Activation of anti-oxidant Nrf2 signaling by enone analogues of curcumin.

Inflammation and oxidative stress are common in many chronic diseases. Targeting signaling pathways that contribute to these conditions may have therapeutic potential. The transcription factor Nrf2 is a major regulator of phase II detoxification and anti-oxidant genes as well as anti-inflammatory and neuroprotective genes. Nrf2 is widespread in the CNS and is recognized as an important regulator of brain inflammation. The natural product curcumin exhibits numerous biological activities including ability to induce the expression of Nrf2-dependent phase II and anti-oxidant enzymes. Curcumin has been examined in a number of clinical studies with limited success, mainly owing to limited bioavailability and rapid metabolism. Enone analogues of curcumin were examined with an Nrf2 reporter assay to identify Nrf2 activators. Analogues were separated into groups with a 7-carbon dienone spacer, as found in curcumin; a 5-carbon enone spacer with and without a ring; and a 3-carbon enone spacer. Activators of Nrf2 were found in all three groups, many of which were more active than curcumin. Dose-response studies demonstrated that a range of substituents on the aromatic rings of these enones influenced not only the sensitivity to activation, reflected in EC50 values, but also the extent of activation, which suggests that multiple mechanisms are involved in the activation of Nrf2 by these analogues.

A high frequency of PALB2 mutations in Jamaican patients with breast cancer.

PURPOSE: Jamaica is an island nation with one of the highest breast cancer incidence rates in the Caribbean (40/100,000 per year). The contribution of cancer susceptibility gene mutations to the burden of breast cancer in Jamaica has not yet been explored. We sought to determine the prevalence of germline mutations in BRCA1, BRCA2, and PALB2 in 179 unselected Jamaican women with breast cancer. METHODS: We sequenced the entire coding regions of BRCA1, BRCA2, and PALB2 for all the study subjects. RESULTS: Overall, 8 of 179 patients (4.5%) had a mutation in one of the three genes: one in BRCA1, two in BRCA2, and five in PALB2. CONCLUSIONS: These data suggest that in addition to BRCA1 and BRCA2, PALB2 should be included in genetic testing for breast cancer patients in Jamaica.

Activation of anti-oxidant Nrf2 signaling by substituted trans stilbenes.

Nrf2, which is a member of the cap'n'collar family of transcription factors, is a major regulator of phase II detoxification and anti-oxidant genes as well as anti-inflammatory and neuroprotective genes. The importance of inflammation and oxidative stress in many chronic diseases supports the concept that activation of anti-oxidant Nrf2 signaling may have therapeutic potential. A number of Nrf2 activators have entered into clinical trials. Nrf2 exists in the cytosol in complex with its binding partner Keap1, which is a thiol-rich redox-sensing protein. In response to oxidative and electrophilic stress, select cysteine residues of Keap1 are modified, which locks Keap1 in the Nrf2-Keap1 complex and allows newly synthesized Nrf2 to enter the nucleus. Numerous Nrf2-activating chemicals, including a number of natural products, are electrophiles that modify Keap1, often by Michael addition, leading to activation of Nrf2. One concern with the design of Nrf2 activators that are electrophilic covalent modifiers of Keap1 is the issue of selectivity. In the present study, substituted trans stilbenes were identified as activators of Nrf2. These activators of Nrf2 are not highly electrophilic and therefore are unlikely to activate Nrf2 through covalent modification of Keap1. Dose-response studies demonstrated that a range of substituents on either ring of the trans stilbenes, especially fluorine and methoxy substituents, influenced not only the sensitivity to activation, reflected in EC50 values, but also the extent of activation, which suggests that multiple mechanisms are involved in the activation of Nrf2. The stilbene backbone appears to be a privileged scaffold for development of a new class of Nrf2 activators.

Revisiting breast cancer patients who previously tested negative for BRCA mutations using a 12-gene panel.

PURPOSE: BRCA mutations contribute to about 20% of all hereditary breast cancers. With full-genome sequencing as the emerging standard for genetic testing, other breast cancer susceptibility genes have been identified and may collectively contribute to up to 30% of all hereditary breast cancers. We re-assessed women who had previously tested negative for a BRCA mutation when outdated techniques were used, and discuss the implications of identifying a mutation several years after initial genetic testing. METHODS: We evaluated the prevalence of mutations in 12 breast cancer susceptibility genes (including BRCA1 and BRCA2) in 190 breast cancer patients with a strong family history of breast cancer. These women had previously tested negative for mutations in the large coding exons of BRCA1 and BRCA2 using the protein truncation test (PTT) between the years of 1996 and 2013. RESULTS: We identified pathogenic mutations in 17 of 190 (9%) women. Six mutations were detected in BRCA1 (n = 2) and BRCA2 (n = 4). Eleven mutations were found in other breast cancer susceptibility genes including CHEK2 (n = 5), PALB2 (n = 2), BLM (n = 2), ATM (n = 1) and TP53 (n = 1). CONCLUSION: Among 190 breast cancer patients with a family history of the disease, and who previously received a negative result for BRCA mutations using the PTT, 17 (9%) women were found to carry a high-risk pathogenic mutation in a breast cancer susceptibility gene. Six of these women were BRCA mutation carriers who were missed previously. These findings support the rationale for updated genetic testing in patients who tested BRCA mutation negative using outdated techniques.

A Survey of BRCA1, BRCA2, and PALB2 mutations in women with breast cancer in Trinidad and Tobago.

The mortality rate from breast cancer in the nation of Trinidad and Tobago is among the highest of any country in the Caribbean region. The contribution of inherited gene mutations to the burden of breast cancer in Trinidad and Tobago has not been studied. We examined the prevalence of mutations in three susceptibility genes (BRCA1, BRCA2, and PALB2) in breast cancer patients in Trinidad and Tobago. We studied 268 unselected breast cancer patients from Trinidad and Tobago and looked for mutations across the entire coding sequences of BRCA1, BRCA2, and PALB2. Overall, 28 of 268 patients (10.4 %) had a mutation in one of the three genes, including 15 in BRCA1, ten in BRCA2, two in PALB2, and one in both BRCA2 and PALB2. There were 25 different mutations identified; of these, four mutations were seen in two patients each. Given the high prevalence of mutations, it is reasonable to offer genetic testing for these three genes to all breast cancer patients in Trinidad and Tobago.

Profiling Fanconi Anemia Gene Mutations among Iranian Patients.

BACKGROUND: Fanconi anemia (FA) is a rare genetic syndrome characterized by developmental defects, bone marrow failure, and a high cancer risk. FA is usually inherited as an autosomal recessive condition. This disease is genetically heterogeneous and mutations in 16 different genes have been identified in FA patients to date. An accurate diagnosis needs detection of pathogenic variations in the FA genes along with positive results from chromosome breakage test. METHODS: In this study, 48 families with at least 2 affected FA patients and positive chromosome breakage test were enrolled from the Iranian population. Molecular analysis of FA genes was performed using Next Generation Sequencing (NGS) method and Multiple Ligation Dependent Probe Amplification (MLPA). RESULTS: Causal mutations for 30 (63%) patients were identified in homozygous or compound heterozygous forms. FANCA had the highest mutation frequency rate (83%) followed by FANCG (10%), FANCD2 (3%) and FANCL (3%). A significant proportion (44%) of FANCA mutations were large rearrangements. CONCLUSION: Genetic testing for FA patients improves the accuracy of diagnosis and also will be essential for genetic counselling and prenatal diagnosis for future pregnancies in the family. Availability of NGS technology has made the screening of all known FA genes at once more practical and affordable.

Recurrent BRCA1 and BRCA2 mutations in Mexican women with breast cancer.

BACKGROUND: Germline mutations in the BRCA1 and BRCA2 genes confer an estimated 58% to 80% lifetime risk of breast cancer. In general, screening is done for cancer patients if a relative has been diagnosed with breast or ovarian cancer. There are few data on the prevalence of mutations in these genes in Mexican women with breast cancer and this hampers efforts to develop screening policies in Mexico. METHODS: We screened 810 unselected women with breast cancer from three cities in Mexico (Mexico City, Veracruz, and Monterrey) for mutations in BRCA1 and BRCA2, including a panel of 26 previously reported mutations. RESULTS: Thirty-five mutations were identified in 34 women (4.3% of total) including 20 BRCA1 mutations and 15 BRCA2 mutations. Twenty-two of the 35 mutations were recurrent mutations (62.8%). Only five of the 34 mutation carriers had a first-degree relative with breast cancer (three with BRCA1 and two with BRCA2 mutations). CONCLUSION: These results support the rationale for a strategy of screening for recurrent mutations in all women with breast cancer in Mexico, as opposed to restricting screening to those with a sister or mother with breast or ovarian cancer. IMPACT: These results will impact cancer genetic testing in Mexico and the identification of at-risk individuals who will benefit from increased surveillance. Cancer Epidemiol Biomarkers Prev; 24(3); 498-505. ©2014 AACR.

Prevalence of BRCA1 and BRCA2 mutations in unselected breast cancer patients from medellín, Colombia.

BACKGROUND: Approximately 5% of all breast cancers can be attributed to a mutation in the BRCA1 or BRCA2 gene. The genetic component of breast cancer in Colombia has been, for the most part, studied on cases from the Bogota region. Five different founder mutations were in two studies of breast cancer patients in the Bogota region. It is important that the frequency of mutations be established among unselected cases of breast cancer of other regions of Colombia in order to estimate the genetic burden of this cancer in Colombia and to plan genetic services. The aim of this study was to establish the mutation frequencies of the BRCA genes in breast cancer patients unselected for family history or age, from Medellin, Colombia. METHODS: We enrolled 280 unselected women with breast cancer from a large public hospital in Medellin, Colombia. A detailed family history from each patient and a blood sample was obtained and processed for DNA analysis. Mutations in BRCA1 and BRCA2 were sought using a combination of techniques including a panel of recurrent Hispanic BRCA mutations which consists of fifty BRCA1 mutations and forty-six BRCA2 mutations, including the five recurrent Colombian BRCA mutations. All mutations were confirmed by direct sequencing. RESULTS: Genetic testing was successfully completed for 244 of the 280 cases (87%). Among the 244 cases, three deleterious mutations were identified (two in BRCA1 and one in BRCA2) representing 1.2% of the total. The average age of breast cancer in the mutation-positive cases was 34 years. The two BRCA1 mutations were known founder mutations (3450del4 in exon 11 and A1708E in exon 18). The BRCA2 mutation was in exon 11 (5844del5) and has not been previously reported in individuals of Colombian descent. Among the three mutation-positive families was a breast cancer family and two families with no history of breast or ovarian cancer. CONCLUSION: The frequency of BRCA mutations in unselected breast cancer cases from the Medellin region of Colombia is low and is approximately 1.2%.

Early onset breast cancer in a registry-based sample of African-american women: BRCA mutation prevalence, and other personal and system-level clinical characteristics.

Young Black women are disproportionately afflicted with breast cancer, a proportion of which may be due to BRCA1 and BRCA2 (BRCA) gene mutations. In a sample of Black women with early onset breast cancer, we evaluated BRCA mutations and explored personal and system-level clinical characteristics. Black women diagnosed with invasive breast cancer (age ≤50) were recruited through the state cancer registry. Participants completed a questionnaire, genetic counseling and BRCA testing. Of the 48 women who consented to study participation, 46 provided a usable biologic specimen for BRCA testing. The overall prevalence of BRCA mutations and variants of uncertain significance (VUS) in participants was 6.5% and 34.8%, respectively. Of these, only 14 were referred for genetic counseling prior to study enrollment. Overall, those participants who chose to undergo bilateral mastectomy had a higher number of relatives with breast and ovarian cancer (p = 0.024) and a higher household income (p = 0.009). BRCA mutation prevalence and the high prevalence of VUS in participants are consistent with prior studies. Furthermore, clinical factors such as family history and financial means may influence type of surgery recommended and chosen, at both the provider and patient level, respectively. Finally, the limited number of patients referred for genetic counseling prior to surgical treatment for breast cancer may represent a missed clinical opportunity to inform surgical decisions.

The HOXB13 p.Gly84Glu mutation is not associated with the risk of breast cancer.

Recently, the HOXB13 gene has been shown to be a susceptibility gene for prostate cancer. HOXB13 is overexpressed in breast cancer tissues and HOXB13 expression in combination with low expression of IL17BR is predictive for a tamoxifen response in ER-positive breast cancers. Based on observations, we hypothesized that the HOXB13 p.Gly84Glu mutation might be associated with breast cancer risk. We genotyped this mutation in the germline DNA of 4,037 women with breast cancer (including 1,082 familial cases) and in 2,762 controls from Canada and Poland. Seven heterozygous carriers of the HOXB13 p.Gly84Glu mutation were found in the cases (0.17 %) compared to four carriers among the controls (0.14 %; OR = 1.2, 95 % CI = 0.34-4.1, p = 1.0). Only one of the seven carriers had a family history of breast cancer. This study does not support the hypothesis that women who carry the HOXB13 Gly84Glu mutation are at increased risk of breast cancer.

A chemical analog of curcumin as an improved inhibitor of amyloid Abeta oligomerization.

Amyloid-like plaques are characteristic lesions defining the neuropathology of Alzheimer's disease (AD). The size and density of these plaques are closely associated with cognitive decline. To combat this disease, the few therapies that are available rely on drugs that increase neurotransmission; however, this approach has had limited success as it has simply slowed an imminent decline and failed to target the root cause of AD. Amyloid-like deposits result from aggregation of the Aß peptide, and thus, reducing amyloid burden by preventing Aß aggregation represents an attractive approach to improve the therapeutic arsenal for AD. Recent studies have shown that the natural product curcumin is capable of crossing the blood-brain barrier in the CNS in sufficient quantities so as to reduce amyloid plaque burden. Based upon this bioactivity, we hypothesized that curcumin presents molecular features that make it an excellent lead compound for the development of more effective inhibitors of Aß aggregation. To explore this hypothesis, we screened a library of curcumin analogs and identified structural features that contribute to the anti-oligomerization activity of curcumin and its analogs. First, at least one enone group in the spacer between aryl rings is necessary for measureable anti-Aß aggregation activity. Second, an unsaturated carbon spacer between aryl rings is essential for inhibitory activity, as none of the saturated carbon spacers showed any margin of improvement over that of native curcumin. Third, methoxyl and hydroxyl substitutions in the meta- and para-positions on the aryl rings appear necessary for some measure of improved inhibitory activity. The best lead inhibitors have either their meta- and para-substituted methoxyl and hydroxyl groups reversed from that of curcumin or methoxyl or hydroxyl groups placed in both positions. The simple substitution of the para-hydroxy group on curcumin with a methoxy substitution improved inhibitor function by 6-7-fold over that measured for curcumin.

The R337H mutation in TP53 and breast cancer in Brazil.

BACKGROUND: Germline mutations in p53 are associated with the Li-Fraumeni Syndrome which is characterized by childhood cancers, including pediatric adrenal cortical carcinomas and early onset breast cancer. The high incidence of adrenal cortical carcinomas in southern Brazil is mostly attributed to the R337H mutation in TP53. The relatively high population frequency of this mutation in southern Brazil, along with the clustering of early onset breast cancer in Li-Frameni families, suggests this mutation may also be a low-penetrance breast cancer susceptibility polymorphism. METHODS: We undertook this study to evaluate the frequency of the R337H mutation in breast cancer patients from Rio de Janeiro, Brazil. R337H mutation status was determined in 390 unselected breast cases and 324 controls identified from clinics in Rio de Janeiro, Brazil using a PCR-based assay. RESULTS: Two of the breast cancer cases (0.5%) and none of the controls carried the mutation. Both cases had an early age at diagnosis (< 40 years old) and a family history of breast and other cancers. CONCLUSIONS: These data suggest genetic screening of young onset breast cancer patients should include testing for the R337H mutation.

The BRCA2 c.9004G>A (E2002K) [corrected] variant is likely pathogenic and recurs in breast and/or ovarian cancer families of French Canadian descent.

Specific BRCA1 and BRCA2 mutations recur in French Canadian breast and/or ovarian cancer families because of common ancestors, facilitating carrier detection in this population. We recently reported a BRCA2 c.9004G>A variant of unknown clinical significance in two French Canadian breast cancer families. It confers a E3002K alteration in the conserved C-terminus domain of BRCA2, and has been reported in non-French Canadian cancer families. Seven variant positive French Canadian families have since been identified by mutation screening of referrals to hereditary cancer clinics. In this article, we describe the cancer phenotypes of these families and further assess the contribution of this variant in the French Canadian population. We screened index breast cancer cases from 58 cancer families with at least three confirmed cases of breast and/or ovarian cancer and 960 breast cancer cases (48 years mean age) not selected for family history of cancer that were previously found not to carry the most common BRCA1 and BRCA2 mutations reported in this population. The index variant-positive cases from each family had breast cancer between the ages of 35-55 years (43 years mean age); and reported close relatives with breast cancer diagnoses between the ages of 28-84 years (57 years mean age). Three families had ovarian or peritoneal cancers. BRCA2-associated cancers, such as bladder, esophagus, pancreas, prostate, and thyroid cancers also occurred in these families. One c.9004G>A carrier also harbored the PALB2 c.2323C>T (Q775X) mutation found to recur in French Canadian breast cancer cases. No new BRCA2 variant carriers were identified in mutation screens. The absence of BRCA2 c.9004G>A carriers in the breast cancer cases not selected for family history contrasts with familial cases, supporting a pathogenic status for this variant and addition to the existing common BRCA1 and BRCA2 mutation-screening panel for French Canadian breast and/or ovarian cancer families.

BRCA1 and BRCA2 mutations among ovarian cancer patients from Colombia.

OBJECTIVE: The contribution of BRCA1 and BRCA2 mutations to ovarian cancer in Colombia has not yet been explored. Five founder mutations have been identified in two previous studies of breast cancer patients in the Bogota region [1,2]. It is important that the frequency of mutations be established among unselected cases of ovarian cancer in order to estimate the genetic burden of this cancer in Colombia and to plan genetic and preventive services. METHODS: We enrolled 100 unselected women with ovarian cancer from the Bogota region, and from northern and southern central regions of Colombia. A detailed family history was obtained from each patient and a blood sample was processed for DNA analysis. DNA quality was adequate for BRCA testing for 96 women. Mutations in BRCA1 and BRCA2 were sought using a Hispanic BRCA mutation testing panel. All mutations were confirmed by direct sequencing. RESULTS: Fifteen mutations were identified (two in BRCA2 and thirteen in BRCA1) representing 15.6% of the total (95% CI: 7.8% to 21.3%). Among the 15 mutation-positive families there were nine breast-ovarian cancer families, one gastric cancer family, one prostate cancer family, three uterine cancer families, and one family with no history of cancer. A single founder mutation in BRCA1 (3450del4) was seen in 11 patients. CONCLUSION: In summary, BRCA1 founder mutations are common in Colombian women with ovarian cancer. Approximately 11.5% of all ovarian cancer cases in the Bogota region are attributable to a single BRCA1 founder mutation.

Synthesis of benzyl substituted naphthalenes from benzylidene tetralones.

A convenient and efficient synthesis of novel highly substituted dimethoxybenzylnaphthalenes, which are precursors to several dihydroxynaphthoic acids, is described. The approach involves the use of aldol chemistry to provide a number of benzylidene tetralones, which are converted to the target naphthalenes in three steps, with good to excellent yields. Grignard reaction of intermediate benzyl tetralones provided 1-substituted benzyl naphthalenes. The reported synthesis is flexible and scalable and provides access to naphthalenes having a variety of substitution patterns. These benzyl substituted naphthalenes are being converted to naphthoic acids and the bioactivities of these compounds are currently being investigated.

Prevalence of BRCA1 and BRCA2 mutations in unselected breast cancer patients from Greece.

BACKGROUND: Inheritance of a mutation in either BRCA1 or BRCA2 accounts for approximately 5% of all breast cancer cases, but varies by country. Investigations into the contribution of BRCA mutations to breast cancer incidence in Greece have been, for the most part, limited by small sample sizes and by the use of cases selected for their family history of cancer. The aim of the current study was to estimate BRCA mutation frequencies in breast cancer patients unselected for family history. METHODS: To do so, we enrolled 127 unselected women with breast cancer from the Alexandra Hospital in Athens, Greece, a large public hospital in the city. Mutations in BRCA1 and BRCA2 were detected using a combination of techniques and were confirmed by direct sequencing. Two large genomic deletions were sought using mutation-specific assays. A detailed family history of cancer was obtained from each patient. RESULTS: We were able to successfully complete testing on samples from 127 women. Among these, six mutations were identified (four in BRCA1 and two in BRCA2) representing 4.7% of the total or 9.5% of cases diagnosed before age forty. None of the mutation carriers had a family history of breast or ovarian cancer. Three of the four BRCA1 mutations were in exon 20: two were a G5331A mutation and the third was a 3.2 kb deletion. The fourth BRCA1 mutation was the 3819delGTAAA in exon 11. The two BRCA2 mutations were in exon 11 (3782del10 and 4512insT). CONCLUSIONS: The G5331A mutation in BRCA1 appears to be a founder mutation in the Greek population.

Clinical impact of unclassified variants of the BRCA1 and BRCA2 genes.

Women who carry a pathogenic mutation in BRCA1 or BRCA2 have high risks of developing breast and ovarian cancers. The functional effect of many missense variants on BRCA1 and BRCA2 protein function is not known. Here, the authors construct a historical cohort of 4030 female first-degree relatives of 1345 unselected patients with ovarian cancer who have been screened for BRCA1 and BRCA2 mutations. The authors compared the risks by the age of 80 years for all cancers combined in female first-degree relatives of women with a pathogenic mutation, women with a variant of unknown significance (unclassified variant) and non-carriers. The cumulative risk of cancer among the relatives of patients with a pathogenic mutation was much higher than the risk in relatives of non-carriers (50.2% vs 28.5%; HR=2.87, p<10(-4)). In contrast, the cumulative risk of cancer among relatives of patients carrying an unclassified variant was similar to the risk of cancer for relatives of non-carriers (27.6% vs 28.5%; HR=1.08, p=0.79). The authors used three different algorithms to predict the pathogenicity of unclassified variants and compared their penetrance with non-carriers. In this sample, only Align Grantham Variation Grantham Deviation appeared to predict penetrance based on first-degree relatives.

Frequencies of BRCA1 and BRCA2 mutations among 1,342 unselected patients with invasive ovarian cancer.

BACKGROUND: The heritable fraction of ovarian cancer exceeds that of any other common adult cancer. Most inherited cases of ovarian cancer are due to a germline mutation in BRCA1 or BRCA2. It is important to have an accurate estimate of the proportion of ovarian cancer patients who carry a mutation and the specific factors which predict the presence of a mutation. METHODS: We tested a population-based series of 1342 unselected patients diagnosed with invasive ovarian cancer between 1995-1999 and 2002-2004 in Ontario, Canada, for germline mutations in BRCA1 and BRCA2. The two genes were tested in their entirety, using a range of techniques, including multiplex ligation-dependent probe amplification (MLPA). RESULTS: Among the 1342 women, 176 women carried a mutation (107 in BRCA1, 67 in BRCA2, and two in both genes) for a combined mutation frequency of 13.3%. Seven deletions were identified using MLPA (3.9% of all detected mutations). The prevalence of mutations was particularly high among women diagnosed in their forties (24.0%), in women with serous ovarian cancer (18.0%) and women of Italian (43.5%), Jewish (30.0%) or Indo-Pakistani origin (29.4%). A mutation was seen in 33.9% of women with a first-degree relative with breast or ovarian cancer and in 7.9% of women with no first-degree relative with breast or ovarian cancer. No mutation was seen in women with mucinous carcinoma. CONCLUSIONS: BRCA1 and BRCA2 mutations are common in women with invasive ovarian cancer. All women diagnosed with invasive non-mucinous ovarian cancer should be considered to be candidates for genetic testing.

A high prevalence of BRCA1 mutations among breast cancer patients from the Bahamas.

The Bahamas is a group of islands in the Caribbean with a high incidence of early onset breast cancer. In isolated populations, the identification of founder mutations in cancer predisposing genes may facilitate genetic testing and counseling. To date, six distinct BRCA1 mutations have been found in patients from cancer families from the Bahamas. The frequencies of these mutant alleles have not been measured in a large series of unselected breast cancer patients from Bahamas. We studied 214 Bahamian women with invasive breast cancer, unselected for age or family history of cancer. All patients were screened for six mutations in the BRCA1 gene that have previously been reported in cancer patients from the Bahamas. A mutation was identified in 49 of the 214 breast cancer patients (23%). The mutation frequency was particularly high in women diagnosed before age 50 (33%) in women with a first-degree relative with breast or ovarian cancer (41%) and in women with bilateral breast cancer (58%). Approximately 23% of unselected cases of breast cancer in the Bahamian population are attributable to a founder mutation in the BRCA1 gene-this is the highest reported mutation prevalence for any country studied to date. Genetic testing for these mutations is advisable for all women diagnosed with breast cancer in the Bahamas.

International distribution and age estimation of the Portuguese BRCA2 c.156_157insAlu founder mutation.

The c.156_157insAlu BRCA2 mutation has so far only been reported in hereditary breast/ovarian cancer (HBOC) families of Portuguese origin. Since this mutation is not detectable using the commonly used screening methodologies and must be specifically sought, we screened for this rearrangement in a total of 5,443 suspected HBOC families from several countries. Whereas the c.156_157insAlu BRCA2 mutation was detected in 11 of 149 suspected HBOC families from Portugal, representing 37.9% of all deleterious mutations, in other countries it was detected only in one proband living in France and in four individuals requesting predictive testing living in France and in the USA, all being Portuguese immigrants. After performing an extensive haplotype study in carrier families, we estimate that this founder mutation occurred 558 ± 215 years ago. We further demonstrate significant quantitative differences regarding the production of the BRCA2 full length RNA and the transcript lacking exon 3 in c.156_157insAlu BRCA2 mutation carriers and in controls. The cumulative incidence of breast cancer in carriers did not differ from that of other BRCA2 and BRCA1 pathogenic mutations. We recommend that all suspected HBOC families from Portugal or with Portuguese ancestry are specifically tested for this rearrangement.