Prevalence of BRCA1 and BRCA2 Jewish mutations in Spanish breast cancer patients

Mutations in BRCA-related breast and ovarian cancer in the South African Indian population: A descriptive study

Knowledge of the genetic landscape of a specific population group is vital for population-specific diagnosis and treatment of familial breast cancer. Although BRCA-related diagnostic testing has long been implemented in South Africa, the genotyping approach previously failed for the SA Indian population as it was based on other SA population groups. Because this population is uniquely admixed, the lack of population-specific data resulted in the implementation of comprehensive mutation screens for BRCA1/2. A total of 223 female patients were screened for clinically actionable variants. High-resolution melting analysis (HRMA) was used to screen 88 patients for DNA alterations in the coding and splice site boundaries of BRCA1 exons 2-9, BRCA1 exons 11-23, BRCA2 exons 2-9 and BRCA2 exons 12-27. The protein truncation test (PTT) was used to screen the three larger exons (BRCA1 exon 10 and BRCA2 exons 10 and 11) for protein termination changes. Multiplex ligation-dependent probe amplification (MLPA) was used to determine the presence of larger indels and possible copy number differences. Next Generation Sequencing (NGS) was performed on the remaining 135 samples. All potential variants were confirmed by performing Sanger DNA sequencing. The search revealed 28 different pathogenic heterozygotic variants, together with nine variants of unknown significance (VUS). The results suggested that the SA Indian population represents a different genetic admixture compared to that of mainland India, as only five pathogenic variants corresponded to those reported for mainland India. Familial breast cancer testing for SA Indian patients should therefore be performed as comprehensively as possible as the pathogenic variants seem to be family- rather than population-specific. Furthermore, predictive testing of family members will contribute to relieve the financial burden on the country's healthcare system, as increased surveillance and appropriate management could prevent disease.

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.

Dealing with the unexpected: consumer responses to direct-access BRCA mutation testing

Background. Inherited BRCA gene mutations convey a high risk for breast and ovarian cancer, but current guidelines limit BRCA mutation testing to women with early-onset cancer and relatives of mutation-positive cases. Benefits and risks of providing this information directly to consumers are unknown.

Methods. To assess and quantify emotional and behavioral reactions of consumers to their 23andMe Personal Genome Service^® report of three BRCA mutations that are common in Ashkenazi Jews, we invited all 136 BRCA1 and BRCA2 mutation-positive individuals in the 23andMe customer database who had chosen to view their BRCA reports to participate in this IRB-approved study. We also invited 160 mutation-negative customers who were matched for age, sex and ancestry. Semi-structured phone interviews were completed for 32 mutation carriers, 16 women and 16 men, and 31 non-carriers. Questions addressed personal and family history of cancer, decision and timing of viewing the BRCA report, recollection of the result, emotional responses, perception of personal cancer risk, information sharing, and actions taken or planned.

Results. Eleven women and 14 men had received the unexpected result that they are carriers of a BRCA1 185delAG or 5382insC, or BRCA2 6174delT mutation. None of them reported extreme anxiety and four experienced moderate anxiety that was transitory. Remarkably, five women and six men described their response as neutral. Most carrier women sought medical advice and four underwent risk-reducing procedures after confirmatory mutation testing. Male carriers realized that their test results implied genetic risk for female relatives, and several of them felt considerably burdened by this fact. Sharing mutation information with family members led to screening of at least 30 relatives and identification of 13 additional carriers. Non-carriers did not report inappropriate actions, such as foregoing cancer screening. All but one of the 32 mutation-positive participants appreciated learning their BRCA mutation status.

Conclusions. Direct access to BRCA mutation tests, considered a model for high-risk actionable genetic tests of proven clinical utility, provided clear benefits to participants. The unexpected information demonstrated a cascade effect as relatives of newly identified carriers also sought testing and more mutation carriers were identified. Given the absence of evidence for serious emotional distress or inappropriate actions in this subset of mutation-positive customers who agreed to be interviewed for this study, broader screening of Ashkenazi Jewish women for these three BRCA mutations should be considered.

Breast feeding, parity and breast cancer subtypes in a Spanish cohort

BACKGROUND

Differences in the incidence and outcome of breast cancer among Hispanic women compared with white women are well documented and are likely explained by ethnic differences in genetic composition, lifestyle, or environmental exposures. METHODOLGY/PRINCIPAL FINDINGS: A population-based study was conducted in Galicia, Spain. A total of 510 women diagnosed with operable invasive breast cancer between 1997 and 2010 participated in the study. Data on demographics, breast cancer risk factors, and clinico-pathological characteristics were collected. The different breast cancer tumor subtypes were compared on their clinico-pathological characteristics and risk factor profiles, particularly reproductive variables and breastfeeding. Among the 501 breast cancer patients (with known ER and PR receptors), 85% were ER+/PR+ and 15% were ER-&PR-. Among the 405 breast cancer with known ER, PR and HER2 status, 71% were ER+/PR+/HER2- (luminal A), 14% were ER+/PR+/HER2+ (luminal B), 10% were ER-/PR-/HER2- (triple negative breast cancer, TNBC), and 5% were ER-/PR-/HER2+ (non-luminal). A lifetime breastfeeding period equal to or longer than 7 months was less frequent in case patients with TNBC (OR = 0.25, 95% CI = 0.08-0.68) compared to luminal A breast cancers. Both a low (2 or fewer pregnancies) and a high (3-4 pregnancies) number of pregnancies combined with a long breastfeeding period were associated with reduced odds of TNBC compared with luminal A breast cancer, although the association seemed to be slightly more pronounced among women with a low number of pregnancies (OR = 0.09, 95% CI = 0.005-0.54).

CONCLUSIONS/SIGNIFICANCE

In case-case analyses with the luminal A cases as the reference group, we observed a lower proportion of TNBC among women who breastfed 7 or more months. The combination of longer breastfeeding duration and lower parity seemed to further reduce the odds of having a TNBC compared to a luminal A breast cancer.

Haplotype analysis of the 185delAG BRCA1 mutation in ethnically diverse populations

The 185delAG* BRCA1 mutation is encountered primarily in Jewish Ashkenazi and Iraqi individuals, and sporadically in non-Jews. Previous studies estimated that this is a founder mutation in Jewish mutation carriers that arose before the dispersion of Jews in the Diaspora ~2500 years ago. The aim of this study was to assess the haplotype in ethnically diverse 185delAG* BRCA1 mutation carriers, and to estimate the age at which the mutation arose. Ethnically diverse Jewish and non-Jewish 185delAG*BRCA1 mutation carriers and their relatives were genotyped using 15 microsatellite markers and three SNPs spanning 12.5 MB, encompassing the BRCA1 gene locus. Estimation of mutation age was based on a subset of 11 markers spanning a region of ~5 MB, using a previously developed algorithm applying the maximum likelihood method. Overall, 188 participants (154 carriers and 34 noncarriers) from 115 families were included: Ashkenazi, Iraq, Kuchin-Indians, Syria, Turkey, Iran, Tunisia, Bulgaria, non-Jewish English, non-Jewish Malaysian, and Hispanics. Haplotype analysis indicated that the 185delAG mutation arose 750-1500 years ago. In Ashkenazim, it is a founder mutation that arose 61 generations ago, and with a small group of founder mutations was introduced into the Hispanic population (conversos) ~650 years ago, and into the Iraqi-Jewish community ~450 years ago. The 185delAG mutation in the non-Jewish populations in Malaysia and the UK arose at least twice independently. We conclude that the 185delAG* BRCA1 mutation resides on a common haplotype among Ashkenazi Jews, and arose about 61 generations ago and arose independently at least twice in non-Jews.

A deleterious BRCA1 mutation in a young Pakistani woman with metaplastic breast carcinoma

Metaplastic breast carcinoma (MBC) is a relatively rare subtype of breast cancer that encompasses a pathologically heterogeneous group of tumors. Pathogenic germ line mutations in the major breast cancer susceptibility genes BRCA1 and BRCA2 genes have been rarely found or described in MBC. We report the identification of the BRCA1 185delAG mutation in a 22-year-old Pakistani woman with triple-negative MBC that showed biphasic morphological features, including sarcomatous and malignant epithelial components. A comprehensive description of the clinical, histopathological, morphological, and immunohistochemical features of the tumor and the patient's treatment course is presented.

Heterogeneous prevalence of recurrent BRCA1 and BRCA2 mutations in Spain according to the geographical area: implications for genetic testing

BRCA1 and BRCA2 genes have a high allelic heterogeneity. The knowledge of the most prevalent mutations and their geographical distribution can be useful in designing efficient mutational screening. In the present work we reviewed the frequency of BRCA1 and BRCA2 recurrent mutations in seven geographic areas of Spain to evaluate the effects of their heterogeneous prevalence in genetic testing. We observed that prevalence of recurrent mutations vary according to the geographical origin of the studied families, and accounted for a variable number of positive families depending on the series. Therefore, more upcoming data of larger Spanish population cohorts collected from different areas in the country will allow to design a wider comprehensive panel of recurrent mutations that may be applicable worldwide to families with Hispanic origin.

Founder BRCA1/2 mutations in the Europe: implications for hereditary breast-ovarian cancer prevention and control

Detection of mutations in hereditary breast and ovarian cancer-related BRCA1 and BRCA2 genes is an effective method of cancer prevention and early detection. Different ethnic and geographical regions have different BRCA1 and BRCA2 mutation spectrum and prevalence. Along with the emerging targeted therapy, demand and uptake for rapid BRCA1/2 mutations testing will increase in a near future. However, current patients selection and genetic testing strategies in most countries impose significant lag in this practice. The knowledge of the genetic structure of particular populations is important for the developing of effective screening protocol and may provide more efficient approach for the individualization of genetic testing. Elucidating of founder effect in BRCA1/2 genes can have an impact on the management of hereditary cancer families on a national and international healthcare system level, making genetic testing more affordable and cost-effective. The purpose of this review is to summarize current evidence about the BRCA1/2 founder mutations diversity in European populations.

Performance of prediction models for BRCA mutation carriage in three racial/ethnic groups: findings from the Northern California Breast Cancer Family Registry

PURPOSE

Patients with early-onset breast and/or ovarian cancer frequently wish to know if they inherited a mutation in one of the cancer susceptibility genes, BRCA1 or BRCA2. Accurate carrier prediction models are needed to target costly testing. Two widely used models, BRCAPRO and BOADICEA, were developed using data from non-Hispanic Whites (NHW), but their accuracies have not been evaluated in other racial/ethnic populations.

METHODS

We evaluated the BRCAPRO and BOADICEA models in a population-based series of African American, Hispanic, and NHW breast cancer patients tested for BRCA1 and BRCA2 mutations. We assessed model calibration by evaluating observed versus predicted mutations and attribute diagrams, and model discrimination using areas under the receiver operating characteristic curves.

RESULTS

Both models were well-calibrated within each racial/ethnic group, with some exceptions. BOADICEA overpredicted mutations in African Americans and older NHWs, and BRCAPRO underpredicted in Hispanics. In all racial/ethnic groups, the models overpredicted in cases whose personal and family histories indicated >80% probability of carriage. The two models showed similar discrimination in each racial/ethnic group, discriminating least well in Hispanics. For example, BRCAPRO's areas under the receiver operating characteristic curves were 83% (95% confidence interval, 63-93%) for NHWs, compared with 74% (59-85%) for African Americans and 58% (45-70%) for Hispanics.

CONCLUSIONS

The poor performance of the model for Hispanics may be due to model misspecification in this racial/ethnic group. However, it may also reflect racial/ethnic differences in the distributions of personal and family histories among breast cancer cases in the Northern California population.

The average cumulative risks of breast and ovarian cancer for carriers of mutations in BRCA1 and BRCA2 attending genetic counseling units in Spain

PURPOSE

It is not clear that the published estimates of the breast and ovarian cancer penetrances of mutations in BRCA1 and BRCA2 can be used in genetic counseling in countries such as Spain, where the incidence of breast cancer in the general population is considerably lower, the prevalence of BRCA2 mutations seems to be higher, and a distinct spectrum of recurrent mutations exists for both genes. We aimed to estimate these penetrances for women attending genetic counseling units in Spain.

EXPERIMENTAL DESIGN

We collected phenotype and genotype data on 155 BRCA1 and 164 BRCA2 mutation carrier families from 12 centers across the country. Average age-specific cumulative risks of breast cancer and ovarian cancer were estimated using a modified segregation analysis method.

RESULTS

The estimated average cumulative risk of breast cancer to age 70 years was estimated to be 52% [95% confidence interval (95% CI), 26-69%] for BRCA1 mutation carriers and 47% (95% CI, 29-60%) for BRCA2 mutation carriers. The corresponding estimates for ovarian cancer were 22% (95% CI, 0-40%) and 18% (95% CI, 0-35%), respectively. There was some evidence (two-sided P = 0.09) that 330A>G (R71G) in BRCA1 may have lower breast cancer penetrance.

CONCLUSIONS

These results are consistent with those from a recent meta-analysis of practically all previous penetrance studies, suggesting that women with BRCA1 and BRCA2 mutations attending genetic counseling services in Spain have similar risks of breast and ovarian cancer to those published for other Caucasian populations. Carriers should be fully informed of their mutation- and age-specific risks to make appropriate decisions regarding prophylactic interventions such as oophorectomy.

Performance of BRCA1/2 mutation prediction models in Asian Americans

PURPOSE

There are established differences in breast cancer epidemiology between Asian and white individuals, but little is known about hereditary breast cancer in Asian populations. Although increasing numbers of Asian individuals are clinically tested for BRCA1/2 mutations, it is not known whether computer models that predict mutations work accurately in Asian individuals. We compared the performance in Asian and white individuals of two widely used BRCA1/2 mutation prediction models, BRCAPRO and Myriad II.

PATIENTS AND METHODS

We evaluated BRCAPRO and Myriad II in 200 Asian individuals and a matched control group of 200 white individuals who were tested for BRCA1/2 mutations at four cancer genetics clinics, by comparing numbers of observed versus predicted mutation carriers and by evaluating area under the receiver operating characteristic curve (AUC) for each model.

RESULTS

BRCAPRO and Myriad II accurately predicted the number of white BRCA1/2 mutation carriers (25 observed v 24 predicted by BRCAPRO; 25 predicted by Myriad II, P > or = .69), but underpredicted Asian carriers by two-fold (49 observed v 25 predicted by BRCAPRO; 26 predicted by Myriad II; P < or = 3 x 10(-7)). For BRCAPRO, this racial difference reflects substantial underprediction of Asian BRCA2 mutation carriers (26 observed v 4 predicted; P = 1 x 10(-30)); for Myriad II, separate mutation predictions were not available. For both models, AUCs were nonsignificantly lower in Asian than white individuals, suggesting less accurate discrimination between Asian carriers and noncarriers.

CONCLUSION

Both BRCAPRO and Myriad II underestimated the proportion of BRCA1/2 mutation carriers, and discriminated carriers from noncarriers less well, in Asian compared with white individuals.

Genetic analysis of BRCA1 and BRCA2 in breast/ovarian cancer families from Aragon (Spain): two novel truncating mutations and a large genomic deletion in BRCA1

We screened BRCA1 and BRCA2 germline mutations in 60 high-risk breast and/or ovarian cancer patients and 20 relatives from Aragon (Spain) by DHPLC (Denaturing High Performance Liquid Chromatography) and direct sequencing of the entire coding sequence and the splicing sites of both genes. We have identified 17 different pathogenic mutations: 8 in BRCA1 and 9 in BRCA2 in 60 unrelated patients and 50% of relatives were carriers. The prevalence of pathogenic mutations in this study was 33.33%. Two truncating mutations are novel: c.5024_5025delGA in exon 16 of BRCA1 and c.2929delC in exon 11 of BRCA2 (numbered after GenBank U14680 and U43746). Multiplex Ligation Dependent Probe Amplification (MLPA) was performed for large mutational scanning of both genes and a large genomic deletion in BRCA1 was found (DelEx8-13). Furthermore, five mutations are described for the first time in Spanish population: c.1191delC, c.3478_3479delTT and c.6633_6637delCTTAA (BRCA1) and c.3972_3975delTGAG and 3908_3909delTG (BRCA2). Three mutations have been reported previously once in Spain: c.3600_3610del11 (BRCA1), c.5804_5807delTTAA (BRCA2) and c.9246C>A (BRCA2). The mutation c.5374_5377delTATG has been found before only in two unrelated families from Castilla-Leon, Spain (BRCA2). Frequent mutations described in Spanish population have also been present: c.187_188delAG, c.5242C>A and c.5385insC in BRCA1 and c.3492_3493insT and c.9254_9258delATCAT in BRCA2. c.5242C>A, 3972_3975delTGAG and c.5804_5807delTTAA were the recurrent mutations found. Fifteen different unclassified variants were identified (25% families). Although specific BRCA1 and BRCA2 mutations are recurrently reported as a result of genetic founder effects we conclude that heterogeneous ethnicity increases the variety of mutations that can be found in Spanish populations.

Prevalence of BRCA1 and BRCA2 mutations in Pakistani breast and ovarian cancer patients

Among Asian countries, Pakistan has the highest rates of breast and ovarian cancer. To assess the contribution of the BRCA1 and BRCA2 germ line mutations to these high rates, we conducted the first study of 176 Pakistani breast and ovarian cancer patients, selected on family history and on age of diagnosis. Comprehensive BRCA mutation screening was performed using a range of techniques, including denaturing high-pressure liquid chromatography, single strand conformational polymorphism analysis and protein truncation test, followed by DNA sequencing. Thirty deleterious germ-line mutations were identified in the 176 families (17.0%), including 23 in BRCA1 and 7 in BRCA2. Four mutations, 185delAG, 185insA, S1503X and R1835X, were recurrent; these accounted for 52% of all identified BRCA1 mutations. Haplotype analyses suggested founder effects for 3 of these. The prevalence of BRCA1 or BRCA2 mutations was 42.8% for families with multiple cases of breast cancer, and was 50.0% for the breast/ovarian cancer families. The prevalence of mutations was 11.9% for single cases of early-onset breast cancer (< or =30 years) and was 9.0% for single cases of early-onset ovarian cancer (< or =45 years). Our findings show that BRCA mutations account for a substantial proportion of hereditary breast/ovarian cancer and early-onset breast and ovarian cancer cases in Pakistan.

BRCA1 and BRCA2 mutations in a South American population

A sample of 64 high-risk breast and/or ovarian cancer families from Chile were screened for germline mutations in the coding sequences and exon-intron boundaries of BRCA1 (MIN no. 113705) and BRCA2 (MIN no. 600185) genes using conformation-sensitive gel electrophoresis, and the mutations found were confirmed with direct sequencing. Seven families (10.9%) were found to carry BRCA1 mutations and three families (4.7%) had BRCA2 mutations. Six different pathogenic mutations were detected in BRCA1, four that had been reported previously (c.187_188delAG; c.300T-->G, c.3450_3453delCAAG and IVS17-1G-->A) and two novel mutations (c.2605_2606delTT and c.4185_4188delCAAG). In BRCA2, we found three different pathogenic mutations, two previously described (c.6174delT and c.6503_6504delTT) and one novel mutation (c.5667delT). We also identified nine variants of unknown significance (five in BRCA1 and four in BRCA2). These findings indicate that the Chilean population has a heterogeneous spectrum of prevalent BRCA mutations. Given the results obtained in our study, the screening of the entire BRCA1 and BRCA2 coding regions is necessary for the molecular genetic testing of Chilean high-risk breast/ovarian cancer patients. To our knowledge, this is the first genetic study of BRCA gene mutations conducted in Chile. The Chilean population has a well-known admixed Amerindian-Caucasian ratio and, therefore, our findings are not only important per se, but they constitute the basis for improved and more specific genetic counselling, as well as to support for preventive campaigns geared toward the Chilean population.

The Impact of Acculturation on Awareness of Genetic Testing for Increased Cancer Risk among Hispanics in the Year 2000 National Health Interview Survey

Previous studies suggest disparities in use of preventive cancer services among U.S. Hispanics are partly explained by knowledge and access factors. One area of emerging interest is uptake of genetic counseling and testing services by underserved populations. This study aims to estimate the percentage of Hispanics in five ethnic subgroups who are aware of genetic testing for inherited cancer risk, and to assess the influence of acculturation factors primarily related to language on test awareness. Weighted data from 4,313 Hispanic respondents (age >25 years) in the year 2000 National Health Interview Survey were analyzed. Overall, 20.6% of Hispanics had heard of genetic testing for cancer risk, with percentages highest among Puerto Ricans (27.3%) and lowest among Mexicans (14.3%). Completing the interview in Spanish and English [odds ratio (OR), 0.52; 95% confidence interval (95% CI), 0.35-0.78], or only Spanish (OR, 0.60; 95% CI, 0.42-0.86), was inversely associated with test awareness (reference group, only English). Having an intermediate (OR, 0.66; 95% CI, 0.48-0.90) or low (OR, 0.63; 95% CI, 0.39-1.01) level of English language preference was also inversely associated (reference, high level) whereas being born outside the United States was weakly associated (OR, 0.80; 95% CI, 0.57-1.11). Estimates were adjusted for age, education, ethnicity, parents' cancer history, health care access, and selected health behaviors and beliefs. Results of this national survey indicate that acculturation factors related to language may affect cancer genetic test awareness in Hispanics. These factors must be taken into account when informing individuals about the role of genetics in cancer risk and providing cancer genetic health services.

Genes de susceptibilidad al cáncer de mama

Five percent of all cases of breast cancer (BC) show a hereditary component related to gene mutations with an autosomic dominant transmission. To date, few genes are known to be responsible of hereditary BC. The germline mutations of BRCA1 or BRCA2 genes account for less than 50% of families with breast/ovarian cancer predisposition. The large percentage of families with multiple cases of female BC and no BRCA1 and BRCA2 mutations detected could be attributed to the existence of other high or low susceptibility genes acting together with lifestyle risk factors. The predisposition to BC in carriers of ATM mutations has been documented previously. Due to the frequency of ATM heterozygotes in the general population, the mutations in this gene could be associated with up to 5% of BC cases. The mutation 1100delC of the CHEK2 gene seems to be a low penetrance allele of BC susceptibility. The objective of the present manuscript is to review some of the susceptibility genes identified to date.

Prevalence of BRCA mutations and founder effect in high-risk Hispanic families

Approximately 12% of the U.S. population is Hispanic, with the majority residing in urban centers such as Los Angeles. The prevalence of BRCA mutations among high-risk Hispanic families is unknown.

METHODS

One hundred and ten unrelated probands of Hispanic origin, with a personal or family history of breast and/or ovarian cancer, presented for genetic cancer risk assessment, were enrolled in an Institutional Review Board-approved registry and underwent BRCA testing. Haplotype analyses were done if BRCA mutations were observed in two or more unrelated probands.

RESULTS

Mean age at diagnosis was 37 years (range = 23-59) for the 89 (81%) probands with invasive breast cancer. Overall, 34 (30.9%) had deleterious mutations (25 in BRCA1, 9 in BRCA2), 25 (22.7%) had one or more unclassified variants, and 51 (46.4%) had negative results. The mean pretest mutation probability using the Couch model, Myriad model, and BRCAPro was 19.6% (range = 4-77%). The combined average mutation probability was 32.8% for carriers, 15.5% for noncarriers, and 12.9% for variant carriers (P < 0.0001). The most common deleterious mutation was 185delAG (4 of 34, 11.8%). The Hispanic 185delAG carrier families share the same haplotype from D17s1320 through BRCA1, as do two reference Ashkenazi Jewish families. Haplotype analyses of additional recurrent BRCA1 mutations [IVS5+1G>A (n=2),S955X (n = 3), R1443X (n = 3), and 2552delC (n = 2)] also suggest founder effects, with four of six mutations seen almost exclusively in families with Latin American/Caribbean or Spanish ancestry.

CONCLUSION

This is the largest study to date of high-risk Hispanic families in the United States. Six recurrent mutations accounted for 47% (16 of 34) of the deleterious mutations in this cohort. The BRCA1185delAG mutation was prevalent (3.6%) in this clinic-based cohort of predominantly Mexican descent, and shared the Ashkenazi Jewish founder haplotype.

Cancer in Jews: introduction and overview

This article is based upon a literature overview of cancer in Jews. It involves a comparison of variation in incidence and prevalence rates between Jews and non-Jews. However, the reader must exercise a certain amount of skepticism when considering secular changes in cancer incidence and prevalence and the public health implications of such cancer variation. Ashkenazi Jews have a lifetime CRC risk of 9--15%. This elevated CRC risk is similar to that of individuals in the "familial risk'' category, and differs strikingly from the 5-6% CRC risk for non-Ashkenazi members of general Western populations. A MedLine search tested the hypothesis that site-specific and/or all-cancer incidence and mortality rates are either higher or lower than expected in Ashkenazi Jews worldwide, when compared with reference populations. Results showed that all cancer incidence and mortality is not higher in Ashkenazi Jews when compared to North American non-Hispanic whites. Indeed, rates for some cancers, such as carcinoma of the lung in Ashkenazi males, are low; this example is likely attributable in large part to decreased tobacco use. Carcinoma of the ovary, pancreas, stomach, and non-Hodgkin's lymphoma have a higher incidence rate in Ashkenazi. Even though BRCA1 and BRCA2 founder mutations which predispose to carcinoma of the breast and ovary appear increased in Ashkenazi breast cancer affected women, there was no evidence supporting an elevated risk of breast cancer among Ashkenazi women. Our primary concern, however, is that Ashkenazi Jews may have one of the highest lifetime CRC risks of any ethnic group in the world, a risk that diverges significantly from that of the general population; therein, it logically calls for more intensive CRC screening guidelines. We have emphasized that the reader use caution in the interpretation of statistics which portray variation in incidence and prevalence figures for cancer in any racial, ethnic, or religious group, inclusive, of course, of Jews. Clearly, more research will be required in the interest of accuracy in the understanding of these cancer variations, since they portend the need for special cancer control strategies. A lesser degree of attention can then be given to carcinoma of the penis and uterine cervix, which occur very infrequently in Jews. We urge our colleagues to continue to probe further into these statistical differences in cancer's incidence and prevalence in order to garner a better understanding of cancer's etiology and pathogenesis.

Novel germline mutations in breast cancer susceptibility genes BRCA1, BRCA2 and p53 gene in breast cancer patients from India

Mutations in breast cancer susceptibility genes, BRCA1 and BRCA2 account for more than 80% of hereditary breast and ovarian cancers. p53 tumor suppressor gene that controls cellular growth and differentiation is also known to be mutated in more than 50% of human cancers including breast cancer. We have carried out a study on BRCA1 and BRCA2 along with p53 gene mutations in both sporadic as well as familial breast cancer patients from India where breast cancer is fast emerging as a major cancer among premenopausal urban women. We examined 124 untreated primary breast cancer patients comprising 100 sporadic and 24 familial cases including 56 age-matched healthy controls for the presence of BRCA1, BRCA2 and the p53 gene mutations using PCR-SSCP and direct nucleotide sequencing. Certain frequently mutated exons such as 2, 5, 11, 13 and 20 of BRCA1, exons 2, 9, 11 (for 6174delT), 18 and 20 of BRCA2 and 4-9 exons of p53 gene were analyzed in sporadic breast cancer while all 22 coding exons of BRCA1 including its flanking intronic regions along with above mentioned exons of BRCA2 and p53 gene were analyzed in familial breast cancer patients. We identified six patients (25%) with BRCA1 mutation of which three were found to be of novel type one in exon 16 (4956insG) and two in exon 7 (Lys110Thr) (Ser114Pro) out of 24 familial breast cancer patients studied from two different geographic regions/populations of India. Two sisters from a single family (12.5%) out of eight families from Goa with Portuguese colonial origin showed presence of founder Ashkenazi Jewish BRCA1 mutation (185delAG) along with (IVS7 561-34T>C; IVS18 5271 + 66G > A). While from New Delhi, four (25%) of 16 breast cancer families showed BRCA1 mutations; a frame shift protein truncating (4956insG), a transition nonsense (Gln1395Stop) and two amino acid substitutions (Lys110Thr) and (Ser114Pro). Only one (4%) p53 mutation (Val97Ile) in its exon 4 along with BRCA1 mutation (4956insG) could be detected. No major sequence variation in BRCA2 gene was observed except for G203A at 5' UTR of exon 2, a common population polymorphism in two Goan patients who also showed silent nucleotide change for amino acid serine at codon 1436 of BRCA1 gene. None of the 100 sporadic breast cancer patients revealed any protein truncating or deleterious BRCA1 or BRCA2 gene mutation. Interestingly, three (3%) p53 mutations in its exon 5 were detected in sporadic breast cancer patients. Although three novel BRCA1 mutations including a founder Ashkenazi Jewish BRCA1 mutation were recorded in Indian women with familial breast cancer, the overall prevalence of BRCA gene mutations in Indian women with a family history of breast cancer appears to be low.

Analysis of BRCA1 and BRCA2 genes in Spanish breast/ovarian cancer patients: a high proportion of mutations unique to Spain and evidence of founder effects

We screened index cases from 410 Spanish breast/ovarian cancer families and 214 patients (19 of them males) with breast cancer for germ-line mutations in the BRCA1 and BRCA2 genes, using SSCP, PTT, CSGE, DGGE, and direct sequencing. We identified 60 mutations in BRCA1 and 53 in BRCA2. Of the 53 distinct mutations observed, 11 are novel and 12 have been reported only in Spanish families (41.5%). The prevalence of mutations in this set of families was 26.3%, but the percentage was higher in the families with breast and ovarian cancer (52.1%). The lowest proportion of mutations was found in the site-specific female breast cancer families (15.4%). Of the families with male breast cancer cases, 59.1% presented mutations in the BRCA2 gene. We found a higher frequency of ovarian cancer associated with mutations localized in the 5' end of the BRCA1 gene, but there was no association between the prevalence of this type of cancer and mutations situated in the ovarian cancer cluster region (OCCR) region of exon 11 of the BRCA2 gene. The mutations 187_188delAG, 330A>G, 5236G>A, 5242C>A, and 589_590del (numbered after GenBank U14680) account for 46.6% of BRCA1 detected mutations whereas 3036_3039del, 6857_6858del, 9254_9258del, and 9538_9539del (numbered after GenBank U43746) account for 56.6% of the BRCA2 mutations. The BRCA1 330A>G has a Galician origin (northwest Spain), and BRCA2 6857_6858del and 9254_9258del probably originated in Catalonia (northeast Spain). Knowledge of the spectrum of mutations and their geographical distribution in Spain will allow a more effective detection strategy in countries with large Spanish populations.

Identification of germline 185delAG BRCA1 mutations in non-Jewish Americans of Spanish ancestry from the San Luis Valley, Colorado

BACKGROUND

Germline mutations in the BRCA1 and BRCA2 genes are associated with an inherited predisposition to breast and ovarian carcinoma, and specific mutations in these genes are found at increased frequency in certain populations. The authors observed a repeated occurrence of the 185delAG mutation (BRCA1; also known as 187delAG) in a non-Jewish population that originated from the San Luis Valley in Colorado.

METHODS

This was a retrospective analysis of mutations that occur in non-Jewish Americans of Spanish ancestry from Colorado who were tested clinically for BRCA1 and BRCA2 genetic mutations using DNA sequencing.

RESULTS

Between August 1994 and December 2001, 19 Spanish/Latin American individuals from different families underwent genetic counseling and clinical genetic testing using direct DNA sequencing for mutations of the BRCA1 and BRCA2 genes. The results showed that 10 of 19 individuals had mutations or variants of BRCA1 or BRCA2, and 6 of 10 individuals (60%) carried the 185delAG mutation in BRCA1. All six families originated from the San Luis Valley in Colorado, indicated that they were of Spanish/Latin American ethnicity, and denied Jewish ancestry.

CONCLUSIONS

The 185delAG mutation is common in families of non-Jewish ancestry originating from the San Luis Valley in Colorado with hereditary breast/ovarian carcinoma, possibly due to a founder effect. Further investigation may lead to simplified genetic testing and may allow clinicians to serve this population better. The repeated occurrence of the 185delAG mutation in this specific population may have clinical and public health implications.

Haplotype analysis of a BRCA1: 185delAG mutation in a Chilean family supports its Ashkenazi origins

At least 25% of Ashkenazi Jewish families with two or more cases of premenopausal breast cancers are attributable to one of three founder mutations in BRCA1 or BRCA2. As these three founder mutations are common in the Ashkenazi Jewish population ( approximately 2.5%) and can easily be tested for in a multiplex assay, establishing ethnicity can expedite genetic testing. It is not always possible, however, to conclusively establish ethnicity before offering testing. We report here the occurrence of a founder Ashkenazi Jewish BRCA1 mutation, 185delAG (also known as 187delAG), in a non-Jewish Chilean family with no reported Jewish ancestry. The linked haplotype present in this family was identical to that identified in the Ashkenazi Jewish population. This case report not only illustrates the problem of the definition of ethnicity but also points to the possibility of further studies of the frequency of founder Ashkenazi Jewish mutations in populations not generally considered to be of Ashkenazi Jewish origin.

Family history of cancer and germline BRCA2 mutations in sporadic exocrine pancreatic cancer

BACKGROUND

Hereditary factors have been reported in 5-10% of cases with exocrine pancreatic cancer and recent data support a role for BRCA2.

AIMS

We have studied the prevalence of germline BRCA2 mutations in two groups of patients with exocrine pancreatic cancer from an unselected series in Spain: group A included 24 cases showing familial aggregation of cancer and group B included 54 age, sex, and hospital matched cases without such evidence.

METHODS

Information was obtained by interview of patients and was validated by a telephone interview with a structured questionnaire. In patients from group A, >80% of the coding sequence of BRCA2 was analysed; in patients from group B, the regions in which germline BRCA2 mutations have been described to be associated with pancreatic cancer were screened.

RESULTS

Telephone interviews led to reclassification of 7/54 cases (13%). Familial aggregation of cancer was found in 24/165 cases (14.5%); six patients had a first degree relative with pancreatic cancer (3.6%) and nine patients had relatives with breast cancer. Germline BRCA2 mutations were not identified in any patient from group A (0/23). Among group B cases, one germline variant (T5868G>Asn1880Lys) was found in a 59 year old male without a family history of cancer. The 6174delT mutation was not found in any of the 71 cases analysed.

CONCLUSIONS

The overall prevalence of BRCA2 mutations among patients with pancreatic cancer in Spain is low and the 6174delT mutation appears to be very infrequent. Our data do not support screening patients with cancer of the pancreas for germline BRCA2 mutations to identify relatives at high risk of developing this tumour.

Association between BRCA1 and BRCA2 mutations and cancer phenotype in Spanish breast/ovarian cancer families: implications for genetic testing

Index cases from a clinically relevant cohort of 102 Spanish families with at least 3 cases of breast and/or ovarian cancer (at least 1 case diagnosed before age 50) in the same lineage were screened for germline mutations in the entire coding sequence and intron boundaries of the breast cancer susceptibility genes BRCA1 and BRCA2. Overall, the prevalence of mutations was 43% in female breast/ovarian cancer families, 15% in female breast cancer families and 100% in male breast cancer families. Three recurrent mutations (185delAG, 589delCT and A1708E) explained 63% of BRCA1-related families. Early age at diagnosis of breast cancer, ovarian cancer, bilateral breast cancer, concomitant breast/ovarian cancer in a single patient and prostate cancer but not unilateral breast cancer were associated with BRCA1 and BRCA2 mutations. Male breast cancer was associated with BRCA2 mutations. The presence of male breast cancer was the only cancer phenotype that distinguished BRCA2- from BRCA1-related families. We have developed a logistic regression model for predicting the probability of harbouring a mutation in either BRCA1 or BRCA2 as a function of the cancer phenotype present in the family. The predictive positive and negative values of this model were 77.4% and 79%, respectively (probability cutoff of 30%). The findings of our work may be a useful tool for increasing the cost-effectiveness of genetic testing in familial cancer clinics.

High prevalence of the very rare Wilson disease gene mutation Leu708Pro in the Island of Gran Canaria (Canary Islands, Spain): a genetic and clinical study

The molecular basis of Wilson disease (WD), an autosomal recessive disorder, is the presence of mutations in the ATP7B gene, a copper transporting ATPase. Hospital records indicated a higher prevalence of WD (1 in 2,600) in some counties in the northeastern region of the island of Gran Canaria (Canary Islands, Spain) that was around 10-fold higher than that described for European populations (1 in 30,000). The ATP7B gene was analyzed for mutations in 24 affected subjects, revealing a high prevalence of the rare Leu708Pro mutation present in 12 homozygous and 7 heterozygous individuals. In these patients, who constitute one of the largest described cohorts of WD homozygotes, we found a variable clinical presentation of the disease, although the biochemical picture was homogenous and characteristic, thereby confirming that the Leu708Pro change is indeed a mutation associated with WD. Haplotype analysis of subjects homozygous for the Leu708Pro mutation showed a conserved shared region smaller than 1 centimorgan (cM), and the region of linkage disequilibrium between the Leu708Pro mutation and neighboring microsatellite markers extended approximately 4.6 cM. When comparing the amount of linkage disequilibrium versus genetic distance from the disease mutation, it was estimated that a common ancestral Leu708Pro chromosome may have been introduced in Gran Canaria over 56 generations ago, dating it back to pre-Hispanic times. The prevalence, and the tight geographical distribution of the Leu708Pro chromosome suggests that the Canary Islands can be considered a genetic isolate for linkage disequilibrium studies.

Molecular analysis of the BRCA1 and BRCA2 genes in 32 breast and/or ovarian cancer Spanish families

It is estimated that about 5-10% of breast cancer cases may be due to inherited predisposition. Until now, two main susceptibility genes have been identified: BRCA1 and BRCA2. The first linkage and mutational studies suggested that mutations in these two genes would account for the majority of high-risk breast cancer families, but recent studies show how the proportion of families due to BRCA1 or BRCA2 mutations strongly depends on the population and the types of family analyzed. It is now clear that, in the context of families with a modest cancer profile, which are the most commonly found in the clinical practice, the percentage of mutations found is much lower than that suggested by the first studies. In the present study, we analyze a group of 32 Spanish families, which contained at least three cases of female breast cancer (at least one of them diagnosed before the age of 50 years), for the presence of mutations in the BRCA genes. The total proportion of mutations was low (25%), although the percentage of mutations in the BRCA1 and BRCA2 genes was higher, considering the breast and ovarian cancer families and the male breast cancer families respectively. Our results are in agreement with the idea that a great proportion of moderate-risk cancer families could be due to low penetrance susceptibility genes distinct from BRCA1 or BRCA2.

BRCA1 mutation analysis in 83 Spanish breast and breast/ovarian cancer families

A group of 83 Spanish BC/OC families were analysed for BRCA1 germ-line mutations. Analysis of the entire coding sequence was carried out by SSCP and PTT. We identified 5 frameshift mutations: 185delAG (2 times), 189insTGTC, 1241delAC, and 5537delA and 3 missense mutations in BRCA1: 330A > G, 1240C > T, and 5263G > A. The 185delAG mutation was identified in 2 families. One of them was the only Gypsy family participating in our study. All carriers shared the known founder haplotype, although they did not have any Jewish ancestry. Three frameshift mutations were found among the 14 families with 3 or more BC cases and 1 or more OC, which results in a higher percentage (21.4%) of BRCA1 mutations in this group of high risk families. Two missense mutations were found in families with 2 or 3 BC and no OC, indicating a low proportion (4.8%) of mutations in these families. There was no association between bilateral BC and a mutation carrier status. The frequency of BRCA1 involvement is lower than that of any other country hitherto reviewed. Our results highlight the influence of geographical and ethnic origin of the population studied.