%) participants, 78 indicated having received advice to undergo periodic surveillance. Of these, 71 reported being fully compliant with that advice. In 64% of the cases, this advice was only partially consistent with published guidelines. Based on medical record data, between one quarter and one third of individuals did not undergo surveillance as recommended in the guidelines for central nervous system lesions and one half for visceral lesions. Screening delay for central nervous system lesions was significantly higher in one hospital and in those cases where "the advice given" deviated from the guidelines. CONCLUSIONS: The majority of those with or at risk of Von Hippel-Lindau disease reported having received and being fully compliant with screening advice. However, in many cases, the advice given was only partially consistent with published guidelines, and screening delays were observed. Efforts should be undertaken to stimulate guideline-based surveillance advice and to minimize screening delay.

Behavioral and psychosocial effects of rapid genetic counseling and testing in newly diagnosed breast cancer patients: design of a multicenter randomized clinical trial.

BACKGROUND: It has been estimated that between 5% and 10% of women diagnosed with breast cancer have a hereditary form of the disease, primarily caused by a BRCA1 or BRCA2 gene mutation. Such women have an increased risk of developing a new primary breast and/or ovarian tumor, and may therefore opt for preventive surgery (e.g., bilateral mastectomy, oophorectomy). It is common practice to offer high-risk patients genetic counseling and DNA testing after their primary treatment, with genetic test results being available within 4-6 months. However, some non-commercial laboratories can currently generate test results within 3 to 6 weeks, and thus make it possible to provide rapid genetic counseling and testing (RGCT) prior to primary treatment. The aim of this study is to determine the effect of RGCT on treatment decisions and on psychosocial health. METHODS/DESIGN: In this randomized controlled trial, 255 newly diagnosed breast cancer patients with at least a 10% risk of carrying a BRCA gene mutation are being recruited from 12 hospitals in the Netherlands. Participants are randomized in a 2:1 ratio to either a RGCT intervention group (the offer of RGCT directly following diagnosis with tests results available before surgical treatment) or to a usual care control group. The primary behavioral outcome is the uptake of direct bilateral mastectomy or delayed prophylactic contralateral mastectomy. Psychosocial outcomes include cancer risk perception, cancer-related worry and distress, health-related quality of life, decisional satisfaction and the perceived need for and use of additional decisional counseling and psychosocial support. Data are collected via medical chart audits and self-report questionnaires administered prior to randomization, and at 6 month and at 12 month follow-up. DISCUSSION: This trial will provide essential information on the impact of RGCT on the choice of primary surgical treatment among women with breast cancer with an increased risk of hereditary cancer. This study will also provide data on the psychosocial consequences of RGCT and of risk-reducing behavior. TRIAL REGISTRATION: The study is registered at the Netherlands Trial Register (NTR1493) and ClinicalTrials.gov (NCT00783822).

TP53 germline mutation testing in 180 families suspected of Li-Fraumeni syndrome: mutation detection rate and relative frequency of cancers in different familial phenotypes.

BACKGROUND Li-Fraumeni syndrome (LFS) is a rare autosomal dominant cancer predisposition syndrome. Most families fulfilling the classical diagnostic criteria harbour TP53 germline mutations. However, TP53 germline mutations may also occur in less obvious phenotypes. As a result, different criteria are in use to decide which patients qualify for TP53 mutation analysis, including the LFS, Li-Fraumeni-like (LFL) and Chompret criteria. We investigated which criteria for TP53 mutation analysis resulted in the highest mutation detection rate and sensitivity in Dutch families. We describe the tumour spectrum in TP53-positive families and calculated tumour type specific relative risks. METHOD A total of 180 Dutch families referred for TP53 mutation analysis were evaluated. Tumour phenotypes were verified by pathology reports or clinical records. RESULTS A TP53 germline mutation was identified in 24 families. When the Chompret criteria were used 22/24 mutations were detected (sensitivity 92%, mutation detection rate 21%). In LFS and LFL families 18/24 mutations were found (sensitivity 75%). The two mutations detected outside the 'Chompret group' were found in a child with rhabdomyosarcoma and a young woman with breast cancer. In the mutation carriers, in addition to the classical LFS tumour types, colon and pancreatic cancer were also found significantly more often than in the general population. CONCLUSION We suggest TP53 mutation testing for all families fulfilling the Chompret criteria. In addition, TP53 mutation testing can be considered in the event of childhood sarcoma and breast cancer before 30 years. In addition to the risk for established LFS tumour types, TP53-positive individuals may also have an elevated risk for pancreatic and colon cancer.

A randomized experimental study to test the effects of discussing uncertainty during cancer genetic counseling: different strategies, different outcomes?

Uncertainty is increasingly discussed during genetic counseling due to innovative techniques, e.g., multigene panel testing. Discussions about uncertainty may impact counselees variably, depending on counselors' communication styles. Ideally, the discussion of uncertainty enables counselees to cope with uncertainty and make well-informed decisions about testing. We examined the impact of how counselors convey uncertainty and address counselees' uncertainty, and explored the role of individual characteristics. Therefore, a randomized controlled experiment using videos was conducted. Former counselees (N = 224) viewed one video depicting a genetic consultation about multigene panel testing. The extent of counselors' communication of uncertainty (comprehensive vs. the essence) and their response to counselees' uncertainty expressions (providing information vs. providing space for emotions vs. normalizing and counterbalancing uncertainty) were systematically manipulated. Individual characteristics, e.g., uncertainty tolerance, were assessed, as well as outcome variables (primary outcomes: feelings of uncertainty and information recall). No effects were found on primary outcomes. Participants were most satisfied when the essence was communicated, combined with providing information or providing space responses (p = 0.002). Comprehensive information resulted in less perceived steering toward testing (p = 0.005). Participants with lower uncertainty tolerance or higher trait anxiety were less confident about their understanding when receiving comprehensive information (p = 0.025). Participants seeking information experienced less uncertainty (p = 0.003), and trusted their counselor more (p = 0.028), when the counselor used information providing responses. In sum, the impact of discussing uncertainty primarily depends on individual characteristics. Practical guidelines should address how to tailor the discussion of uncertainty.

Prophylactic mastectomy in BRCA1 and BRCA2 mutation carriers: very low risk for subsequent breast cancer.

AIM: To examine the outcome of prophylactic mastectomy in a hospital-based series of BRCA1/2 gene mutation carriers with and without a history of breast cancer. PATIENTS AND METHODS: A center-based consecutive series of 254 BRCA1/2 gene mutation carriers that had prophylactic mastectomy after a normal surveillance round including breast-magnetic resonance imaging were identified. One hundred forty-seven asymptomatic carriers underwent bilateral mastectomy and 107 symptomatic women had contralateral mastectomy after a mean cancer free interval of 3.6 years. All removed breasts were histopathologically examined. RESULTS: In one asymptomatic BRCA2 carrier (0.7%) an occult small invasive breast cancer was diagnosed, while in 6 asymptomatic carriers (4.0% BRCA1 and 4.3% BRCA2) and in 5 symptomatic carriers (2.5% BRCA1 and 10.7% BRCA2) DCIS was detected at prophylactic mastectomy. No breast cancer occurred in the asymptomatic group after a postprophylactic follow-up period of 778 women-years. In the symptomatic carriers 1 invasive breast cancer was detected after 580 follow-up years. From age-, cohort-, and gene-specific reference data we calculated that 15 invasive first cancers in the asymptomatic carriers were prevented during follow-up. CONCLUSION: One invasive breast cancer in 147 bilateral prophylactic mastectomies (0.7%) was detected, this makes a sentinel node procedure redundant and preoperative imaging vital. The prophylactic procedure is highly effective in preventing invasive breast cancer in BRCA1/2 mutation carriers. Since the remaining risk is less than 0.2%/woman-year, continued surveillance of the asymptomatic carriers is not warranted.

Chromosome 8q23.3 and 11q23.1 variants modify colorectal cancer risk in Lynch syndrome.

BACKGROUND & AIMS: Recent genome-wide association studies have identified common low-risk variants for colorectal cancer (CRC). To assess whether these influence CRC risk in the Lynch syndrome, we genotyped these variants in a large series of proven mutation carriers. METHODS: We studied 675 individuals from 127 different families from the Dutch Lynch syndrome Registry whose mutation carrier status was known. We genotyped 8q24.21, 8q23.3, 10p14, 11q23.1, 15q13.3, and 18q21.1 variants in carriers of a mismatch repair gene mutation. Univariate and multivariate analysis was used to analyse the association between the presence of a risk variant and CRC risk. RESULTS: A significant association was found between CRC risk and rs16892766 (8q23.3) and rs3802842 (11q23.1). For rs16892766, possession of the C-allele was associated with an elevated risk of CRC in a dose-dependent fashion, with homozygosity for CC being associated with a 2.16-fold increased risk. For rs3802842, the increased risk of CRC associated with the C-allele was only found among female carriers, while CRC risk was substantially higher among homozygous (hazard ratio [HR] 3.08) than among heterozygous carriers of the C-allele (HR 1.49). In an additive model of both variants, the risk was significantly associated with the number of risk alleles (HR 1.60 for carriers of 2 or more risk alleles). The effects were stronger in female carriers than in male carriers. CONCLUSION: We have identified 2 loci that are significantly associated with CRC risk in Lynch syndrome families. These modifiers may be helpful in identifying high-risk individuals who require more intensive surveillance.

Physical activity and the risk of breast cancer in BRCA1/2 mutation carriers.

BRCA1/2 mutation carriers have a high lifetime risk of developing breast cancer. Differences in penetrance indicate that this risk may be influenced by lifestyle factors. Because physical activity is one of the few modifiable risk factors, it may provide a target to add to breast cancer prevention in this high-risk population. We examined the association between self-reported lifetime sports activity and breast cancer risk in a nationwide retrospective cohort study, including 725 carriers, of whom 218 had been diagnosed with breast cancer within 10 years prior to questionnaire completion. We found a nonsignificantly decreased risk for ever engaging in sports activity (HR = 0.84, 95%CI = 0.57-1.24). Among women who had participated in sports, a medium versus low level of intensity and duration (i.e., between 11.0 and 22.7 mean MET hours/week averaged over a lifetime) reduced the risk of breast cancer (HR = 0.59, 95%CI = 0.36-0.95); no dose-response trend was observed. For mean hours/week of sports activity, a nonsignificant trend was observed (HR(low versus never) = 0.93, 95%CI = 0.60-1.43; HR(medium versus never) = 0.81, 95%CI = 0.51-1.29; HR(high versus never) = 0.78, 95%CI = 0.48-1.29; p (trend overall) = 0.272; p (trend active women) = 0.487). For number of years of sports activity no significant associations were found. Among women active in sports before age 30, mean MET hours/week showed the strongest inverse association of all activity measures (HR(medium versus low) = 0.60, 95%CI = 0.38-0.96; HR(high versus low) = 0.58, 95%CI = 0.35-0.94; p (trend) = 0.053). Engaging in sports activity after age 30 was also inversely associated with breast cancer risk (HR = 0.63, 95%CI = 0.44-0.91). Our results indicate that sports activity may reduce the risk of breast cancer in BRCA1/2 mutation carriers.

Psychological distress and use of psychosocial support in familial adenomatous polyposis.

OBJECTIVE: Familial adenomatous polyposis (FAP) is characterized by multiple adenomas in the colorectum with a high risk to develop colorectal cancer. It is unclear whether individuals at risk of FAP experience distress due to this potentially life-threatening disease. This nationwide study assessed: (1) the prevalence of psychological distress; and (2) the need for and use of specialized professional psychosocial support. METHODS: In this cross-sectional study, all individuals from families at high risk for FAP registered at the Netherlands Foundation for the Detection of Hereditary Tumours were invited to complete a questionnaire assessing, among other issues, generalized, cancer-specific and FAP-specific distress. RESULTS: In total, 525 individuals completed the questionnaire. Approximately 20% of the respondents had moderate to severe levels of FAP-specific distress. Levels of generalized distress were comparable to the general Dutch population. Significantly more individuals with a FAP diagnosis had frequent cancer worries than those at risk of FAP or non-carriers (p=0.02). Distress levels were more strongly associated with psychosocial variables (e.g. perceived cancer risk), than with sociodemographic or clinical variables. Up to 43% of the variance in distress could be explained by all variables combined. Of those moderately to severely distressed, 26% had received specialized professional psychosocial support, while 30% of those did not receive the support they wanted. CONCLUSIONS: A substantial minority of individuals reported moderate to severe distress levels associated with FAP. However, only one-third of those received specialized professional psychosocial support. We recommend the use of a screening questionnaire to identify individuals in need of such support.