Histopathological features of 'BRCAX' familial breast cancers in the kConFab resource

AIMS: In recent years histopathology has made an important contribution to the study of familial breast cancer, largely on the basis of the distinctive cancer phenotype commonly identified in BRCA1-mutation carriers. The aim of this study was to identify this phenotype amongst index cases from families in the kConFab familial breast cancer resource with no known pathogenic mutation ('BRCAX' families). METHODS: The histopathology of breast cancer from 180 individuals was reviewed: 132 members of individual BRCAX families, 26 BRCA1 and 15 BRCA2 mutation carriers and seven mutation negative individuals from families with a known pathogenic mutation. RESULTS: BRCAX breast cancers were a heterogeneous group with 25.8% grade 1, 37.9% grade 2 and 36.4% grade 3. Overall, 45/180 (25%) cases were designated 'BRCA1-phenotype' including 22/132 (16.7%) BRCAX cases, 18/26 (69.2%) BRCA1 and 5/15 (33.3%) BRCA2 mutation carriers. For BRCAX cases, a BRCA1 phenotype designation was negatively correlated with age. CONCLUSIONS: Characteristic breast cancer pathology is not diagnostic of a germline BRCA1 mutation, but it does indicate a pathogenic mechanism that occurs with increased frequency in BRCA1 mutation carriers. In BRCAX families, BRCA1 tumour phenotype may signal the presence of an unidentified BRCA1 mutation. However, this finding must be interpreted with regard to limits of the association between histopathology and genotype, and the importance of clinical context.     

Breast cancer after bilateral risk-reducing mastectomy

This study aims to evaluate the incidence of breast cancer after risk-reducing mastectomy (RRM) in healthy BRCA mutation carriers. This study is a long-term follow-up of 307 BRCA mutation carriers of whom 96 chose RRM. None of the study participants had a previous history of breast or ovarian cancer nor had they undergone RRM or risk-reducing bilateral salpingo-oophorectomy (BSO) prior to the time of BRCA testing. The annual incidence of post-mastectomy breast cancer was 0.8% compared with 1.7% in the non-operated group. Implications of these findings in relation to genetic counseling and future management are discussed.     

BRCA1 mutations in Algerian breast cancer patients: high frequency in young, sporadic cases

Breast cancer rates and median age of onset differ between Western Europe and North Africa. In Western populations, 5 to 10 % of breast cancer cases can be attributed to major genetic factors such as BRCA1 and BRCA2, while this attribution is not yet well defined among Africans. To help determine the contribution of BRCA1 mutations to breast cancer in a North African population, we analysed genomic DNA from breast cancer cases ascertained in Algiers. Both familial cases (at least three breast cancers in the same familial branch, or two with one bilateral or diagnosed before age 40) and sporadic cases less than 38 years of age were studied. Complete sequencing plus quantitative analysis of the BRCA1 gene was performed. 9.8 % (5/51) of early-onset sporadic and 36.4 % (4/11) of familial cases were found to be associated with BRCA1 mutations. This is in contrast 10.3 % of French HBOC families exhibiting a BRCA1 mutation. One mutation, c.798_799delTT, was observed in two Algerian families and in two families from Tunisia, suggesting a North African founder allele. Algerian non-BRCA1 tumors were of significantly higher grade than French non-BRCA tumors, and the age at diagnosis for Algerian familial cases was much younger than that for French non-BRCA familial cases. In conclusion, we observed a much higher frequency of BRCA1 mutations among young breast cancer patients than observed in Europe, suggesting biological differences and that the inclusion criterea for analysis in Western Europe may not be applicable for the Northern African population.     

Mutations predisposing to breast cancer in 12 candidate genes in breast cancer patients from Poland

A number of genes other than BRCA1 and BRCA2 have been associated with breast cancer predisposition, and extended genetic testing panels have been proposed. It is of interest to establish the full spectrum of deleterious mutations in women with familial breast cancer.We performed whole‐exome sequencing of 144 women with familial breast cancer and negative for 11 Polish founder mutations in BRCA1, CHEK2 and NBS1, and we evaluated the sequences of 12 known breast cancer susceptibility genes. A truncating mutation in a breast cancer gene was detected in 24 of 144 women (17%) with familial breast cancer. A BRCA2 mutation was detected in 12 cases, a (non‐founder) BRCA1 mutation was detected in 5 cases, a PALB2 mutation was detected in 4 cases and an ATM mutation was detected in 2 cases. Polish women with familial breast cancer who are negative for founder mutations in BRCA1, CHEK2 and NBS1 should be fully screened for mutations in BRCA1, BRCA2 and PALB2. The PALB2 founder mutation c.509_519delGA should be included in the panel of Polish founder mutations.     

Prevalence of founder mutations in the BRCA1 and BRCA2 genes among unaffected women from the Bahamas

Population‐based testing for BRCA1/2 mutations detects a high proportion of carriers not identified by cancer family history‐based testing. We sought to determine whether population‐based testing is an effective approach to genetic testing in the Bahamas, where 23% of women with breast cancer carry one of seven founder mutations in the BRCA1 or BRCA2 gene. We determined the prevalence of founder BRCA mutations in 1847 Bahamian women without a personal history of breast or ovarian cancer, unselected for age or family history. We found that 2.8% (20/705) of unaffected women with a family history of breast/ovarian cancer and 0.09% (1/1089) of unaffected women without a family history carry a BRCA mutation. A total of 38% of unaffected women with a known mutation in the family were found to carry the familial mutation. We previously suggested that all Bahamian women with breast or ovarian cancer be offered genetic testing. These current data suggest that additionally all unaffected Bahamian women with a family history of breast/ovarian cancer should be offered genetic testing for the founder BRCA mutations.     

Patient satisfaction and cancer‐related distress among unselected Jewish women undergoing genetic testing for BRCA1 and BRCA2

Metcalfe KA, Poll A, Llacuachaqui M, Nanda S, Tulman A, Mian N, Sun P, Narod SA. Patient satisfaction and cancer‐related distress among unselected Jewish women undergoing genetic testing for BRCA1 and BRCA2. It is not known to what extent participation in a genetic testing program for BRCA1 and BRCA2, which does not include an extensive pre‐test counselling session, influences cancer‐related distress, cancer risk perception and patient satisfaction. Unselected Jewish women in Ontario were offered genetic testing for three common Jewish BRCA mutations. Before testing and 1‐year post‐testing, the women completed questionnaires which assessed cancer‐related distress, cancer risk perception, and satisfaction. A total of 2080 women enrolled in the study; of these, 1516 (73%) completed a 1‐year follow‐up questionnaire. In women with a BRCA mutation, the mean breast cancer risk perception increased from 41.1% to 59.6% after receiving a positive genetic test result (p = 0.002). Among non‐carriers, breast cancer risk perception decreased slightly, from 35.8% to 33.5% (p = 0.08). The mean level of cancer‐related distress increased significantly for women with a BRCA mutation, but did not change in women without a mutation; 92.8% expressed satisfaction with the testing process. The results of this study suggest that the majority of Jewish women who took part in population genetic screening for BRCA1 and BRCA2 were satisfied with the delivery of genetic testing and would recommend testing to other Jewish women. However, women with a BRCA mutation experienced increased levels of cancer‐related distress.     

Application of BRCA1 and BRCA2 mutation carrier prediction models in breast and/or ovarian cancer families of French Canadian descent

The BRCAPRO, Couch, Myriad I and II, Ontario Family History Assessment Tool (FHAT), and Manchester models have been used to predict BRCA1 or BRCA2 mutation carrier status of women at high risk for developing the heritable form of breast and ovarian cancers. We have evaluated these models for their accuracy in classifying 224 French Canadian families with at least three cases of breast cancer (diagnosed before the age of 65 years), ovarian cancer, or male breast cancer where mutation status was known for an index affected case used to assess the model. This series includes 44 BRCA1 and 52 BRCA2 mutation-positive families. Using receiver operator characteristics analyses, the C-statistics were found to be 0.81, 0.80, 0.79, and 0.74 for the BRCAPRO, FHAT, Manchester, and Myriad II models, respectively, when incorporating both BRCA1 and BRCA2 mutation carrier predictions. For the BRCAPRO model, 75% scored greater than a 0.43 probability in the mutation-positive group and 75% scored less than 0.50 in the mutation-negative group. Only 38 of 128 (30%) mutation-negative group had a probability greater than 0.43 with the BRCAPRO model. While all models were highly predictive of carrier status, the BRCAPRO model was the most accurate where a cut-off of 10% would have eliminated 60 of 128 (47%) mutation-negative families for genetic testing and only miss 10 of 96 (10%) mutation-positive families. A review of the cancer phenotypes with high BRCAPRO probabilities showed that significantly more metachronous bilateral breast cancer cases occurred in BRCA1/2 mutation carrier families in comparison to mutation-negative families, a feature which is not discriminated in the BRCAPRO model.     

Genetic testing for BRCA1 and BRCA2 in the Province of Ontario

In 2001, genetic testing for BRCA1 and BRCA2 was introduced in Ontario, for women at high‐risk of breast or ovarian cancer. To date over 30,000 individuals have been tested throughout Ontario. Testing was offered to all Ontario residents who were eligible under any of 13 criteria. We report the results of tests conducted at Mount Sinai Hospital from 2007 to 2014. A total of 4726 individuals were tested, 764 (16.2%) were found to carry a pathogenic variant (mutation). Among 3684 women and men who underwent testing without a known familial BRCA mutation, 331 (9.0%) were found to carry a mutation. Among 1042 women and men tested for a known family mutation, 433 (41.6%) were positive. There were 603 female mutation carriers, of these, 303 were affected with breast or ovarian cancer (50%) and 16 with another cancer (2.3%). Of 284 unaffected female carriers, 242 (85%) were tested for a known family mutation and 42 (15%) were the first person in the family to be tested. By placing greater emphasis on recruiting unaffected female relatives of known mutation carriers for testing, greater than one‐half of newly identified carriers will be unaffected.     

Treatment‐focused DNA testing for newly diagnosed breast cancer patients: some implications for clinical practice

Lobb EA, Barlow‐Stewart K, Suthers G, Hallowell N. Treatment‐focused DNA testing for newly diagnosed breast cancer patients: some implications for clinical practice There is accumulating evidence that women with breast cancer due to a familial BRCA1 or BRCA2 mutation benefit from specific surgical and chemotherapeutic treatment strategies. However, the rapid identification of such patients during the acute phase of treatment raises a number of issues. This study investigated Australian opinion leaders' views on the issues arising from such ‘treatment‐focused’ genetic testing. Semi‐structured interviews with 34 opinion leaders working in cancer genetics were undertaken. Interviewees acknowledged the introduction of treatment‐focused DNA testing has the potential to positively transform the management of breast cancer patients, but were concerned that certain ethical and logistical issues have yet to be addressed. These include decision‐making and consent, the familial nature of genetic information, and the management of genetics services within familial cancer clinics in the public hospital system in Australia. Service providers will need to have policies and strategies for managing the increased demand. It will also be necessary to include genetic counseling services within familial cancer clinics in the care pathway for newly diagnosed patients prior to any DNA testing to determine adjuvant treatment; such services may be more cost‐effective than expecting surgeons and medical oncologists to fulfill this role.     

Familial breast cancer

Since the localization and discovery of the first high-risk breast cancer (BC) genes in 1990, there has been a substantial progress in unravelling its familial component. Increasing numbers of women at risk of BC are coming forward requesting advice on their risk and what they can do about it. Three groups of genetic predisposition alleles have so far been identified with high-risk genes conferring 40-85% lifetime risk including BRCA1, BRCA2 and TP53. Moderate risk genes (20-40% risk) including PALB1, BRIP, ATM and CHEK2, and a host of low-risk common alleles identified largely through genome-wide association studies. Currently, only BRCA1, BRCA2 and TP53 are used in clinical practice on a wide scale, although testing of up to 50-100 gene loci may be possible in the future utilizing next-generation technology.     

Prevalence of founder BRCA1 and BRCA2 mutations in unselected French Canadian women with breast cancer

The frequency of BRCA1 and BRCA2 mutations in women with breast cancer varies according to the age at diagnosis, family history of cancer, and ethnicity/country of origin. We set out to estimate the frequency of seven previously described founder mutations in BRCA1 and BRCA2 in all eligible French Canadian women diagnosed with invasive breast cancer at one Montreal hospital over a 20-month period. One hundred and ninety-two patients were eligible and 127 (66.2%) provided blood for genetic testing. We identified 4 women who carried a founder mutation (3.1%, 95% confidence interval 0.9-7.9%) in this population. Interestingly, all the mutations were in BRCA2. The mean age at diagnosis for mutation carriers was 51.2 years (range 49.1-53.5). Two of these 4 cases were lobular invasive carcinomas and 2 were ductal carcinomas, histological grade 1 or 2. Despite a small tumor size (< or =20 mm), axillary nodal involvement was present in 3 women. Estrogen receptors were strongly expressed in all cases. Two of the 4 cases reported a strong family history of breast cancer, but a family history of site-specific breast cancer was a relatively poor indicator of the presence of BRCA2 mutations. The absence of BRCA1 mutations may be a result of chance, but may also reflect different geographical origins of the most common BRCA1 mutations within the French Canadian population.     

Mutation Screening of the BRCA1 Gene in Early Onset and Familial Breast/Ovarian Cancer in Moroccan Population

Worldwide variation in the distribution of BRCA mutations is well recognised, and for the Moroccan population no comprehensive studies about BRCA mutation spectra or frequencies have been published. We therefore performed mutation analysis of the BRCA1 gene in 121 Moroccan women diagnosed with breast cancer. All cases completed epidemiology and family history questionnaires and provided a DNA sample for BRCA testing. Mutation analysis was performed by direct DNA sequencing of all coding exons and flanking intron sequences of the BRCA1 gene. 31.6 % (6/19) of familial cases and 1 % (1/102) of early-onset sporadic (< 45 years) were found to be associated with BRCA1 mutations. The pathogenic mutations included two frame-shift mutations (c.798_799delTT, c.1016dupA), one missense mutation (c.5095C>T), and one nonsense mutation (c.4942A>T). The c.798_799delTT mutation was also observed in Algerian and Tunisian BC families, suggesting the first non-Jewish founder mutation to be described in Northern Africa. In addition, ten different unclassified variants were detected in BRCA1, none of which were predicted to affect splicing. Most unclassified variants were placed in Align-GVGD classes suggesting neutrality. c.5117G>C involves a highly conserved amino acid suggestive of interfering with function (Align-GVGD class C55), but has been observed in conjunction with a deleterious mutation in a Tunisian family. These findings reflect the genetic heterogeneity of the Moroccan population and are relevant to genetic counselling and clinical management. The role of BRCA2 in BC is also under study.     

中国上海家族性乳腺癌BRCA1和BRCA2基因的突变

目的研究上海地区家族性乳腺癌中BRCA1／BRCA2基因的突变位点及携带情况。方法研究对象来自35个汉族家族性乳腺癌家系，家系中至少有一个一级亲属乳腺癌患病史。共35例患者，其中13例发病年龄≤加岁。由静脉血提取基因组DNA，对BRCA1／BRCA2基因的全部编码序列进行扩增。扩增产物突变分析先由变性高效液相色谱分析进行筛查，之后进行DNA直接测序证实。结果在BRCA1基因中发现有4个突变位点，其中2个为新发现位点——拼接点突变（IVS17-1G〉T；IVS21＋1G〉C）；另两个为已报道的致病突变位点——移码突变（1100delAT；5640delA）。BRCA2基因的1个致病突变位点位于11号外显子上，为移码突变（5802delAATT）。另外，共发现有12个新的单核苷重复多态位点，都未引起氨基酸编码改变；其中，8个在BRCA1基因上，4个在BRCA2基因上。在家族性乳腺癌中，BRCA1突变频率（11．4％）高于BRCA2基因（2．9％）。结论新发现的2个BRCA1基因的拼接点突变可能是中国上海人群家族性乳腺癌的特有突变位点；在我国上海地区人群中，BRCA1基因突变起着比BRCA2基因更大的作用；该研究丰富了中国人群中BRCA基因的突变谱，并为未来的临床基因检测提供了筛查模式。     

Presymptomatic testing for BRCA1 and BRCA2: how distressing are the pre-test weeks?

Presymptomatic DNA testing for autosomal dominant hereditary breast/ovarian cancer (HBOC) became an option after the identification of the BRCA1 and BRCA2 genes in 1994-1995. Healthy female mutation carriers have a high lifetime risk for breast cancer (56-87%) or ovarian cancer (10-60%) and may opt for intensive breast and ovary surveillance or prophylactic surgery (mastectomy/oophorectomy).We studied general and cancer related distress in 85 healthy women with a 25% or 50% risk of being carrier of a BRCA1/BRCA2 gene mutation and 66 partners in the six to eight week period between genetic counselling/blood sampling and disclosure of the test result. Questionnaire and interview data are analysed. Associations are explored between levels of distress and (1) expected consequences of being identified as a mutation carrier, (2) personality traits, (3) sociodemographic variables, and (4) experiences related to HBOC.Mean pre-test anxiety and depression levels in women at risk of being a carrier and partners were similar to those of a normal Dutch population. In about 25% of those at risk of being a carrier and 10% of the partners, increased to high levels of general and cancer related distress were found. Increased levels of distress were reported by women who (1) anticipated an increase in problems after an unfavourable test outcome, (2) considered prophylactic mastectomy if found to be mutation carrier, (3) had an unoptimistic personality, (4) tended to suppress their emotions, (5) were younger than 40 years, and (6) were more familiar with the serious consequences of HBOC. Recently obtained awareness of the genetic nature of cancer in the family was not predictive of distress.The majority of the women and their partners experienced a relatively calm period before the disclosure of the test result and seemed to postpone distressing thoughts until the week of disclosure of the result. The low distress levels may partly be explained by the use of strategies to minimise the emotional impact of a possibly unfavourable test outcome. However, a minority reported feeling very distressed. Several factors were found to be predictive for increased distress levels.     

The contribution of founder mutations to early-onset breast cancer in French-Canadian women

In an ethnically‐homogeneous population, it is valuable to identify founder mutations in cancer‐predisposing genes. Founder mutations have been found in four breast‐cancer‐predisposing genes in French‐Canadian breast cancer families. The frequencies of the mutant alleles have been measured neither in a large series of unselected breast cancer patients from Quebec, nor in healthy controls. These estimates are necessary to measure their contribution to the hereditary burden of breast cancer in Quebec and to help develop genetic screening policies which are appropriate for the province. We studied 564 French‐Canadian women with early‐onset invasive breast cancer who were treated at a single Montreal hospital. Patients had been diagnosed at age 50 or less, and were ascertained between 2004 and 2008. We screened all 564 patients for nine founder mutations: four in BRCA1, three in BRCA2 and one each in PALB2 and CHEK2. We also studied 6433 DNA samples from newborn infants from the Quebec City area to estimate the frequency of the nine variant alleles in the French‐Canadian population. We identified a mutation in 36 of the 564 breast cancer cases (6.4%) and in 35 of 6443 controls (0.5%). In the breast cancer patients, the majority of mutations were in BRCA2 (54%). However, in the general population (newborn infants), the majority of mutations were in CHEK2 (54%). The odds ratio for breast cancer to age 50, given a BRCA1 mutation, was 10.1 (95% CI: 3.7–28) and given a BRCA2 mutation was 29.5 (95% CI: 12.9–67). The odds ratio for breast cancer to age 50, given a CHEK2 mutation, was 3.6 (95% CI: 1.4–9.1). One‐half of the women with a mutation had a first‐ or second‐degree relative diagnosed with breast or ovarian cancer. Thus, it can be concluded that a predisposing mutation in BRCA1, BRCA2, CHEK2 or PALB2 is present in approximately 6% of French‐Canadian women with early‐onset breast cancer. It is reasonable to offer screening for founder mutations to all French‐Canadian women with breast cancer before age 50. The frequency of these mutations in the general population (0.5%) is too low to advocate population‐based screening.     

Family history as a predictor of uptake of cancer preventive procedures by women with a BRCA1 or BRCA2 mutation

Women with a BRCA1 or BRCA2 mutation are at an elevated risk of developing breast and ovarian cancer; however, it is unclear to what extent family history influences the uptake of cancer prevention options.Women with a BRCA1/2 mutation completed a follow-up questionnaire that assessed uptake of cancer preventive options. The pedigree of each woman was reviewed, and information was recorded on cancers diagnosed in relatives. Five hundred and seventeen women were included in the study. Women with a sister with breast cancer were more likely to have a prophylactic mastectomy than those without a sister with breast cancer [odds ratios (OR) = 2.4, p = 0.003]. Uptake of prophylactic mastectomy was significantly lower in women with a mother with ovarian cancer compared with those whose mother did not have ovarian cancer (OR = 0.4, p = 0.01). Having a mother or sister with ovarian cancer significantly predicted the uptake of prophylactic oophorectomy (OR = 1.6, p = 0.04). Women with a BRCA2 mutation were less likely to have a prophylactic oophorectomy than those with a BRCA1 mutation (OR = 0.49, p = 0.0004). Among women with a BRCA1 or BRCA2 mutation, family history predicts the uptake of prophylactic mastectomy and prophylactic oophorectomy.     

Contribution of the BRCA1 and BRCA2 mutations to breast cancer in Tunisia

Hereditary breast cancer accounts for 3–8% of all breast cancers, with mutations in the BRCA1 and BRCA2 genes responsible for up to 30% of these. To investigate the prevalence of BRCA1 and BRCA2 gene mutations in breast cancer patients with affected relatives in Tunisia, we studied 36 patients who had at least one first degree relative with breast and/or ovarian cancer Thirty-four 34 patients were suggestive of the BRCA1 mutation and two were suggestive of the BRCA2 mutation, based on the presence of male breast cancer detected in their corresponding pedigrees. Four mutations in BRCA1 were detected, including a novel frame-shift mutation (c.211dupA) in two unrelated patients and three other frameshift mutations – c.4041delAG, c.2551delG and c.5266dupC. Our study is the first to describe the c.5266dupC mutation in a non-Jewish Ashkenazi population. Two frameshift mutations (c.1309del4 and c.5682insA) were observed in BRCA2. Nineteen percent (7/36) of the familial cases had deleterious mutations of the BRCA1 or BRCA2 genes. Almost all patients with deleterious mutations of BRCA1 reported a family history of breast and/or ovarian cancer in the index case or in their relatives. Our data are the first to contribute to information on the mutation spectrum of BRCA genes in Tunisia, and we give a recommendation for improving clinical genetic testing policy.     

BRCA1/2 testing: uptake, phenocopies, and strategies to improve detection rates in initially negative families

Fischer C, Engel C, Sutter C, Zachariae S, Schmutzler R, Meindl A, Heidemann S, Grimm T, Goecke TO, Debatin I, Horn D, Wieacker P, Gadzicki D, Becker K, Schäfer D, Stock F, Voigtländer T, on behalf of the German Consortium for Hereditary Breast and Ovarian Cancer. BRCA1/2 testing: uptake, phenocopies, and strategies to improve detection rates in initially negative families. In families with clustering of breast and ovarian cancer, molecular testing of the major susceptibility genes BRCA1/2 helps to identify patients with disease mutations and healthy persons at high risk who can participate in targeted intervention programs. We investigated 5559 families from the German Consortium for Hereditary Breast and Ovarian Cancer included between 1997 and 2008 and treated under clinical routine conditions. In each family an index patient/person had been screened for deleterious mutations in BRCA1/2. Healthy relatives agreed to predictive testing in 888 of 1520 BRCA1/2 mutation‐positive families (58%). Of 2646 eligible unaffected first‐degree relatives 1143 decided to be tested (43%). In 325 families with BRCA1/2‐positive index patients one related BC/OC patient was tested and 39 (12.0%; 95% confidence interval: 8.7–16.0%) discrepant cases found. A second related individual was screened in 163 of 3388 (4.9%) families with BRCA1/2‐negative index patient and in eight families a BRCA1/2 mutation was found. In BRCA1/2 mutation‐positive families, BC/OC patients lacking the familial mutation have to be expected at a rather high rate. In families with BRCA1/2‐negative index patient we recommend a second screening if another patient with a high probability of carrying a BRCA1/2 mutation is available.     

BRCA1 and BRCA2 mutation analysis in breast-ovarian cancer families from northeastern Poland

Sixty high-risk breast and/or ovarian cancer families from North-Eastern Poland were screened for germline mutations in BRCA1 (MIM# 113705) and BRCA2 (MIM# 600185), using a combination of protein truncation test, denaturing high-performance liquid chromatography and direct sequencing. Sixteen (27%) of the families were found to carry nine different BRCA mutations, including 14 families with BRCA1 mutation and two families with BRCA2 mutation. The results suggest the presence of two strong BRCA1 founder mutations in the Polish population - 5382insC (6 families) and 300T>G (Cys61Gly; 3 families). The remaining seven mutations were found in single families and included three previously reported BRCA1 mutations (185delAG, 2682C>T [Gln855Ter] and 3819del5), a novel BRCA1 mutation (IVS14+1G>A), as well as two BRCA2 mutations (4088delA and 7985G>A [Trp2586Ter]) not previously observed in Polish families. We confirm the strong influence of two Central-Eastern European BRCA1 founder mutations in familial breast and/or ovarian cancer in Poland. We also conclude that the Polish population has a more dispersed BRCA mutation spectrum than had been earlier thought. This warrants further careful BRCA mutation screening in order to optimise genetic counselling and disease prevention in affected families.     

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.