Eva Esteban Cardeñosa

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.

Mutaciones de BRCA1 y BRCA2 en familias estudiadas en el Programa de Consejo Genético en el Cáncer de la Comunidad Valenciana

BACKGROUND AND OBJECTIVE: The objective of the present study was to investigate the mutational spectrum of BRCA1 and BRCA2 in the Valencian Community, comparing this spectrum with that reported in Spain. We also analyze the association of the mutations with the family history of the selected families. PATIENTS AND METHOD: We analyzed the mutations in the BRCA1 and BRCA2 in 147 families with history of breast and/or ovarian cancer. The detection was based on the amplification of in frame and flanking regions of BRCA1 and BRCA2 genes by polymerase chain reaction, detection of the heteroduplex formed by conformation-sensitive gel electrophoresis and their characterization by sequencing. RESULTS: We identified 24 different pathogenic mutations in 50 out of the 147 families (34.0%; 23 in BRCA1 and 27 in BRCA2). The higher incidence of pathogenic mutations was observed in families with breast and ovarian cancer or with more than 3 cases of breast cancer. The most frequent mutations in BRCA1 were the c.187_188delAG, c.2080delA and the c.3889_3890delAG, whereas for BRCA2 the mutations with higher prevalence was observed for c.9254_9258delATCAT and the c.9204delCATCAGATTTATAT. We detected 5 pathogenic mutations (p.Y1429X in BRCA1 and c.1835insT, c.5025delT, c.6722delT and p.Q3156X in BRCA2) not reported in the Breast Cancer Information Core Database. Among them, the BRCA2 mutations c.1835insT and c.5025delT were recurrent and seemed to be characteristic of the population the Valencian Community. CONCLUSIONS: We detected pathogenic mutations in BRCA1 and BRCA2 genes in 34.0% of the families studied. The mutations c.1835insT and c.5025delT were 2 new recurrent pathogenic mutations in BRCA2 that seemed to be characteristic of the population of the Valencian Community. The study reports 5 new pathogenic mutations to the world spectrum of BRCA1 and BRCA2 mutations and other 5 mutations to the Spanish spectrum.

Identification of a novel BRCA1 large genomic rearrangement in a Spanish breast/ovarian cancer family

Background Alterations in BRCA1 gene are responsible for the majority of hereditary breast and/or ovarian cancers. However, the frequency of detected germline mutations is lower than expected by linkage analysis. Standard PCR-based screening methods are mainly used for detecting mutations, but the large genomic rearrangements are commonly overlooked. The purpose of this study was to confirm and characterize a novel deletion identified in BRCA1 gene which has not yet been reported to date. Methods Multiplex ligation-dependent probe amplification was used to analyze BRCA1 rearrangements in 255 unrelated index patients with familial breast and/or ovarian cancer negative for BRCA1/BRCA2 mutations studied in Program of Genetic Counselling on Cancer of Valencia Community (Spain). The breakpoints of detected novel rearrangement were characterized by sequencing. Results and discussion Five different rearrangements in the BRCA1 gene were identified in five unrelated index patients out of the 225 (2%). We found four large genomic rearrangements already described consisting in a 1A/1B and 2 deletion; deletion of exons 5–7; deletion of exons 8–13; exon 20 deletion. Additionally, we found the novel g.8097_22733del14637 deletion that encompasses exons 3–5. This deletion affects the RING domain of the BRCA1 protein and it is suggestive of having a negative impact on its function. Conclusion The new mutation here reported broadens the mutational spectrum of large rearrangements. Furthermore, the five large rearrangements found in patients non-carriers of BRCA1/BRCA2 mutations reinforce the need of studying BRCA1 large genomic rearrangements in genetic counselling programs.Background Alterations in BRCA1 gene are responsible for the majority of hereditary breast and/or ovarian cancers. However, the frequency of detected germline mutations is lower than expected by linkage analysis. Standard PCR-based screening methods are mainly used for detecting mutations, but the large genomic rearrangements are commonly overlooked. The purpose of this study was to confirm and characterize a novel deletion identified in BRCA1 gene which has not yet been reported to date. Methods Multiplex ligation-dependent probe amplification was used to analyze BRCA1 rearrangements in 255 unrelated index patients with familial breast and/or ovarian cancer negative for BRCA1/BRCA2 mutations studied in Program of Genetic Counselling on Cancer of Valencia Community (Spain). The breakpoints of detected novel rearrangement were characterized by sequencing. Results and discussion Five different rearrangements in the BRCA1 gene were identified in five unrelated index patients out of the 225 (2%). We found four large genomic rearrangements already described consisting in a 1A/1B and 2 deletion; deletion of exons 5–7; deletion of exons 8–13; exon 20 deletion. Additionally, we found the novel g.8097_22733del14637 deletion that encompasses exons 3–5. This deletion affects the RING domain of the BRCA1 protein and it is suggestive of having a negative impact on its function. Conclusion The new mutation here reported broadens the mutational spectrum of large rearrangements. Furthermore, the five large rearrangements found in patients non-carriers of BRCA1/BRCA2 mutations reinforce the need of studying BRCA1 large genomic rearrangements in genetic counselling programs.

Broad BRCA1 and BRCA2 mutational spectrum and high incidence of recurrent and novel mutations in the eastern Spain population.

It is well known that the pathogenic mutations in BRCA1 or BRCA2 genes are detected in 5–10% of total breast (BC) and ovarian cancer (OC) and in 20–30% of BC/OC found in families with strong history of cancer [1]. However, the incidence of the BRCA1 and BRCA2 pathogenic mutations depends on the criteria adopted to select the families to be studied [2], and the mutation spectrum varies considerable due to the influence of the ethnic groups [3]. In addition, ethnicity could substantiate the appearance of founder mutations coming from an old ancestor such as the recurrent mutations detected among Ashkenazim [4, 5]. The Program of Genetic Counselling in Cancer of Valencia Community was launched in March 2005 and we reported the results of the first 147 nonrelated families included, describing the preliminary mutational spectrum [6] and novel mutations [7]. However, since then, the number of subjects studied for BRCA1 and BRCA2 mutations has increased considerably having reached the 704 families at the end of 2008. This large number of individuals prompted us to update our series and to establish a consistent mutational spectrum of the population of Eastern Spain identifying the recurrent mutations and relevance of the novel mutations. We studied 704 index patients (IP) (689 females and 15 males) who enrolled in the Program of Genetic Counselling in Cancer of the Valencian Community from March 2005 to December 2008. The IPs were selected by the Units of Genetic Counselling in Cancer (UGCC) according to the inclusion criteria established in the Program of Genetic Counselling in Cancer for familial BC/OC [8, 9]. All the individuals signed a written consent elaborated by the Conselleria de Sanitat (Valencia Community) in accordance with the Helsinki Declaration (1964, amended in 1975 and 1983) [10]. BRCA1 and BRCA2 mutations were detected by amplifying all the exons and the exon–intron boundaries of both genes by PCR using the primer pairs and the PCR conditions reported in the Breast Cancer Information Core (BIC) [11]. To identify the genetic variations, we carried out a pre-screening of the heteroduplexes of the PCR products by conformation sensitive gel electrophoresis (CSGE) [12] followed by the sequencing of the PCR products in which heteroduplexes were identified. In BRCA1, we found 26 different deleterious mutations in 62 IPs (17 frameshift, 3 splicing, 4 nonsense, and 2 missense mutations; Table 1); 16 of these mutations have been This study was conducted on behalf of the Group for Assessment for Hereditary Cancer of Valencian Community.