A molecular analysis of individuals with neurofibromatosis type 1 (NF1) and optic pathway gliomas (OPGs), and an assessment of genotype-phenotype correlations.

BACKGROUND: Neurofibromatosis type 1 (NF1) affects 1 in 2500 people, and 15% of these may develop an optic pathway glioma (OPG). OPGs behave differently in NF1, and, given their frequency, surveillance is important. However, this is difficult because of the additional complications these patients may have, such as learning difficulties. Management is also different given that NF1 results from loss of function of tumour suppressor gene. A genotype-phenotype correlation may help to determine who is at risk of developing these tumours, aid focused screening, and shed light on response to treatments. METHODS: As part of a long-term follow-up study of patients with NF1 OPGs, the authors assessed genotype-phenotype correlation. Fluorescein in situ hybridisation was performed to identify large deletions, and then a full gene screen for mutations, by denaturing high-performance liquid chromatography. RESULTS: 80 patients with NF1 OPGs were identified, and molecular analyses were performed in a subset of 29. A clustering of pathogenic changes in the 5' tertile of the gene was found. The authors combined these results with those for another two NF1 OPG cohorts and collectively found the same trend. When compared with a control population of NF1 patients without an OPG, the OR of a mutation being present in the 5' tertile was 6.05 (p=0.003) in the NF1 OPG combined cohorts. CONCLUSION: It is possible that genotype is a significant determinant of the risk of development of OPGs in NF1.

Empirical development of improved diagnostic criteria for neurofibromatosis 2.

PURPOSE: Four sets of clinical diagnostic criteria have been proposed for neurofibromatosis 2, but all have low sensitivity at the time of initial clinical assessment for the disease among patients with a negative family history who do not present with bilateral vestibular schwannomas. We have empirically developed and tested an improved set of diagnostic criteria that uses current understanding of the natural history and genetic characteristics of neurofibromatosis 2 to increase sensitivity while maintaining very high specificity. METHODS: We used data from the UK Neurofibromatosis 2 Registry and Kaplan-Meier curves to estimate frequencies of clinical features at various ages among patients with or without unequivocal neurofibromatosis 2. On the basis of this analysis, we developed the Baser criteria, a new diagnostic system that incorporates genetic testing and gives more weight to the most characteristic features and to those that occur before 30 years of age. RESULTS: In an independent validation subset of patients with unequivocal neurofibromatosis 2, the Baser criteria increased diagnostic sensitivity to 79% (9-15% greater than previous sets of criteria) while maintaining 100% specificity at the age at onset of the first characteristic sign of neurofibromatosis 2. CONCLUSION: The Baser criteria permit early diagnosis in a greater proportion of patients with neurofibromatosis 2 than previous sets of diagnostic criteria.

Breast cancer susceptibility variants alter risks in familial disease.

BACKGROUND: Recent candidate and genome-wide association studies have identified variants altering susceptibility to breast cancer. OBJECTIVE: To establish the relevance of these variants to breast cancer risk in familial breast cancer cases both with and without BRCA1 or BRCA2 (BRCA1/2) mutations. METHODS: A cohort of unrelated individuals with breast cancer due to the presence of either BRCA1 (121) or BRCA2 mutations (109) and individuals with familial breast cancer not due to BRCA1/2 mutations (722) were genotyped using Taqman SNP Genotyping Assays. Allele frequencies were compared with an ethnically and gender-matched group (436). RESULTS: A synonymous variant (Ser51) in TOX3 (previously TNRC9) was associated with an increased risk of breast cancer (OR=1.82, p<0.001) in BRCA2 mutation carriers. The associations for FGFR2 (OR=1.20, p=0.046), TOX3 (OR=1.5, p<0.001), MAP3K1 (OR=1.26 p=0.03), CASP8 (OR=0.73 p=0.02) and the chromosome 8-associated SNP (OR=1.31, p=0.004) were replicated in individuals without BRCA1/2 mutations. In addition, homozygote carriers of MAP3K1 variants were shown to have a significantly lower Manchester Score (mean 13.8-17.6, p=0.003), whereas individuals carrying one or two copies of the FGFR2 variant had a higher Manchester Score (mean 17.5-17.9, p=0.01). CONCLUSIONS: This study confirms that susceptibility variants in FGFR2, TOX3 and MAP3K1 and on chromosome 8q are all associated with increased risk of cancer in individuals with a family history of breast cancer, whereas CASP8 is protective in this context. The level of risk is dependent on the strength of the family history and the presence of a BRCA1/2 mutation and contributes to the understanding of the use of these variants in clinical risk prediction.

Impaired tamoxifen metabolism reduces survival in familial breast cancer patients.

PURPOSE: Tamoxifen has been the mainstay adjuvant hormonal treatment for breast cancer for many years. Conversion of tamoxifen to its active metabolite, endoxifen, is reduced by low activity of the cytochrome P450 enzyme, CYP2D6. We examined the effect of reduced CYP2D6 activity on the response to tamoxifen in patients with familial early-onset breast cancer. EXPERIMENTAL DESIGN: We conducted a case note review and genotyping for the CYP2D6*3, CYP2D6*4, CYP2D6*5, and CYP2D6*41 alleles in 115 patients (47 BRCA1, 68 BRCA2) with familial breast cancer who had been treated with 20-mg tamoxifen following surgery. RESULTS: Eight (7%) individuals had genotypes consistent with poor metabolizer status, and 4 (3.5%) individuals took CYP2D6 inhibitor drugs concomitant with their tamoxifen and were also considered poor metabolizer. Time to tumor recurrence, disease-free survival, and overall survival were reduced in the patient group with poor metabolizer CYP2D6 activity. However, a significant effect was confined to patients with BRCA2 mutations with a worse overall survival (median survival, 7 versus 28 years; P = 0.008; adjusted hazard ratio, 9.7). CONCLUSIONS: Poor metabolizer status for CYP2D6 predicts worse overall survival in patients with familial breast cancer. Therefore, CYP2D6 inhibitor drugs should not be prescribed concomitantly with tamoxifen. Prospective studies should be undertaken to establish the effect of CYP2D6 status on outcome in familial breast cancer patients treated with tamoxifen.

Better life expectancy in women with BRCA2 compared with BRCA1 mutations is attributable to lower frequency and later onset of ovarian cancer.

PURPOSE: No formal assessment of life expectancy in women with BRCA1 and BRCA2 mutations in these genes has been reported previously. We have evaluated life expectancy using actuarial analysis and assessed the effect of breast and ovarian cancers on premature death in >1,000 BRCA1/2 carriers. METHODS: Families with pathogenic mutations in BRCA1 and BRCA2 have been ascertained in a 10-million population region of United Kingdom since 1996. Mutation carriers and their first-degree relatives were used in an analysis of breast and ovarian cancer incidence and mortality as well as to derive and compare an actuarial assessment of life expectancy. RESULTS: Six hundred twelve BRCA1 and 482 BRCA2 female mutation carriers were identified from 482 families. Life expectancy was significantly reduced for BRCA1 carriers compared with BRCA2 (P = 0.0002). This effect was attributable to an increased death rate from ovarian cancer (P = 0.04). Kaplan-Meier analysis revealed a better long-term survival from early-stage ovarian cancer in BRCA2 carriers but no significant differences in deaths from breast cancer or from women presenting with late-stage ovarian cancer. There was no other major contributing cause to death other than breast/ovarian cancer in BRCA1/2 female carriers. CONCLUSION: Interventions to reduce ovarian cancer incidence are likely to have a greater effect on life expectancy in BRCA1 compared with BRCA2 carriers.

Penetrance estimates for BRCA1 and BRCA2 based on genetic testing in a Clinical Cancer Genetics service setting: risks of breast/ovarian cancer quoted should reflect the cancer burden in the family.

BACKGROUND: The identification of a BRCA1 or BRCA2 mutation in familial breast cancer kindreds allows genetic testing of at risk relatives. However, considerable controversy exists regarding the cancer risks in women who test positive for the family mutation. METHODS: We reviewed 385 unrelated families (223 with BRCA1 and 162 with BRCA2 mutations) ascertained through two regional cancer genetics services. We estimated the penetrance for both breast and ovarian cancer in female mutation carriers (904 proven mutation carriers - 1442 females in total assumed to carry the mutation) and also assessed the effect on penetrance of mutation position and birth cohort. RESULTS: Breast cancer penetrance to 70 and to 80 years was 68% (95%CI 64.7-71.3%) and 79.5% (95%CI 75.5-83.5%) respectively for BRCA1 and 75% (95%CI 71.7-78.3%) and 88% (95%CI 85.3-91.7%) for BRCA2. Ovarian cancer risk to 70 and to 80 years was 60% (95%CI 65-71%) and 65% (95%CI 75-84%) for BRCA1 and 30% (95%CI 25.5-34.5%) and 37% (95%CI 31.5-42.5%) for BRCA2. These risks were borne out by a prospective study of cancer in the families and genetic testing of unaffected relatives. We also found evidence of a strong cohort effect with women born after 1940 having a cumulative risk of 22% for breast cancer by 40 years of age compared to 8% in women born before 1930 (p = 0.0005). CONCLUSION: In high-risk families, selected in a genetics service setting, women who test positive for the familial BRCA1/BRCA2 mutation are likely to have cumulative breast cancer risks in keeping with the estimates obtained originally from large families. This is particularly true for women born after 1940.

What are the implications in individuals with unilateral vestibular schwannoma and other neurogenic tumors?

OBJECTIVES: Individuals who develop a unilateral vestibular schwannoma (VS) and other neurogenic tumors are at high risk of having the inherited condition neurofibromatosis Type 2 (NF2). The risk of bilateral disease and transmission risk to offspring are important in surgical planning and counseling. The authors have attempted to resolve these risks. METHODS: A large NF2 dataset was interrogated for individuals who had initially presented with a unilateral VS and other tumors before developing bilateral disease, to assess the contralateral and offspring risks. RESULTS: Ninety-six patients with a unilateral VS and additional neurogenic tumors had a bilaterality rate of 48% at 20 years in those initially diagnosed when > 18 years of age and 82% if presenting earlier. Constitutional NF2 mutations were found in blood in 25 (27%) of 92, but 13 (76%) of 17 patients presenting with unilateral VS at < or = 18 years of age. Tumor analysis suggests that the vast majority of the remainder are mosaic for an NF2 mutation. CONCLUSIONS: Patients with unilateral VS and other NF2-related tumors who fulfill Manchester criteria have a high risk of developing a contralateral tumor, especially if presenting in childhood. Transmission risks are reduced for offspring, particularly in the older patients who are likely to be mosaic.

Adult weight gain and central obesity in women with and without a family history of breast cancer: a case control study.

Adult weight gain and central obesity can increase breast cancer risk. We determined the prevalence of adult weight gain and central obesity amongst women with a family history (FH) as compared to women with a population risk to determine whether adiposity could contribute to their increased risk. Adult weight gain, waist and waist:hip ratio (WHR) were determined amongst 475 women (aged 20-60 years) attending a regional FH breast cancer risk clinic, compared to 312 age matched women at population risk. Patterns of adult weight gain did not differ between women with and without a FH of breast cancer. The majority of weight gain occurred between the ages of 20 and 40 in both groups. Mean (sd) weight gain for women aged >40 years with a FH was 8.9 (10.3) kg compared to 9.1 (10.6) kg for controls (p = 0.85). Women with a FH had a significantly greater waist and WHR than controls. Mean (sd) waist was 83.7 (13) cm compared to 81.6 (11.3) cm for controls (p < 0.01). Mean (sd) WHR was 0.82 (0.1) compared to 0.80 (0.1) for controls (p < 0.01). FH of breast cancer was an independent predictor of having a WHR of >0.85; odds ratio (95% CI) = 1.42 (1.01-2.01) (p = 0.044). Significant weight gain between the ages of 20 and 40 and the prevalence of central obesity amongst FH women suggest the need for weight management within FH clinics.

Screening for familial ovarian cancer: failure of current protocols to detect ovarian cancer at an early stage according to the international Federation of gynecology and obstetrics system.

PURPOSE: To assess the effectiveness of annual ovarian cancer screening (transvaginal ultrasound and serum CA-125 estimation) in detecting presymptomatic ovarian cancer in women at increased genetic risk. PATIENTS AND METHODS: A cohort of 1,110 women at increased risk of ovarian cancer were screened between January 1991 and March 2004; 553 were moderate-risk individuals (4% to 10% lifetime risk) and 557 were high-risk individuals (> 10% lifetime risk). Outcome measurements include the number and stage of screen-detected cancers, the number and stage of cancers not detected at screening, the number of equivocal screening results requiring recall/repetition, and the number of women undergoing surgery for benign disease. RESULTS: Thirteen epithelial ovarian malignancies (12 invasive and one borderline), developed in the cohort. Ten tumors were detected at screening: three International Federation of Gynecology and Obstetrics (FIGO) stage I (including borderline), two stage II, four stage III, and one stage IV. Of the three cancers not detected by screening, two were stage III and one was stage IV; 29 women underwent diagnostic surgery but were found not to have ovarian cancer. CONCLUSION: Annual surveillance by transvaginal ultrasound scanning and serum CA-125 measurement in women at increased familial risk of ovarian cancer is ineffective in detecting tumors at a sufficiently early stage to influence prognosis. With a positive predictive value of 17% and a sensitivity of less than 50%, the performance of ultrasound does not satisfy the WHO screening standards. In addition, the combined protocol has a particularly high false-positive rate in premenopausal women, leading to unnecessary surgical intervention.

Parity and breast cancer risk among BRCA1 and BRCA2 mutation carriers.

INTRODUCTION: Increasing parity and age at first full-term pregnancy are established risk factors for breast cancer in the general population. However, their effects among BRCA1 and BRCA2 mutation carriers is still under debate. We used retrospective data on BRCA1 and BRCA2 mutation carriers from the UK to assess the effects of parity-related variables on breast cancer risk. METHODS: The data set included 457 mutation carriers who developed breast cancer (cases) and 332 healthy mutation carriers (controls), ascertained through families seen in genetic clinics. Hazard ratios were estimated by using a weighted cohort approach. RESULTS: Parous BRCA1 and BRCA2 mutation carriers were at a significantly lower risk of developing breast cancer (hazard ratio 0.54, 95% confidence interval 0.37 to 0.81; p = 0.002). The protective effect was observed only among carriers who were older than 40 years. Increasing age at first live birth was associated with an increased breast cancer risk among BRCA2 mutation carriers (p trend = 0.002) but not BRCA1 carriers. However, the analysis by age at first live birth was based on small numbers. CONCLUSION: The results suggest that the relative risks of breast cancer associated with parity among BRCA1 and BRCA2 mutation carriers may be similar to those in the general population and that reproductive history may be used to improve risk prediction in carriers.

BRCA1, BRCA2 and TP53 mutations in very early-onset breast cancer with associated risks to relatives.

Pathological mutations in BRCA1, BRCA2 and TP53 are associated with an increased risk of breast cancer. This study evaluated mutation frequency of these genes in early-onset breast cancer patients, and correlated this with family history and determined relative risks to family members. Patients with breast adenocarcinoma diagnosed 30 years were ascertained between 1980 and 1997. Family history was established and mutation screening of BRCA1, BRCA2 and TP53 genes was performed. Estimates of penetrance and relative risk were undertaken. DNA was obtained from 100/139 women. 17/36 familial cases had a BRCA1, BRCA2 or TP53 mutation. Of 64 non-familial cases, one BRCA2, two BRCA1 and two TP53 mutations were detected. Penetrance estimates (by age 70) for breast cancer were 84% for BRCA1 mutations and 91% for BRCA2 mutations and for ovarian cancer, 60% and 26%, respectively. Relative risks associated with mutations were consistent with previous studies. BRCA1 and BRCA2 mutations in patients with breast cancer 30 years are predicted strongly by family history. The majority of families with ovarian cancer were due to mutations in BRCA1/2 whereas these mutations only accounted for 30-50% of the excess breast cancers.

BRCA1/2 predictive testing: a study of uptake in two centres.

Differences in reported uptake of genetic testing for mutations in BRCA1 and BRCA2 can largely be accounted for by different methodologies and by studying research vs nonresearch families. In our joint study of 75 nonresearch families from two UK centres in which at least 3 years had elapsed since the initial proband had been informed of the availability of testing, only 45 and 34% of eligible individuals from Manchester and London, respectively, had come forward for counselling. Final uptake rates using a non-proactive approach were 53 and 29% for women and 11-12% for men, but the figure among those attending clinic was 73 and 62%, respectively. Unlike previous studies, we did not find that uptake had stabilised after a year with 25% of those being tested more than 2 years after the family was informed, and several delaying a considerable time between genetics appointments. We believe that the particularly low uptake even of counselling in men may need to be addressed by improving family communication or providing information sheets for family members to disseminate.

Basal cell carcinomas in gorlin syndrome: a review of 202 patients.

Gorlin syndrome (Naevoid Basal Cell Carcinoma Syndrome) is a rare autosomal dominant syndrome caused by mutations in the PTCH gene with a birth incidence of approximately 1 in 19,000. Patients develop multiple basal cell carcinomas of the skin frequently in early life and also have a predisposition to additional malignancies such as medulloblastoma. Gorlin Syndrome patients also have developmental defects such as bifid ribs and other complications such as jaw keratocysts. We studied the incidence and frequency of basal cell carcinomas in 202 Gorlin syndrome patients from 62 families and compared this to their gender and mutation type. Our data suggests that the incidence of basal cell carcinomas is equal between males and females and the mutation type cannot be used to predict disease burden.

Risk-reducing surgery for ovarian cancer: outcomes in 300 surgeries suggest a low peritoneal primary risk.

Risk-reducing salpingo-oophorectomy is currently advocated for the reduction of both breast and ovarian cancer risk in BRCA1/2 carriers, but residual risk of peritoneal primary cancer remains a concern. A sequential series of women attending a single institution for ovarian risk management underwent either risk-reducing surgery or screening. A person-years at risk analysis was used to compare observed versus expected cancers. In total, 300 women underwent risk-reducing salpingo-oophorectomy, including 160 BRCA1/2 mutation carriers. Three occult ovarian cancers were detected at surgery. There have been 2400.4 years of follow-up and 15.79 expected cancers. No peritoneal cancers have occurred. Amongst 503 women controls with 3444.3 years of follow-up, 15.93 ovarian cancers were expected and 17 were found. There were six ovarian cancer-related deaths in the control group compared with one in the surgery group. Risk-reducing salpingo-oophorectomy in a single institution has so far avoided peritoneal cancer incidence.

Uptake of risk-reducing surgery in unaffected women at high risk of breast and ovarian cancer is risk, age, and time dependent.

PURPOSE: The uptake of risk-reducing surgery in women at increased risk of breast and ovarian cancer is highly variable between countries and centers within countries. We have investigated the rate, timing, and age of uptake of surgery in the northwest of England to report the results after up to 7 years in a Regional Genetics center. METHODS: Uptake was documented in 211 known unaffected BRCA1/2 mutation carriers from 509 families and in 3,515 women at >25% lifetime risk of breast cancer without known mutations. RESULTS: Of the 211 mutation carriers, 40% opted for bilateral risk-reducing mastectomy (BRRM) and 45% underwent bilateral risk-reducing salpingo-oophorectomy (BRRSPO). Uptake of BRRM was significantly related to lifetime risk and age but continued over several years. In women not known to carry a BRCA mutation, 6.4% of women at 40% to 45% lifetime risk, 2.5% of women at 33% to 39% lifetime risk, and 1.8% of women at 25% to 32% lifetime risk underwent BRRM (P < 0.005). BRRSPO uptake was greater in BRCA1 (52%) than BRCA2 (28%) carriers but in both groups tended to occur within the first 2 years after gene test (except in the youngest age group) and in women between the ages of 35 and 45. CONCLUSION: To truly assess the uptake of risk-reducing surgery, longer-term follow-up is necessary particularly in younger women who are likely to delay BRRSPO. Careful risk counseling does seem to influence women's decisions for surgery, although the effect is not immediate.

Bayesian evaluation of breast cancer screening using data from two studies.

The mean sojourn time (the duration of the period during which a cancer is symptom free but potentially detectable by screening) and the screening sensitivity (the probability that a screen applied to a cancer in the preclinical screen detectable period will result in a positive diagnosis) are two important features of a cancer screening programme. Little data from any single study are available on the potential effectiveness of mammographic screening for breast cancer in women with a family history of the disease, despite this being an important public health issue. We develop a method of estimation, from two separate studies, of the two parameters, assuming that transition from no disease to preclinical screen detectable disease, and from preclinical disease to clinical disease, are Poisson processes. Estimation is performed by a Markov chain Monte Carlo algorithm. The method is applied to the synthesis of two studies of mammographic screening in women with a family history of breast cancer, one in Manchester and one in Kopparberg, Sweden.