Sarcoma in neurofibromatosis 2: case report and review of the literature.

Neurofibromatosis type 2 (NF2) is associated with the development of several types of benign nervous system tumours, while malignancies are rare. We report a 22-year-old man who presented with retroperitoneal and spinal high-grade sarcomas with epithelial features. Samples showed a mixed epithelioid and spindled cell content with little associated matrix and inconclusive immunochemistry. Genetic analysis of a schwannoma and matched blood samples demonstrated a constitutional de novo substitution at the splice donor site of intron 8 of the NF2 gene and aa acquired large deletion of the entire NF2 gene as a second hit, with some loss of SMARCB1. The sarcoma also showed evidence of loss of SMARCB1 and NF2 with loss of INI1 staining. Unfortunately the mass was unresectable and the patient died 6 months after diagnosis. This malignancy was most consistent with SMARCB1-deficient epithelioid malignant peripheral nerve sheath tumour, although a significant differential was proximal-type epithelial sarcoma. Each differential has previously been reported only once with NF2. This demonstrates an extremely rare potential complication of the condition.

Neurofibromatosis type 2.

Type 2 neurofibromatosis (NF2) is an autosomal dominant disorder caused by mutations in the NF2 tumor suppressor gene NF2 on chromosome 22. Around 1 in 33000 people are born with an NF2 mutation although more than one-third of the 60% of de novo cases are not conceived with the mutation but this develops later in embryogenesis (mosaics). NF2 has a substantial effect on life expectancy and individuals with a constitutional truncating mutation have the worst prognosis. The vast majority of people with NF2 will develop bilateral vestibular schwannomas with many developing schwannomas on other cranial, spinal and peripheral nerves. Cranial and spinal meningiomas and intraspinal low grade indolent ependymomas are the other major tumor features. Cutaneous features can be subtle with only 70% having evidence of intracutaneous plaque-like schwannomas or subcutaneous lesions on peripheral nerves. Café-au-lait patches are more frequent than in the general population but in only around 1% will meet NIH criteria for NF1.

Reproductive decision-making in young female carriers of a BRCA mutation.

STUDY QUESTION: How do young women, who were identified as carrying a BRCA gene mutation before they had children, approach reproductive decision-making and what are their attitudes towards reproductive genetic testing? SUMMARY ANSWER: Reproductive decision-making within the context of cancer risk is complex and influenced by personal experiences of cancer. Younger women were not concerned with reproductive decision-making at the time of their genetic test; however, the impact on subsequent reproductive decision-making was considerable and left them with unanticipated dilemmas, such as having children who would be at risk of inheriting cancer predisposition, timing risk-reducing surgery and changing perceptions of responsibility. WHAT IS KNOWN ALREADY: Individuals carrying gene mutations predisposing to hereditary breast/ovarian cancer have concerns about passing on the gene mutation to children. STUDY DESIGN, SIZE, DURATION: Qualitative methodology and thematic analysis. PARTICIPANTS/MATERIALS, SETTING, METHODS: Data were collected through semi-structured interviews with 25 women aged 18-45 who had received a positive result for a BRCA1 or BRCA2 gene mutation while childless. MAIN RESULTS AND THE ROLE OF CHANCE: Analysis revealed four central themes: (i) the impact of cancer on reproductive decision-making; (ii) motivation for genetic testing; (iii) risk management and timing of planning children; and (iv) optimism for future medical advancements. LIMITATIONS, REASONS FOR CAUTION: This study explores the views of female BRCA carriers. Further research should explore the views of couples, men, and include samples with greater ethnic and social diversity. WIDER IMPLICATIONS OF THE FINDINGS: This evidence highlights the need for reproductive decision-making to be addressed at the time of pretest genetic counselling. More information should be provided on reproductive options as well as counselling/support to guide women's reproductive decision-making and prenatal testing options at the time they undertake genetic testing. STUDY FUNDING/COMPETING INTEREST(S): This research was supported by Cancer Research UK (Number C1226 A7920) and NIHR support to the Biomedical Research Centre at The Institute of Cancer Research and RMH. The authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: Not applicable.

Is multiple SNP testing in BRCA2 and BRCA1 female carriers ready for use in clinical practice? Results from a large Genetic Centre in the UK.

BRCA1 and BRCA2 are major breast cancer susceptibility genes. Nineteen single nucleotide polymorphisms (SNPs) at 18 loci have been associated with breast cancer. We aimed to determine whether these predict breast cancer incidence in women with BRCA1/BRCA2 mutations. BRCA1/2 mutation carriers identified through the Manchester genetics centre between 1996 and 2011 were included. Using published odds ratios (OR) and risk allele frequencies, we calculated an overall breast cancer risk SNP score (OBRS) for each woman. The relationship between OBRS and age at breast cancer onset was investigated using the Cox proportional hazards model, and predictive ability assessed using Harrell's C concordance statistic. In BRCA1 mutation carriers we found no association between OBRS and age at breast cancer onset: OR for the lowest risk quintile compared to the highest was 1.20 (95% CI 0.82-1.75, Harrell's C = 0.54), but in BRCA2 mutation carriers the association was significant (OR for the lowest risk quintile relative to the highest was 0.47 (95% CI 0.33-0.69, Harrell's C = 0.59). The 18 validated breast cancer SNPs differentiate breast cancer risks between women with BRCA2 mutations, but not BRCA1. It may now be appropriate to use these SNPs to help women with BRCA2 mutations make maximally informed decisions about management options.

Metachronous colorectal cancer risk in patients with a moderate family history.

AIM: Lifetime risk of a metachronous colorectal cancer (mCRC) is 0.6-3% following sporadic colorectal cancer (CRC) and 15-26% in Lynch syndrome. The lifetime incidence of CRC in individuals with moderate familial risk is 8-17%. Risk of mCRC is unknown. METHOD: A retrospective longitudinal study of the Regional Familial CRC Registry was performed. Patients who had at least one CRC were categorized as follows: moderate risk (n = 383), Lynch syndrome (n = 528) and average (population) risk (n = 409). The Kaplan-Meier estimate (1-KM) and the cumulative incidence function were used to calculate the risk of mCRC. The 1-KM gives the risk for individuals remaining at risk (alive) at a given time point and thus is useful for counselling. The cumulative incidence function gives the risk for the whole population. RESULTS: The 1-KM and the cumulative incidence function demonstrated that the risk of mCRC was significantly higher in moderate-risk patients compared with average (population)-risk patients (1-KM, P = 0.008; cumulative incidence function, P = 0.00097). However, the risk of mCRC was higher in patients with Lynch syndrome than in moderate-risk or average (population)-risk patients. The 1-KM in moderate-risk patients was 2.7%, 6.3% and 23.5% at 5, 10 and 20 years, respectively. In average (population)-risk patients, the 1-KM was 1.3%, 3.1% and 7.0% at 5, 10 and 20 years, and the cumulative incidence function was 0.3%, 0.6% and 2.4% at the same time points, respectively. CONCLUSION: These data indicate that the risk of mCRC is significantly higher in patients with a moderate family history of CRC than in those with an average (population) risk. This justifies proactive lifelong surveillance.

Genotype-phenotype correlation in colorectal polyposis.

Familial adenomatous polyposis (FAP) has been divided into three clinical subtypes: mild, classical and severe. This study aimed to investigate for a correlation between genotype and phenotype. A codon-specific survival difference is unknown. A retrospective longitudinal study of 492 patients on the Manchester Polyposis Registry was conducted. Patients were grouped according to genotypes: 0, unknown mutation; 1, adenomatous polyposis coli (APC) 0-178 (and 312-412 of exon 9); 2, APC >1550; 3, APC 179-1249; 4, APC 1250-1549; and 5, MutYH. Date of onset of polyposis, incidence of colorectal cancer (CRC), survival and actuarial time to surgery were calculated. Median age of onset of polyposis for genotype 0 was 20.3 years, genotype 1 35.6 years, genotype 2 32.2, genotype 3 15.9 years, and genotype 4 14.8 years (p < 0.0001). Age of onset of CRC was similar between genotypes. Median survival for genotype 0 was 56.6 years, genotype 1 74.9 years, genotype 2 61.0 years, genotype 3 63.0 years, genotype 4 48.1 years, and genotype 5 69.7 years (p = 0.003). This survival difference was also seen when patients who underwent screening and those who did not were analysed separately. Survival in the screened population was 53.9 years in genotype 4 and 72.9 years in genotype 3. Patients with genotype 4 (APC 1249-1549) have a significantly worse survival despite screening and early prophylactic surgery. This analysis supports a genotype-phenotype correlation. Patients with a mutation APC 1249-1549 develop polyposis at an early age and have a worse survival. Patients with a mutation APC 0-178 or 312-412 develop polyposis later and have an improved survival. This survival difference has not previously been documented.

Risk of cancer other than breast or ovarian in individuals with BRCA1 and BRCA2 mutations.

The risks of cancers other than breast and ovarian amongst BRCA1 and BRCA2 mutation carriers are based on relatively few family based studies with the risk of specific cancers tested in population based samples of cancers from founder populations. We assessed risks of "other cancers" in 268 BRCA1 families and 222 BRCA2 families using a person years at risk analysis from 1975 to 2005. Cancer confirmations were overall higher than in previous family based studies at 64%. There was no overall increase in risk for BRCA1 carriers although oesophagus had a significant increased RR of 2.9 (95% CI 1.1-6.0) and stomach at 2.4 (95% CI 1.2-4.3), these were based mainly on unconfirmed cases. For BRCA2 increased risks for cancers of the pancreas (RR 4.1, 95% CI 1.9-7.8) and prostate (RR 6.3, 95% CI 4.3-9.0) and uveal melanoma (RR 99.4, 95% CI 11.1-359.8) were confirmed. Possible new associations with oesophagus (RR 4.1, 95% CI 1.9-7.8) and stomach (RR 2.7, 95% CI 1.3-4.8) were detected but these findings should be treated with caution due to lower confirmation rates. In contrast to previous research a higher risk of prostate cancer was found in males with mutations in the BRCA2 OCCR region. The present study strengthens the known links between BRCA2 and pancreatic and prostate cancer, but throws further doubt onto any association with BRCA1. New associations with upper gastro-intestinal malignancy need to be treated with caution and confirmed by large prospective studies.

Uptake of risk-reducing salpingo-oophorectomy in women carrying a BRCA1 or BRCA2 mutation: evidence for lower uptake in women affected by breast cancer and older women.

BACKGROUND: Bilateral risk-reducing salpingo-oophorectomy (BRRSO) is the only effective way of reducing mortality from ovarian cancer. This study investigates uptake of BRRSO in 700 BRCA1/2 mutation carriers from Greater Manchester. METHODS: Dates of last follow-up and BRRSO were obtained, and the following variables were investigated: ovarian cancer risk/gene, age and breast cancer history. The date of the genetic mutation report was the initiation for Kaplan-Meier analysis. RESULTS: The uptake of BRRSO in BRCA1 mutation carriers was 54.5% (standard error 3.6%) at 5 years post testing compared with 45.5% (standard error 3.2%) in BRCA2 mutation carriers (P=0.045). The 40-59 years category showed the greatest uptake for BRRSO and uptake was significantly lower in the over 60 s (P<0.0001). Of the unaffected BRCA1 mutation carriers, 65% (standard error 5.1%) opted for surgery at 5 years post-testing compared with 41.1% (standard error 5.1%) in affected BRCA1 mutation carriers (P=0.045). CONCLUSION: The uptake of BRRSO is lower in women previously affected by breast cancer and in older women. As there is no efficient method for early detection of ovarian cancer, uptake should ideally be greater. Counselling should be offered to ensure BRCA1/2 mutation carriers make an informed decision about managing their ovarian cancer risk.

Prostate cancer in BRCA2 germline mutation carriers is associated with poorer prognosis.

BACKGROUND: The germline BRCA2 mutation is associated with increased prostate cancer (PrCa) risk. We have assessed survival in young PrCa cases with a germline mutation in BRCA2 and investigated loss of heterozygosity at BRCA2 in their tumours. METHODS: Two cohorts were compared: one was a group with young-onset PrCa, tested for germline BRCA2 mutations (6 of 263 cases had a germline BRAC2 mutation), and the second was a validation set consisting of a clinical set from Manchester of known BRCA2 mutuation carriers (15 cases) with PrCa. Survival data were compared with a control series of patients in a single clinic as determined by Kaplan-Meier estimates. Loss of heterozygosity was tested for in the DNA of tumour tissue of the young-onset group by typing four microsatellite markers that flanked the BRCA2 gene, followed by sequencing. RESULTS: Median survival of all PrCa cases with a germline BRCA2 mutation was shorter at 4.8 years than was survival in controls at 8.5 years (P=0.002). Loss of heterozygosity was found in the majority of tumours of BRCA2 mutation carriers. Multivariate analysis confirmed that the poorer survival of PrCa in BRCA2 mutation carriers is associated with the germline BRCA2 mutation per se. CONCLUSION: BRCA2 germline mutation is an independent prognostic factor for survival in PrCa. Such patients should not be managed with active surveillance as they have more aggressive disease.

The relationship between patients' perception of the effects of neurofibromatosis type 2 and the domains of the Short Form-36.

OBJECTIVES: To investigate the relationship between those issues concerning quality of life in patients with neurofibromatosis type 2 (NF2) as identified by the closed set NF2 questionnaire and the eight norm-based measures and the physical component summary (PCS) and mental component summary (MCS) scores of the Short Form-36 (SF-36) Questionnaire. DESIGN: Postal questionnaire study. SETTING: Questionnaires sent to subjects' home addresses. PARTICIPANTS: Eighty-seven adult subjects under the care of the Manchester Multidisciplinary NF2 Clinic were invited to participate. MAIN OUTCOME MEASURES: Sixty-two (71%) completed sets of closed set NF2 questionnaires and SF-36 questionnaires were returned. RESULTS: Subjects with NF2 scored less than the norm of 50 on both the physical component summary and mental component summary scores and the eight individual norm-based measures of the Short Form-36 questionnaire. Correlations (using Kendall's tau) were examined between patients' perceptions of their severity of difficulty with the following activities and the eight norm-based measures and the physical component summary and mental component summary scores of the Short Form-36 questionnaire: Communicating with spouse/significant other (N = 61). The correlation coefficients were significant at the 0.01 level for the mental component summary score, together with three of the norm-based scores [vitality (VT), social functioning and role emotional]. Social communication (N = 62). All 10 correlations were significant at the 0.01 or 0.001 level. Balance (N = 59). All 10 correlations were highly significant at the P < 0.001 level. Hearing difficulties (N = 61). All correlations were significant at either the 0.01 level or less apart from the mental component summary score and three of the norm-based scores (role physical, VT and mental health). Mood change (N = 61). All correlations were significant at the 0.01 level or less, apart from one norm-based score (role physical). CONCLUSIONS: The Short Form-36 questionnaire has allowed us to relate patients' perceptions of their difficulties, as identified by the closed set NF2 questionnaire, to the physical and mental domains measured by this validated and widely used scale, and has provided further insight into areas of functioning affected by NF2.

The impact of screening and genetic registration on mortality and colorectal cancer incidence in familial adenomatous polyposis.

BACKGROUND: Regular colonic surveillance of familial adenomatous polyposis (FAP) patients is necessary to ensure appropriate prophylactic surgery is performed before colorectal cancer (CRC) develops. Polyposis Registries have been established to coordinate screening programmes. The aim of this study was to assess the effect of screening and of the formation of the Registry on survival, incidence of CRC and age at onset of CRC, in FAP patients. METHODS: Patients on the Manchester Polyposis Registry were categorised according to their mode of presentation; screening or symptomatic, and survival time from birth was calculated for each patient (n=353). The effect of the formation of the Registry was assessed by comparing survival times from birth for patients diagnosed in the 20 years before the establishment of the Registry, to patients diagnosed in the 20 years since the formation of the Registry (n=273). RESULTS: This study demonstrated that survival was increased from 57.8 years to 70.4 years (p<0.001) by screening, and from 58.1 years to 69.6 years (p=0.007) following establishment of the Polyposis Registry. The incidence of CRC was reduced from 43.5% to 3.8% by screening, and from 28.7% to 14.0% following establishment of the Polyposis Registry. Although direct causation between improved survival and reduced CRC incidence, and establishment of the Registry cannot be proven, an association has been demonstrated. Colorectal cancer was found to develop, on average, 16 years later in the screening population. CONCLUSION: A regular systematic large bowel screening programme, managed by a Polyposis Registry, significantly improves the prognosis of FAP.

Risk of breast cancer in male BRCA2 carriers.

The risk of breast cancer for unaffected men who test positive for a BRCA2 mutation is based on very few retrospective studies. We have used both retrospective and prospective analysis in 321 families with pathogenic BRCA2 mutations. Three breast cancers occurred in male first-degree relatives after family ascertainment in 4140 years of follow-up suggesting a risk of breast cancer to 80 years of 8.9%. A second analysis excluding index cases identified 16 breast cancers in 905 first-degree male relatives on which Kaplan-Meier analysis was performed after assigning carrier status. This analysis confirmed that breast cancer risk in men was 7.1% (SE 5.2-8.6%) by age 70 years and 8.4% (SE 6.2-10.6%) by age 80 years.

Long-term outcomes of breast cancer in women aged 30 years or younger, based on family history, pathology and BRCA1/BRCA2/TP53 status.

BACKGROUND: There are relatively few articles addressing long-term follow-up in women with breast cancer at very young ages. METHODS: We have updated and extended our population-based analysis of breast cancer diagnosed at the age < or =30 years in North-west England to include an extra 15 patients with mutation testing in BRCA1, BRCA2 and TP53, with 115 of 288 consecutive cases being tested. Kaplan-Meier curves were generated to assess overall survival, contralateral breast cancer and other second primaries. RESULTS: Survival analysis of all 288 patients showed poor overall survival, although this improved from a 15-year survival of only 46% in those diagnosed between 1980 and 1989 to 58% in those diagnosed between 1990 and 1997 (P=0.05). Contralateral breast cancer rates were at a steady rate of 0.6 per 1000, although the rates in mutation carriers were approximately 2 per 1000. Altogether, 16 BRCA1, 9 BRCA2 and 6 TP53 mutations have now been found among the 115 cases on whom DNA analysis has been performed. BRCAPRO accurately predicted the number of carriers for BRCA1 and BRCA2 and was sensitive and specific at the 10 and 20% threshold, respectively. However, BRCAPRO did not seem to give any weight to DCIS, which accounted for two BRCA1 carriers and three TP53 carriers and overpredicted mutations at the high end of the spectrum, with only 6 of 11 (54%) with a >90% probability having identifiable BRCA1/2 mutations. INTERPRETATION: Rates of new primaries are predicted to some extent by mutation status. BRCAPRO is useful at determining those patients aged < or =30 years to be tested.

Use of a closed set questionnaire to measure primary and secondary effects of neurofibromatosis type 2.

OBJECTIVES: To identify the greatest difficulties reported by people affected by neurofibromatosis type 2, and to determine the relationship between the primary and secondary effects of the disease. DESIGN: Postal questionnaire study. SETTING: Questionnaire sent to subjects' home addresses. PARTICIPANTS: Eighty-seven adult patients under the care of the Manchester multidisciplinary neurofibromatosis type 2 team were invited to take part. MAIN OUTCOME MEASURE: The response rate was 62 out of 87 (71 per cent). RESULTS: Respondents' answers emphasised that their greatest problem was deafness, which resulted in communication difficulties with social contacts, close partners, family and friends. Correlation coefficients indicated a relationship between general mood changes and hearing difficulties, social communication problems, balance difficulties and mobility problems. Self-confidence was significantly related only to social communication problems. CONCLUSIONS: The use of a closed set neurofibromatosis type 2 questionnaire identified hearing problems and subsequent communication difficulties as the main problems faced by people with this condition.

Addition of pathology and biomarker information significantly improves the performance of the Manchester scoring system for BRCA1 and BRCA2 testing.

BACKGROUND: Selection for genetic testing of BRCA1/BRCA2 is an important area of healthcare. Although testing costs for mutational analysis are falling, costs in North America remain in excess of US$3000 (UK price can be 690 pounds). Guidelines in most countries use a 10-20% threshold of detecting a mutation in BRCA1/2 combined within a family before mutational analysis is considered. A number of computer-based models have been developed. However, use of these models can be time consuming and difficult. The Manchester scoring system was developed in 2003 to simplify the selection process without losing accuracy. METHODS: In order to increase accuracy of prediction, breast pathology of the index case was incorporated into the Manchester scoring system based on 2156 samples from unrelated non-Jewish patients fully tested for BRCA1/2, and the scores were adapted accordingly. Results/ DISCUSSION: Data from breast pathology allowed adjustment of BRCA1 and combined BRCA1/2 scores alone. There was a lack of pathological homogeneity for BRCA2, therefore specific pathological correlates could not be identified. Upward adjustments in BRCA1 mutation prediction scores were made for grade 3 ductal cancers, oestrogen receptor (ER) and triple-negative tumours. Downward adjustments in the score were made for grade 1 tumours, lobular cancer, ductal carcinoma in situ and ER/HER2 positivity. Application of the updated scoring system led to four and nine more mutations in BRCA1 being identified at the 10% and 20% threshold, respectively. Furthermore, 65 and 58 fewer cases met the 10% and 20% threshold, respectively, for testing. Moreover, the adjusted score significantly improved the trade-off between sensitivity and specificity for BRCA1/2 prediction.

Comparison of proactive and usual approaches to offering predictive testing for BRCA1/2 mutations in unaffected relatives.

There have been few studies addressing uptake of predictive testing for BRCA1/2, only one comparing a proactive with usual family networking approach to dissemination. We report uptake of predictive genetic testing after directly offering BRCA1 presymptomatic genetic testing to 100 individuals in two generations of 5 large BRCA1 families compared with service testing of 196 families since that time. Uptake was significantly higher in the first generation (group 1), who were directly offered testing, and much higher in females. Seventy-four percent of unaffected women in the first generation proceeded to testing, 42% of men. This decreased to 44% of women in the second generation (group 2) and 9% males (p = 0.0003). Uptake in unaffected individuals in the final group (group 3) with no proactive approach was significantly lower than that in the first group. Overall uptake after 10 years was 56% (95% confidence interval, CI, 50-62%) for group 1 and 36% (95% CI 34.3-37.7%) for 1084 group 3 individuals (p = 0.0003). Among women, uptake was 74% (95% CI 67-81%) in group 1 at 10 years compared with 51.5% (95% CI 49-54%) in 552 group 3 women (p = 0.023). In men, uptake was 42% (95% CI 33-52%) in group 1 and 21.1% (95% CI 18.1-23.1%) among 532 men in group 3 (p = 0.0098). Although these results are not from a randomized trial, they show particularly among men a substantially higher uptake of genetic services with a direct approach. Importance should be given to more proactive approaches to ensure that men in BRCA1/2-positive families receive the appropriate information.

Risk reducing mastectomy: outcomes in 10 European centres.

BACKGROUND: Increasingly women at high risk of breast cancer are opting for risk reducing surgery. The aim of this study was to assess the effectiveness of this approach in women at high risk in both carriers and non-carriers of BRCA1/2. METHODS: Data from 10 European centres that offer a genetic counselling and screening service to women at risk were obtained prospectively from 1995. Breast cancer risks were estimated from life tables and a control group of women at risk who did not undergo surgery. RESULTS: The combined centres have data on 550 women who have undergone risk reducing mastectomy with greater than 3334 women years of follow-up. Operations were carried out on women with lifetime risks of 25-80%, with an average expected incidence rate of 1% per year. No breast cancers have occurred in this cohort in the "at risk" unaffected breast, whereas >34 would have been expected. A high rate (2-3.6%) of occult disease was identified in the at risk breast at the time of surgery. INTERPRETATION: We conclude that risk reducing surgery is highly effective.

Probability of BRCA1/2 mutation varies with ovarian histology: results from screening 442 ovarian cancer families.

While there are many reports in the literature of mutation testing of BRCA1 and BRCA2 in breast/ovarian cancer families, the question of which type of ovarian cancers are relevant still pertains. We have undertaken whole gene screening including multiple ligation-dependent probe amplification in an affected individual within 442 unrelated non-Jewish families containing at least one reported ovarian cancer diagnosed less than 50 years or at any age with family history of breast or ovarian cancer for mutations in BRCA1 and BRCA2. A total of 166 mutations were identified 110 (25%) in BRCA1 and 56 (13%) in BRCA2. In families without confirmation of ovarian diagnosis, the detection rate drops significantly. In families fulfilling Breast Cancer Linkage Consortium (BCLC) criteria with confirmed ovarian cancer cases, the mutation detection frequency was 80%. If only BCLC families with unconfirmed ovarian cancers were included, the detection rate dropped to 36% when a relevant ovarian cancer diagnosis was not confirmed. In BCLC families containing only one ovarian cancer, BRCA2 accounted for 45% of identified mutations. No mutations were identified in affected individuals with borderline or mucinous tumours. Detection rates dropped below the 10/20% international thresholds in a number of families with unconfirmed ovarian cancers. Borderline/mucinous pathology substantially reduces the likelihood of identifying a BRCA1/2 mutation. Strenuous efforts should be made to confirm ovarian pathology if the lack of confirmation or refuting the diagnosis would decrease a family's likelihood of mutation detection below screening thresholds. In the UK, a higher proportion of families harbour BRCA2 pathogenic mutations than predicted from previous studies.

Molecular characterisation of SMARCB1 and NF2 in familial and sporadic schwannomatosis.

BACKGROUND: Schwannomatosis is a rare condition characterised by multiple schwannomas and lack of involvement of the vestibular nerve. A recent report identified bi-allelic mutations in the SMARCB1/INI1 gene in a single family with schwannomatosis. We aimed to establish the contribution of the SMARCB1 and the NF2 genes to sporadic and familial schwannomatosis in our cohort. METHODS: We performed DNA sequence and dosage analysis of SMARCB1 and NF2 in 28 sporadic cases and 15 families with schwannomatosis. RESULTS: We identified germline mutations in SMARCB1 in 5 of 15 (33.3%) families with schwannomatosis and 2 of 28 (7.1%) individuals with sporadic schwannomatosis. In all individuals with a germline mutation in SMARCB1 in whom tumour tissue was available, we detected a second hit with loss of SMARCB1. In addition, in all affected individuals with SMARCB1 mutations and available tumour tissue, we detected bi-allelic somatic inactivation of the NF2 gene. SMARCB1 mutations were associated with a higher number of spinal tumours in patients with a positive family history (p = 0.004). CONCLUSION: In contrast to the recent report where no NF2 mutations were identified in a schwannomatosis family with SMARCB1 mutations, in our cohort, a four hit model with mutations in both SMARCB1 and NF2 define a subset of patients with schwannomatosis.