Jewish cultural and religious factors and uptake of population-based BRCA testing across denominations: a cohort study.

OBJECTIVE: To evaluate the association of Jewish cultural and religious identity and denominational affiliation with interest in, intention to undertake and uptake of population-based BRCA (Breast Cancer Gene)-testing. DESIGN: Cohort-study set within recruitment to GCaPPS-trial (ISRCTN73338115). SETTING: London Ashkenazi-Jewish (AJ) population. POPULATION OR SAMPLE: AJ men and women, >18 years. METHODS: Participants were self-referred, and attended recruitment clinics (clusters) for pre-test counselling. Subsequently consenting individuals underwent BRCA testing. Participants self-identified to one Jewish denomination: Conservative/Liberal/Reform/Traditional/Orthodox/Unaffiliated. Validated scales measured Jewish Cultural-Identity (JI) and Jewish Religious-identity (JR). Four-item Likert-scales analysed initial 'interest' and 'intention to test' pre-counselling. Item-Response-Theory and graded-response models, modelled responses to JI and JR scales. Ordered/multinomial logistic regression modelling evaluated association of JI-scale, JR-scale and Jewish Denominational affiliation on interest, intention and uptake of BRCA testing. MAIN OUTCOME MEASURES: Interest, intention, uptake of BRCA testing. RESULTS: In all, 935 AJ women/men of mean age = 53.8 (S.D = 15.02) years, received pre-test education and counselling through 256 recruitment clinic clusters (median cluster size = 3). Denominational affiliations included Conservative/Masorti = 91 (10.2%); Liberal = 82 (9.2%), Reform = 135 (15.1%), Traditional = 212 (23.7%), Orthodox = 239 (26.7%); and Unaffiliated/Non-practising = 135 (15.1%). Overall BRCA testing uptake was 88%. Pre-counselling, 96% expressed interest and 60% intention to test. JI and JR scores were highest for Orthodox, followed by Conservative/Masorti, Traditional, Reform, Liberal and Unaffiliated Jewish denominations. Regression modelling showed no significant association between overall Jewish Cultural or Religious Identity with either interest, intention or uptake of BRCA testing. Interest, intention and uptake of BRCA testing was not significantly associated with denominational affiliation. CONCLUSIONS: Jewish religious/cultural identity and denominational affiliation do not appear to influence interest, intention or uptake of population-based BRCA testing. BRCA testing was robust across all Jewish denominations. TWEETABLE ABSTRACT: Jewish cultural/religious factors do not affect BRCA testing, with robust uptake seen across all denominational affiliations.

Randomised trial of population-based BRCA testing in Ashkenazi Jews: long-term outcomes.

OBJECTIVE: Unselected population-based BRCA testing provides the opportunity to apply genomics on a population-scale to maximise primary prevention for breast-and-ovarian cancer. We compare long-term outcomes of population-based and family-history (FH)/clinical-criteria-based BRCA testing on psychological health and quality of life. DESIGN: Randomised controlled trial (RCT) (ISRCTN73338115) GCaPPS, with two-arms: (i) population-screening (PS); (ii) FH/clinical-criteria-based testing. SETTING: North London Ashkenazi-Jewish (AJ) population. POPULATION/SAMPLE: AJ women/men. METHODS: Population-based RCT (1:1). Participants were recruited through self-referral, following pre-test genetic counselling from the North London AJ population. INCLUSION CRITERIA: AJ women/men >18 years old; exclusion-criteria: prior BRCA testing or first-degree relatives of BRCA-carriers. INTERVENTIONS: Genetic testing for three Jewish BRCA founder-mutations: 185delAG (c.68_69delAG), 5382insC (c.5266dupC) and 6174delT (c.5946delT), for (i) all participants in PS arm; (ii) those fulfilling FH/clinical criteria in FH arm. Linear mixed models and appropriate contrast tests were used to analyse the impact of BRCA testing on psychological and quality-of-life outcomes over 3 years. MAIN OUTCOME MEASURES: Validated questionnaires (HADS/MICRA/HAI/SF12) used to analyse psychological wellbeing/quality-of-life outcomes at baseline/1-year/2-year/3-year follow up. RESULTS: In all, 1034 individuals (691 women, 343 men) were randomised to PS (n = 530) or FH (n = 504) arms. There was a statistically significant decrease in anxiety (P = 0.046) and total anxiety-&-depression scores (P = 0.0.012) in the PS arm compared with the FH arm over 3 years. No significant difference was observed between the FH and PS arms for depression, health-anxiety, distress, uncertainty, quality-of-life or experience scores associated with BRCA testing. Contrast tests showed a decrease in anxiety (P = 0.018), health-anxiety (P < 0.0005) and quality-of-life (P = 0.004) scores in both PS and FH groups over time. Eighteen of 30 (60%) BRCA carriers identified did not fulfil clinical criteria for BRCA testing. Total BRCA prevalence was 2.9% (95% CI 1.97-4.12%), BRCA1 prevalence was 1.55% (95% CI 0.89-2.5%) and BRCA2 prevalence was 1.35% (95% CI 0.74-2.26%). CONCLUSION: Population-based AJ BRCA testing does not adversely affect long-term psychological wellbeing or quality-of-life, decreases anxiety and could identify up to 150% additional BRCA carriers. TWEETABLE ABSTRACT: Population BRCA testing in Ashkenazi Jews reduces anxiety and does not adversely affect psychological health or quality of life.

Attitude towards and factors affecting uptake of population-based BRCA testing in the Ashkenazi Jewish population: a cohort study.

OBJECTIVE: To evaluate factors affecting unselected population-based BRCA testing in Ashkenazi Jews (AJ). DESIGN: Cohort-study set within recruitment to the GCaPPS trial (ISRCTN73338115). SETTING: North London AJ population. POPULATION OR SAMPLE: Ashkenazi Jews women/men >18 years, recruited through self-referral. METHODS: Ashkenazi Jews women/men underwent pre-test counselling for BRCA testing through recruitment clinics (clusters). Consenting individuals provided blood samples for BRCA testing. Data were collected on socio-demographic/family history/knowledge/psychological well-being along with benefits/risks/cultural influences (18-item questionnaire measuring 'attitude'). Four-item Likert-scales analysed initial 'interest' and 'intention-to-test' pre-counselling. Uni- and multivariable logistic regression models evaluated factors affecting uptake/interest/intention to undergo BRCA testing. Statistical inference was based on cluster robust standard errors and joint Wald tests for significance. Item-Response Theory and graded-response models modelled responses to 18-item questionnaire. MAIN OUTCOME MEASURES: Interest, intention, uptake, attitude towards BRCA testing. RESULTS: A total of 935 individuals (women = 67%/men = 33%; mean age = 53.8 (SD = 15.02) years) underwent pre-test genetic-counselling. During the pre-counselling, 96% expressed interest in and 60% indicated a clear intention to undergo BRCA testing. Subsequently, 88% opted for BRCA testing. BRCA-related knowledge (P = 0.013) and degree-level education (P = 0.01) were positively and negatively (respectively) associated with intention-to-test. Being married/cohabiting had four-fold higher odds for BRCA testing uptake (P = 0.009). Perceived benefits were associated with higher pre-counselling odds for interest in and intention to undergo BRCA testing. Reduced uncertainty/reassurance were the most important factors contributing to decision-making. Increased importance/concern towards risks/limitations (confidentiality/insurance/emotional impact/inability to prevent cancer/marriage ability/ethnic focus/stigmatisation) were significantly associated with lower odds of uptake of BRCA testing, and discriminated between acceptors and decliners. Male gender/degree-level education (P = 0.001) had weaker correlations, whereas having children showed stronger (P = 0.005) associations with attitudes towards BRCA testing. CONCLUSIONS: BRCA testing in the AJ population has high acceptability. Pre-test counselling increases awareness of disadvantages/limitations of BRCA testing, influencing final cost-benefit perception and decision-making on undergoing testing. TWEETABLE ABSTRACT: BRCA testing in Ashkenazi Jews has high acceptability and uptake. Pre-test counselling facilitates informed decision-making.

Factors affecting uptake and adherence to breast cancer chemoprevention: a systematic review and meta-analysis.

BACKGROUND: Preventive therapy is a risk reduction option for women who have an increased risk of breast cancer. The effectiveness of preventive therapy to reduce breast cancer incidence depends on adequate levels of uptake and adherence to therapy. We aimed to systematically review articles reporting uptake and adherence to therapeutic agents to prevent breast cancer among women at increased risk, and identify the psychological, clinical and demographic factors affecting these outcomes. DESIGN: Searches were carried out in PubMed, CINAHL, EMBASE and PsychInfo, yielding 3851 unique articles. Title, abstract and full text screening left 53 articles, and a further 4 studies were identified from reference lists, giving a total of 57. This review was prospectively registered with PROSPERO (CRD42014014957). RESULTS: Twenty-four articles reporting 26 studies of uptake in 21 423 women were included in a meta-analysis. The pooled uptake estimate was 16.3% [95% confidence interval (CI) 13.6-19.0], with high heterogeneity (I(2) = 98.9%, P < 0.001). Uptake was unaffected by study location or agent, but was significantly higher in trials [25.2% (95% CI 18.3-32.2)] than in non-trial settings [8.7% (95% CI 6.8-10.9)] (P < 0.001). Factors associated with higher uptake included having an abnormal biopsy, a physician recommendation, higher objective risk, fewer side-effect or trial concerns, and older age. Adherence (day-to-day use or persistence) over the first year was adequate. However, only one study reported a persistence of ≥ 80% by 5 years. Factors associated with lower adherence included allocation to tamoxifen (versus placebo or raloxifene), depression, smoking and older age. Risk of breast cancer was discussed in all qualitative studies. CONCLUSION: Uptake of therapeutic agents for the prevention of breast cancer is low, and long-term persistence is often insufficient for women to experience the full preventive effect. Uptake is higher in trials, suggesting further work should focus on implementing preventive therapy within routine care.

Factors influencing uptake and timing of risk reducing salpingo-oophorectomy in women at risk of familial ovarian cancer: a competing risk time to event analysis.

OBJECTIVE: To evaluate factors affecting uptake of risk-reducing salpingo-oophorectomy (RRSO) over time in women at high-risk of familial ovarian cancer. DESIGN: Prospective observational cohort. SETTING: Tertiary high-risk familial gynaecological cancer clinic. POPULATION/SAMPLE: New clinic attendees between March 2004 and November 2009, fulfilling the high-risk criteria for the UK Familial Ovarian Cancer Screening Study. METHODS: Risk management options discussed included RRSO and ovarian surveillance. Outcome data were analysed from a bespoke database. The competing risk method was used to model the cumulative incidence function (CIF) of RRSO over time, and the sub-hazard ratio (SHR) was used to assess the strength of the association of variables of interest with RRSO. Gray's test was used to evaluate the difference in CIF between two groups and multivariable competing risk regression analysis was used to model the cumulative probabilities of covariates on the CIF. RESULTS: Of 1133 eligible women, 265 (21.4%) opted for RRSO and 868 (69.9%) chose screening. Women undergoing RRSO were older (49 years, interquartile range 12.2 years) than those preferring screening (43.4 years, interquartile range 11.9 years) (P < 0.0005). The CIF for RRSO at 5 years was 0.55 (95% CI 0.45-0.64) for BRCA1/2 carriers and 0.22 (95% CI 0.19-0.26) for women of unknown mutation status (P < 0.0001); 0.42 (95% CI 0.36-0.47) for postmenopausal women (P < 0.0001); 0.29 (95% CI 0.25-0.33) for parity ≥1 (P = 0.009) and 0.47 (95% CI 0.39-0.55) for a personal history of breast cancer (P < 0.0001). Variables of significance from the regression analysis were: a BRCA1/2 mutation (SHR 2.31, 95% CI 1.7-3.14), postmenopausal status (SHR 2.16, 95% CI 1.62-2.87)) and a personal history of breast cancer (SHR 1.5, 95% CI 1.09-2.06). CONCLUSIONS: Decision-making is a complex process and women opt for surgery many years after initial risk assessment. BRCA carriers, postmenopausal women and women who had breast cancer are significantly more likely to opt for preventative surgery.

Two cases of spinal tanycytic ependymomas occurring in brothers with a neurofibromatosis type 2 gene mutation.

Tanycytic ependymomas are a rare spinal cord tumour arising from tanycyte cells lining the ventricle or spinal central canal. This is the first report of familial spinal tanycytic ependymoma occurring in two first degree relatives. Both patients underwent surgical resection of the intra-medullary tumours with good overall recovery. Genetic analysis identified that the brothers shared a previously unreported mutation in the NF-2 gene. NF-2 mutations in spinal tanycytic ependymomas may be more common than initially thought and consideration should be given to screening the neural axis for other tumours and genetic counselling.

Outcome of risk-reducing salpingo-oophorectomy in BRCA carriers and women of unknown mutation status.

OBJECTIVE: To compare surgical outcomes and occult cancer rates at risk-reducing salpingo-oophorectomy in BRCA carriers and high-risk women who had not undergone genetic testing. DESIGN: Prospective cohort study. SETTING: Tertiary high-risk familial gynaecological cancer clinic. POPULATION: Women undergoing risk-reducing salpingo-oophorectomy between January 2005 and November 2009. METHODS: Women at high-risk of ovarian/tubal cancer were identified on the basis of the inclusion criteria for the UK Familial Ovarian Cancer Screening Study. Risk management options discussed with 1456 high-risk women included risk-reducing salpingo-oophorectomy. A strict histopathological protocol with serial slicing was used to assess tubes and ovaries. RESULTS: In total, 308 high-risk women (191 with unknown mutation status; 117 known BRCA1/BRCA2 carriers) chose risk-reducing surgery; 94.5% of procedures were performed laparoscopically. The surgical complication rate was 3.9% (95% CI 2.0-6.7). Four ovarian and ten tubal occult invasive/in situ cancers were found. The overall occult invasive cancer rate was 5.1% (95% CI 1.9-10.83) in BRCA1/BRCA2 carriers and 1.05% (95% CI 0.13-3.73) in untested women. When tubal in situ cancers were included, the overall rate was 4.55% (95% CI 2.5-7.5). Two untested women with tubal carcinoma in situ were subsequently found to be BRCA carriers. The median ages of BRCA carriers (58 years; IQR 13.4 years) and untested women (49.5 years; IQR 20.6 years) with occult invasive/in situ cancer were not significantly different (P = 0.454). CONCLUSIONS: Both high-risk women of unknown mutation status and BRCA carriers have a significant (although higher in the latter group) rate of occult invasive/in situ tubal/ovarian cancer, with a similar age distribution at detection. The data has important implications for counselling high-risk women on the likelihood of occult malignancy and perioperative complications at risk-reducing salpingo-oophorectomy. Women with occult disease should be offered genetic testing.

SPRED1 mutations (Legius syndrome): another clinically useful genotype for dissecting the neurofibromatosis type 1 phenotype.

OBJECTIVE: Mutations of the SPRED1 gene, one of a family of Sprouty (Spry)/Spred proteins known to "downregulate" mitogen activated protein kinase (MAPK) signalling, have been identified in patients with a mild neurofibromatosis type 1 (NF1) phenotype with pigmentary changes but no neurofibromas (Legius syndrome).To ascertain the frequency of SPRED1 mutations as a cause of this phenotype and to investigate whether other SPRED/SPRY genes may be causal, a panel of unrelated mild NF1 patients were screened for mutations of the SPRED1-3 and the SPRY1-4 genes. METHODS: 85 patients with a mild NF1 phenotype were screened for SPRED1 mutations. 44 patients negative for both NF1 and SPRED1 mutations were then screened for SPRED2-3 and SPRY1-4 mutations. Complexity analysis was applied to analyse the flanking sequences surrounding the identified SPRED1 mutations for the presence of direct and inverted repeats or symmetric sequence elements in order to infer probable mutational mechanism. RESULTS: SPRED1 mutations were identified in 6 cases; 5 were novel and included 3 nonsense (R16X, E73X, R262X), 2 frameshift (c.1048_c1049 delGG, c.149_1152del 4 bp), and a single missense mutation (V44D). Short direct or inverted repeats detected immediately adjacent to some SPRED1 mutations may have led to the formation of the microdeletions and base pair substitutions. DISCUSSION: The identification of SPRED1 gene mutation in NF1-like patients has major implications for counselling NF1 families.

A multidisciplinary team approach minimises prophylactic mastectomy rates.

BACKGROUND: Prophylactic mastectomy (PM) has become increasingly common but is not without complications especially if accompanied by reconstructive surgery. In patients with sporadic unilateral breast cancer, contralateral PM offers no survival advantage. Multidisciplinary team (MDT) communication and interaction may facilitate shared decision-making and curtail PM rates. The aim of this study was investigate the effect of a regional MDT meeting on PM decision-making. METHODS: We conducted an observational study involving retrospective review of prospectively recorded MDT meeting records for a 151 patient requests for PM from 2011 to 2014. Final MDT decisions were recorded as PM 'accepted', 'declined' or 'pending'. For MDT sanctioned requests, the factors justifying PM were recorded. Where PM was declined, justification for MDT refusal was sought and recorded. RESULTS: Approximately half of all requests for PM have been upheld (53.0%) and 1/3 of requests have been declined (32.5%). Of those declined, low risk of contralateral breast cancer versus relatively high risk of systemic relapse were commonly cited as justification for PM refusal (45.7%). A proportion of patients who initiated PM discussion subsequently changed their minds (19.6%), or failed to attend clinic appointments (6.5%). Some patients were deemed medically unfit for complex reconstructive surgery (13%), or were declined on the basis of an apparent cosmetic drive for surgery (6.5%), concerns regarding depression or anxiety (2.2%) and/or if family history could not be substantiated (6.5%). DISCUSSION: MDT meetings facilitate cross-specialty interrogation of requests for PM, minimise unnecessary surgery and restrict PM to those likely to derive maximum benefit.

Functional hyperactivity of monocytes after bone marrow transplantation: possible relevance for the development of post-transplant complications or relapse.

Bone marrow transplant (BMT) complications such as graft-versus-host disease (GVHD), veno-occlusive disease (VOD) and cytomegalovirus (CMV) infection are associated with high levels of circulating tumour necrosis factor-alpha (TNF), much of which may be monocyte derived. We therefore studied monocyte activation after BMT in 36 patients (18 allografts and 18 autografts); plasma neopterin and in vitro secretion of superoxide, neopterin and TNF by peripheral blood monocytes were assessed. Monocyte respiratory burst was raised at regeneration but returned to near-normal within 7 days. Plasma neopterin, and in vitro secretion of neopterin and TNF, were greater than twice normal at regeneration and remained raised for up to 6 weeks after BMT. Plasma neopterin was higher following allogeneic BMT than autologous BMT and was independent of GVHD or VOD. Low levels were seen in one patient who failed to engraft. There is evidence of increased activation of monocytes at the time of and for several weeks after engraftment post-BMT. Abnormal monocyte activation may predispose to, rather than result from, the development of complications in the early post-transplant period.

Hypercalcaemia due to calcium binding IgM paraprotein in Waldenström's macroglobulinaemia.

A case of Waldenström's macroglobulinaemia with asymptomatic hypercalcaemia is reported in which calcium binding to the paraprotein was found. This is the first report of this phenomenon in Waldenström's macroglobulinaemia and the first report of calcium binding to an IgM paraprotein.

Population-based, risk-stratified genetic testing for ovarian cancer risk: a focus group study.

STUDY PURPOSE: A population-based risk stratification programme for ovarian cancer (OC) may improve OC survival by identifying women at increased risk and implementing an appropriate risk management strategy. The present study explored attitudes towards an OC risk stratification programme incorporating predictive genetic testing and risk-stratified screening as part of a larger study investigating OC screening. METHODS: Focus groups consisting of 56 members of the general public (mean age 45 years; 34% non-white) were conducted using a hypothetical scenario. The group sessions were recorded, transcribed verbatim and analysed using Framework Analysis. RESULTS: There was strong support for the proposed programme. Genetic testing and risk-stratified screening was thought to raise awareness, offer reassurance and offer opportunities for early intervention. Anxiety was only mentioned in relation to receiving a diagnosis of OC and not with screening per se. Perhaps because lay models of cancer already embrace both environmental and genetic factors, a low-risk result was not anticipated to result in a false sense of immunity. Unexpectedly, participants also wanted to receive cancer prevention advice in conjunction with genetic testing; screening alone was not regarded as sufficient. CONCLUSION: The encouraging results from this small study warrant further large-scale research into risk-stratified OC screening.

Intramedullary tumours in patients with neurofibromatosis type 2: MRI features associated with a favourable prognosis.

AIM: To assess the magnetic resonance imaging (MRI) features and natural history of intramedullary tumours in patients with neurofibromatosis type 2 (NF2). MATERIALS AND METHODS: Eleven NF2 patients with intramedullary spinal cord tumours were identified from the database of the multidisciplinary NF2 clinic. All the imaging studies of these patients were individually reviewed by two neuroradiologists to evaluate the size, number, location, imaging characteristics, and interval growth of the intramedullary tumours. RESULTS: Two of the 11 patients had lesions that required surgery. Both these lesions were in the cervical region, and extended over three and five segments respectively. Nine patients with a mean imaging follow-up period of 77 months had lesions that remained stable, apart from the development of small peritumoral cysts in three. The lesions were well circumscribed, often multiple, usually less than 1cm in diameter, and were most frequently found in the cervical cord. CONCLUSION: The majority of intramedullary tumours in NF2 patients are very slow growing and share certain MRI features that differ from those of progressive or symptomatic lesions.

An absence of cutaneous neurofibromas associated with a 3-bp inframe deletion in exon 17 of the NF1 gene (c.2970-2972 delAAT): evidence of a clinically significant NF1 genotype-phenotype correlation.

Neurofibromatosis type 1 (NF1) is characterized by cafe-au-lait spots, skinfold freckling, and cutaneous neurofibromas. No obvious relationships between small mutations (<20 bp) of the NF1 gene and a specific phenotype have previously been demonstrated, which suggests that interaction with either unlinked modifying genes and/or the normal NF1 allele may be involved in the development of the particular clinical features associated with NF1. We identified 21 unrelated probands with NF1 (14 familial and 7 sporadic cases) who were all found to have the same c.2970-2972 delAAT (p.990delM) mutation but no cutaneous neurofibromas or clinically obvious plexiform neurofibromas. Molecular analysis identified the same 3-bp inframe deletion (c.2970-2972 delAAT) in exon 17 of the NF1 gene in all affected subjects. The Delta AAT mutation is predicted to result in the loss of one of two adjacent methionines (codon 991 or 992) ( Delta Met991), in conjunction with silent ACA-->ACG change of codon 990. These two methionine residues are located in a highly conserved region of neurofibromin and are expected, therefore, to have a functional role in the protein. Our data represent results from the first study to correlate a specific small mutation of the NF1 gene to the expression of a particular clinical phenotype. The biological mechanism that relates this specific mutation to the suppression of cutaneous neurofibroma development is unknown.

Homozygous inactivation of the NF1 gene in bone marrow cells from children with neurofibromatosis type 1 and malignant myeloid disorders.

BACKGROUND: The risk of malignant myeloid disorders in young children with neurofibromatosis type 1 is 200 to 500 times the normal risk. The gene for neurofibromatosis type 1 (NF1) encodes neurofibromin, a protein that negatively regulates signals transduced by Ras proteins. Genetic and biochemical data support the hypothesis that NF1 functions as a tumor-suppressor gene in immature myeloid cells, but inactivation of both NF1 alleles has not been demonstrated in leukemic cells from patients with neurofibromatosis type 1. METHODS: Using an in vitro transcription and translation system, we screened bone marrow samples from 18 children with neurofibromatosis type 1 and myeloid disorders for NF1 mutations that cause a truncated protein. Mutations were confirmed by direct sequencing of genomic DNA from the patients, and from their affected parents, in cases of familial neurofibromatosis type 1. RESULTS: Specimens from 9 of the 18 children contained abnormal peptide fragments, and truncating mutations of the NF1 gene were found in specimens from 8 of these children. The normal NF1 allele was absent in bone marrow samples from five of the eight children. We detected the same mutation in DNA from the affected parent of each child with familial neurofibromatosis type 1. CONCLUSIONS: Both alleles of the NF1 gene are inactivated in leukemic cells in some patients with neurofibromatosis type 1. NF1 appears to function as a tumor-suppressor gene in immature myeloid cells.

Mutations of the NF1 gene in children with juvenile myelomonocytic leukemia without clinical evidence of neurofibromatosis, type 1.

Juvenile myelomonocytic leukemia (JMML) is a pediatric myelodysplastic syndrome that is associated with neurofibromatosis, type 1 (NF1). The NF1 tumor suppressor gene encodes neurofibromin, which regulates the growth of immature myeloid cells by accelerating guanosine triphosphate hydrolysis on Ras proteins. The purpose of this study was to determine if the NF1 gene was involved in the pathogenesis of JMML in children without a clinical diagnosis of NF1. An in vitro transcription and translation system was used to screen JMML marrows from 20 children for NF1 mutations that resulted in a truncated protein. Single-stranded conformational polymorphism analysis was used to detect RAS point mutations in these samples. We confirmed mutations of NF1 in three leukemias, one of which also showed loss of the normal NF1 allele. An NF1 mutation was detected in normal tissue from the only patient tested and this suggests that JMML may be the presenting feature of NF1 in some children. Activating RAS mutations were found in four patients; as expected, none of these samples harbored NF1 mutations. Because 10% to 14% of children with JMML have a clinical diagnosis of NF1, these data are consistent with the existence of NF1 mutations in approximately 30% of JMML cases.