Clinical management of women with genomic BRCA1 and BRCA2 mutations*

Purpose. There is increasing evidence that BRCA1 and BRCA2 associated tumors may differ from sporadic cancers. The purpose of this report is to review the current state of knowledge of BRCA1 and BRCA2, the biology of associated tumors, and possible risk reduction strategies in women with these deleterious mutations. Design and methods. We conducted an extensive literature search of all published articles (including Medline) on preclinical data on the function of BRCA1 and BRCA2, associated tumor pathology, and the clinical management for both unaffected carriers and affected patients. Results. BRCA1 and BRCA2 are likely to act as tumor suppressor genes, and together with RAD51 operate in a common DNA damage response pathway implicated in double-strand repair. Breast cancers associated with BRCA1 are frequently of a higher grade, steroid hormone receptor negative, and appear to have a higher proportion of atypical or typical medullary subtype. Conversely, BRCA2 associated breast cancers do not differ significantly from sporadic cancers. No special tumor phenotype has been ascribed to BRCA1 or BRCA2 associated ovarian cancers. Guidelines for risk reduction strategies for the high risk unaffected carrier have been recommended by expert panels in the USA and Europe. Lifestyle changes, multi-modality screening, chemoprevention, and prophylactic oophorectomy and mastectomy, with their possible benefits and attendant risks are described. Finally, locoregional and systemic treatment in breast and ovarian cancers associated with these mutations, and differences between these and sporadic cancers are discussed. Conclusions. Although the incidence of breast or ovarian cancers that can be attributed to BRCA1 or BRCA2 mutations account for less than 5% of all cancers, these cancers may differ from sporadic cases in terms of tumor biology and phenotype. These differences may impact directly on clinical management of breast and ovarian cancer patients, and their relatives. Further recommendations of these patients are constantly changing as new information emerges on the clinical behavior of these cancers.     

Peritoneal carcinoma in women with genetic susceptibility: implications for Jewish populations

Women from families with multiple cases of breast and ovarian cancer, specifically those who carry cancer-associated mutations of BRCA1or BRCA2are at increased life-time risk for peritoneal carcinoma, even after previous surgery to remove the ovaries, fallopian tubes and uterus. Hereditary breast–ovarian cancer (HBOC) syndrome and the associated BRCA1and BRCA2mutations are particularly prevalent in women of Jewish lineage, and specific BRCA1and BRCA2germline mutations have been linked with peritoneal carcinoma and HBOC syndrome in Jewish populations, especially those of Ashkenazi descent. This review presents the currently available data and looks forward toward further and better understanding of peritoneal carcinoma in women with inherited susceptibility. Over 90% of peritoneal cancer in patients from HBOC syndrome kindreds and associated with BRCA1and BRCA2mutations are serous carcinomas, which is equivalent with the proportion of ovarian cancers that are serous carcinomas in similar patients. The best indications are that while many peritoneal carcinomas in genetically susceptible women may arise directly from malignant transformation of the peritoneum, others might represent metastases from primary ovarian or fallopian tube carcinomas. Although the incidence of borderline ovarian tumors may not be increased in HBOC syndrome kindreds and those who carry cancer-associated BRCA1and BRCA2mutations, these individuals could be susceptible to malignant transformation of borderline lesions of the ovaries and peritoneum. Moreover, recent reports raise the question of possibly increased risk in Jewish carriers of germline BRCA1mutations for uterine papillary serous carcinoma, which could be the source of metastasis to the peritoneum in some cases. The penetrance of cancer-associated BRCA1mutations for ovarian cancer is estimated to be 11%–54%, and for BRCA2mutations the penetrance for ovarian cancer is 11%–23%. So far, available screening methods appear to be insufficient for early detection of many ovarian cancers. Prophylactic oophorectomy has been found to reduce the risk for ovarian cancer in women from HBOC kindreds and those who carry cancer-associated BRCA1and BRCA2mutations, leaving a residual risk for peritoneal carcinomatosis of well less than 5%. Therefore, surgical removal of the ovaries, fallopian tubes and uterus, after child-bearing has been completed and by early in the fifth decade of life, are appropriate prophylactic procedures in women whose genetic susceptibility puts them at increased risk for cancers of mullerian tract origin, including ovarian and fallopian tube carcinomas and possibly serous carcinoma of the uterus. Hysterectomy, as well as salpingo-oophorectomy, removes the gynecologic organs targeted for malignant transformation in genetically susceptible women and simplifies decisions regarding hormone replacement therapy and chemical prophylaxis and treatment of breast cancer. Unless a transabdominal operative approach is otherwise indicated, laparoscopic-assisted transvaginal techniques are well suited for intra-abdominal exploration, cytology, biopsies and prophylactic salpingo-oophorectomy and hysterectomy in women with hereditary susceptibility to gynecologic cancer.     

The prevalence of BRCA1 and BRCA2 germline mutations in high-risk breast cancer patients of Chinese Han nationality: two recurrent mutations were identified

To have an overview of the role of BRCA1 and BRCA2 genes among Chinese high-risk breast cancer patients, we analyzed 489 such high-risk breast cancer patients from four breast disease clinical centers in China, by using PCR-DHPLC or SSCP-DNA sequencing analysis. Allelotype analysis was done at five short tandem repeat (STR) markers in or adjacent to BRCA1 on the recurrent mutation carriers. For those analyzed both genes, 8.7% of early-onset breast cancer cases and 12.9% of familial breast cancer cases had a BRCA1 or BRCA2 mutation, as compared with the 26.1% of cases with both early-onset breast cancer and affected relatives. For those reporting malignancy family history other than breast/ovarian cancer, the prevalence of BRCA1/2 mutation is about 20.5%, and it was significantly higher than the patients only with family history of breast/ovarian cancer (P = 0.02). The family history of ovarian cancer (26.7% vs. 11.9%) and stomach cancer (23.8% vs. 11.8%) doubled the incidence of BRCA1/2, but the difference did not reach the statistical significance. Two recurrent mutations in BRCA1, 1100delAT and 5589del8, were identified. The recurrent mutations account for 34.8% BRCA1 mutations in our series. Similar allelotypes were detected in most STR status for those harboring the same mutations. The BRCA1 associated tumors were more likely to exhibit a high tumor grade, negative C-erbB-2/neu status and triple negative (ER, PgR and C-erbB-2/neu negative) status (P < 0.05). We recommended the BRCA1 and BRCA2 genetic analysis could be done for high-risk breast cancer patient in Chinese population, especially for those with both early-onset breast cancer and affected relatives. There may be some degree of shared ancestry for the two recurrent BRCA1 mutations in Chinese. Wen-Feng Li and Zhen Hu have contributed equally to this work.     

Nuclear morphometric features in benign breast tissue and risk of subsequent breast cancer

Germ-line mutations in BRCA1 and BRCA2 are responsible for about 30–60% of the hereditary breast and ovarian cancer (HBOC). A large number of point mutations have been described in both genes. However, large deletions and duplications that disrupt one or more exons are overlooked by point mutation detection approaches. Over the past years several rearrangements have been identified in BRCA1, while few studies have been designed to screen this type of mutations in BRCA2. Our aim was to estimate the prevalence of large genomic rearrangements in the BRCA2 gene in Spanish breast/ovarian cancer families. The multiplex ligation-dependent probe amplification (MLPA) was employed to search gross deletions or duplications of BRCA2 in 335 Spanish moderate to high-risk breast/ovarian cancer families previously screened negative for point mutations by conventional methods. Four different and novel large genomic alterations were consistently identified by MLPA in five families, respectively: deletions of exon 2, exons 10–12 and exons 15–16 and duplication of exon 20 (in two families). RT-PCR experiments confirmed the deletion of exons 15–16. All patients harbouring a genomic rearrangement were members of high-risk families, with three or more breast/ovarian cancer cases or the presence of breast cancer in males. We provide evidence that the BRCA2 rearrangements seem to account for a relatively small proportion of familial breast cancer cases in Spanish population. The screening for these alterations as part of the comprehensive genetic testing can be recommended, especially in multiple case breast/ovarian families and families with male breast cancer cases.     

A review of histopathological subtypes of ovarian cancer in BRCA-related French Canadian cancer families

Pathogenic mutations in BRCA1 and BRCA2 have been reported in about 55–59% of breast and ovarian cancer (HBOC) families of French Canadian descent, where about 70% of families with more than two cases of ovarian cancer were mutation-positive. Given that specific subtypes of ovarian cancer are associated with mutation-positive families, we reviewed the features of 54 HBOC families of French Canadian descent that had histopathologically confirmed cases of invasive ovarian cancer where the BRCA1 and BRCA2 mutation status is known, and 27 families harbored germline mutations. The number of cases and ages of diagnosis of either breast cancers or ovarian cancers did not differ significantly in comparisons of mutation-positive and mutation-negative groups. However, the distribution of histopathological subtypes for the 79 cases of invasive epithelial cancer from the 54 HBOC families differed when grouped according to familial mutation status. The mutation-negative group had significantly more cases of the mucinous subtype of ovarian cancer when compared with the BRCA1 (P = 0.005) and BRCA2 (P = 0.017) mutation-positive groups. The presence of a mucinous subtype ovarian cancer in multiple young age of onset breast and/or ovarian mutation-negative HBOC cancer families warrants further investigation, as these families appear to exhibit features most consistent with BRCA1 and BRCA2 carrier status.     

High Incidence of 4153delA <Emphasis Type="Italic">BRCA1</Emphasis> Gene Mutations in Lithuanian Breast- and Breast-ovarian Cancer Families

Summary BRCA1 and BRCA2 gene mutations confer a high lifetime risk to breast and ovarian cancers. We have screened cancer patients from 13 families with at least three breast and/or ovarian cancers from Lithuania for 5382insC, C61G and 4153delA BRCA1 gene mutations. One of three mutations was found in 9 of the 13 studied families (69%). 4153delA was the most frequently detected and accounted for 56% of all identified mutation. 5382insC and C61G accounted for 33% and 11% of found mutations, respectively. Significantly higher, than in other populations, incidence of 4153delA indicates that this may be founder BRCA1 mutation characteristic for Lithuanians. Our analysis shows that testing of 4153delA, 5382insC, C61G BRCA1 mutations should be extremely effective and inexpensive tool in testing Lithuanian population aimed to identify individuals with high risk of breast and ovarian cancers.     

BRCA1 and BRCA2 germline mutational spectrum and evidence for genetic anticipation in Portuguese breast/ovarian cancer families

We present the first characterisation of the mutational spectrum of the entire coding sequences and exon–intron boundaries of the BRCA1 and BRCA2 genes as well as large BRCA1 rearrangements in Portuguese families with inherited predisposition to breast/ovarian cancer. Of the 100 probands studied, pathogenic mutations were identified in 22 (24.7%) of 89 breast and/or ovarian cancer families with more than one affected member (15 in BRCA1 and seven in BRCA2), but in none of the 11 patients without family history of cancer. One (6.7%) of the BRCA1 mutations is a large deletion involving exons 11–15. Seven pathogenic point mutations are novel: 2088C>T, 2156delinsCC, and 4255_4256delCT in BRCA1 and 4608_4609delTT, 5036delA, 5583_5584insT, and 8923C>T in BRCA2. The novel 2156delinsCC was identified in three probands from different families and probably represents a founder mutation in our population. We also found a previously reported 3450_3453del4 mutation in three unrelated patients. In addition to the 22 pathogenic mutations, we identified 19 missense mutations of uncertain pathogenic significance, three of them (5241G>C in BRCA1 and IVS6+13C>T and 3731T>C in BRCA2) previously undescribed. The percentage of cases with truncating mutations in BRCA1 and BRCA2 was higher in breast/ovarian cancer (37.0%, mostly BRCA1) and male breast cancer (40%, all BRCA2) families than in families with only female breast cancer (17.5%). Interestingly, we found evidence for genetic anticipation regarding age at diagnosis of both breast and ovarian cancer in those families presenting affected members in more than one generation. These findings should be taken into consideration while planning screening and prophylactic measures in families with inherited predisposition to breast and ovarian cancer.     

A high frequency of germline <Emphasis Type="Italic">BRCA1/2</Emphasis> mutations in western Sweden detected with complementary screening techniques

Dominant inheritance is presumed in 6–10% of breast and ovarian cancers. Mutations in BRCA1 and BRCA2 genes are the most commonly identified causative genes in such families. The frequency of mutation carriers with breast/ovarian cancer depends on the population studied, and display considerable variation that coincides with ethnic and geographical diversity. Mutation analyses were performed in 143 families registered at the Cancer Genetic Counseling Clinic of western Sweden. In a thorough mutation screening procedure, the entire BRCA1 and BRCA2 genes were analyzed using a combination of complementary mutation detection techniques. Mutations in either BRCA1 or BRCA2 were detected in 36% (52 out of 143) of all screened families. All families were clinically evaluated regarding age at diagnosis, type of cancer and number of cancer cases in the family. Among high-risk families, the mutation detection rate was 39% (46 out of 117). The detection rate observed among families with cases of ovarian cancer (42 out of 62, 68%), was substantially higher than in families with only breast cancer (10 out of 81, 12%). Age at ovarian cancer did not seem to have an effect on the detection rate. The analyses revealed 11 frameshift mutations, 4 nonsense mutations and 2 large deletions. Notably, the BRCA1 c.3171ins5 mutation accounted for 34 of 52 (65%) identified mutations. Seven mutations are novel: BRCA1c.409_410del; c.1912T>G; c.2228_2229del; c.3029delA; c.3433delA, a large deletion covering exons 1–3 of BRCA1and one BRCA2 mutation; BRCA2c.6287_6290del. We have shown that the founder mutation BRCA1 c.3171ins5 has a great influence on western Swedish breast/ovarian cancer families along with a high number of mutations unique for the region. In order to achieve a high mutation detection rate we suggest a combination of several detection techniques.     

Genomic analysis of inherited breast cancer among Palestinian women: Genetic heterogeneity and a founder mutation in TP53

Breast cancer among Palestinian women has lower incidence than in Europe or North America, yet is very frequently familial. We studied genetic causes of this familial clustering in a consecutive hospital‐based series of 875 Palestinian patients with invasive breast cancer, including 453 women with diagnosis by age 40, or with breast or ovarian cancer in a mother, sister, grandmother or aunt (“discovery series”); and 422 women diagnosed after age 40 and with negative family history (“older‐onset sporadic patient series”). Genomic DNA from women in the discovery series was sequenced for all known breast cancer genes, revealing a pathogenic mutation in 13% (61/453) of patients. These mutations were screened in all patients and in 300 Palestinian female controls, revealing 1.0% (4/422) carriers among older, nonfamilial patients and two carriers among controls. The mutational spectrum was highly heterogeneous, including pathogenic mutations in 11 different genes: BRCA1, BRCA2, TP53, ATM, CHEK2, BARD1, BRIP1, PALB2, MRE11A, PTEN and XRCC2. BRCA1 carriers were significantly more likely than other patients to have triple negative tumors (p = 0.03). The single most frequent mutation was TP53 p.R181C, which was significantly enriched in the discovery series compared to controls (p = 0.01) and was responsible for 15% of breast cancers among young onset or familial patients. TP53 p.R181C predisposed specifically to breast cancer with incomplete penetrance, and not to other Li‐Fraumeni cancers. Palestinian women with young onset or familial breast cancer and their families would benefit from genetic analysis and counseling.     

BRCA1/BRCA2 mutation status and clinical-pathologic features of 108 male breast cancer cases from Tuscany: a population-based study in central Italy

Background Male breast cancer (MBC) is a rare and scarcely investigated disease. The strongest genetic risk factor for MBC is represented by inherited BRCA2 mutations, whereas the association between MBC and BRCA1 mutations is less clear. MBC appears to be biologically similar to breast cancer in females, however the phenotypic characteristics of BRCA1/2-related MBCs are not yet well elucidated. Objective To investigate the genetic and phenotypic characteristics of MBC in a large and well-characterized population-based series of 108 MBCs from Tuscany (Central Italy) and to evaluate associations between BRCA1/BRCA2 mutation status and clinical-pathological features including breast/ovarian cancer first-degree family history, tumor histology and grade, proliferative activity, estrogen/progesterone receptors (ER/PR) and epidermal growth factor receptor 2 (HER2) expression. Results BRCA1/BRCA2 mutations were identified in ten MBCs, in particular, two cases (1.9%) carried BRCA1 and eight cases (7.4%) carried BRCA2 mutations. The same BRCA1 mutation (3347delAG) was detected in two unrelated MBC cases. Three novel BRCA2 pathogenic mutations were found. Statistically significant associations emerged between BRCA2-related tumors and absence of PR expression (P = 0.008), HER2 over-expression (P = 0.002) and high tumor grade (P = 0.005). Conclusions Here, we (i) reported that in our population about 9% of MBC cases are accounted for by BRCA1/BRCA2 mutations; (ii) enlarged the BRCA2 mutational spectrum and (iii) characterized a specific phenotype associated with BRCA2-related MBCs suggestive of aggressive behavior. Overall, our results may have important implications on clinical management for this rare disease.     

BRCA2, but not BRCA1, mutations account for familial ovarian cancer in Iceland: a population-based study

A single founder mutation in each of the BRCA genes has been identified in Iceland. The frequency of the BRCA1 G5193A and BRCA2 999del5 mutations in all ovarian cancer patients diagnosed over the period 1991–2000 was determined. Mutation status was correlated with family history, tumour morphology and age at diagnosis. Samples from 86% of cases (179 carcinomas and 74 borderline tumours) were available. In the carcinomas, BRCA1 and BRCA2 mutations were present in 1.2% and 6% of cases, respectively. No BRCA mutations were found in the borderline tumours. Odds Ratio (OR) of developing ovarian cancer was 20.65 for BRCA2 carriers. Family history of breast/ovarian cancer was present for 70% of BRCA2 carriers and approximately 14% for non-carriers with carcinoma. In conclusion, BRCA2 999del5 is present in 6% of ovarian cancer cases in Iceland and is associated with a 20-fold increase in the risk of the disease. The BRCA1 G5193A mutation is too rare to contribute significantly to ovarian cancer in Iceland.     

Hereditary ovarian cancer in Ashkenazi Jews

Ovarian cancer is the fourth leading cause of cancer deaths among American women. While women in both the Ashkenazi and non-Ashkenazi populations have an estimated 1.7% lifetime risk of acquiring malignancy, the proportion of hereditary ovarian cancer is much higher in the Ashkenazim. Most of this increased proportion of hereditary ovarian cancer risk is accounted for by inherited mutations in the BRCA1 and BRCA2 genes. In the Ashkenazi Jewish population, 29 to 41% of ovarian cancer is believed to be secondary to inheriting one of three founder mutations in BRCA1 and BRCA2, while only 10% of ovarian cancer is attributed to mutations of these genes in non-Ashkenazim. In the US population in general, it is estimated that between 1 out of 345 and 1 out of 1000 individuals carries a BRCA mutation, compared with approximately 1 in 40 individuals of Ashkenazi Jewish descent. The ovarian cancer risk up to age 70 associated with BRCA mutation carriers has been reported to be as high as 66% for BRCA1 and 27% for BRCA2mutation carriers. Ovarian cancer in Ashkenazi kindreds has served as a model for the study of the histopathology of inherited ovarian cancers as well as for the study of risk reduction and screening among all women at inherited risk of ovarian cancer.     

Association of the C677T polymorphism in the MTHFR gene with breast and/or ovarian cancer risk in Jewish women

The C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene is associated with reduced enzyme activity, hyperhomocysteinaemia and increased risk for atherosclerosis in homozygotes. We examined the frequency of this mutation and its association with disease pattern in 491 Jewish women with either sporadic (n=355; 72%) or hereditary (n=136; 28%) breast and/or ovarian cancer and in 69 asymptomatic BRCA1/2 mutation carriers, genotyped for the three predominant Jewish founder BRCA1/2 mutations (185delAG, 5382insC and 6174delT). 677T homozygotes were equally distributed among women with sporadic breast and/or ovarian cancer (71/355; 20.0%) and among BRCA1/2 mutation carriers (43/205; 21.0%) (P=non-significant). 677T homozygotes were equally distributed among women diagnosed with breast cancer prior to (22/122; 18.0%) and after 42 years of age (42/243; 17.3%). Among BRCA1/2 carriers, the rate of 677T homozygotes in manifesting cancer (32/136; 23.5%) and asymptomatic individuals (11/69; 15.9%) was not significantly different. The rate of 677T homozygotes (24/72; 33.3%) was higher (P=0.0026) among women with bilateral breast cancer and those with both breast and ovarian carcinoma than among those with unilateral breast cancer (64/365; 17.5%). Differences in morbidity (one versus multiple breast/ovarian tumours) are mainly attributed to 677T homozygosity and partly to BRCA1/2 mutations. Confirmation of these data, namely, that the 677T allele is significantly more common in cases of bilateral breast cancer or combined breast and ovarian cancer would have important clinical implications.     

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 527166G>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.     

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.     

BRCA1 and BRCA2 Mutations in Breast and Ovarian Cancer Syndrome: Reflection on the Creighton University Historical Series of High Risk Families

Over the last four decades, Henry Lynch has collected pedigrees and samples from high risk breast and/or ovarian cancer families, generating a unique resource for the study of breast cancer susceptibility. These families have made a major contribution to increasing our knowledge in the cancer genetic susceptibility field, allowing the discovery of a genetic association between breast and ovarian cancer predisposition, contributing to the mapping of the BRCA1 and BRCA2 genes, advancing the idea of the existence of other breast cancer susceptibility genes, allowing the evaluation of BRCA-associated cancer risks and psychosocial aspects of BRCA testing and so on. Ten years after the cloning of BRCA1 and BRCA2, we report the current status of these families and compare the observed BRCA1/2 mutation detection rate with the estimations obtained by linkage analysis of the Breast Cancer Linkage Consortium families.     

中国汉族BRCA1/2突变的乳腺癌家系中其他肿瘤发病风险分析

目的 研究携带BRCA1/2突变的中国汉族家族性乳腺癌家系中非乳腺癌和卵巢癌的其他肿瘤发病风险.方法 采用聚合酶链反应(PCR)-直接测序法检测465个汉族家族性乳腺癌家系中先证者的BRCA1/2基因胚系突变,比较突变组与非突变组有非乳腺癌和卵巢癌的其他肿瘤家族史的比例.结果 在465例汉族家族性乳腺癌先证者中,BRCA1/2突变者47例(10.1％),非突变者418例(89.9％).在BRCA1/2突变组和非突变组中,两者总的非乳腺癌和卵巢癌的其他肿瘤家族史比例差异无统计学意义(突变组与非突变组,27.7％∶29.9％,x2=0.10,P=0.75);但两组的瘤谱分布有差别,在突变组的家族中最常见肿瘤为胃癌、胰腺癌和前列腺癌;而在非突变组家族中最常见的为肺癌、胃癌和食管癌.进一步分析发现胃癌、胰腺癌和前列腺癌3种肿瘤家族史总的比例在突变组中显著高于非突变组(突变组与非突变组,17％∶7.7％,Fisher精确概率法P=0.048).突变组家族中发生胃癌、胰腺癌和前列腺癌的风险为非突变组家族的2.47倍(95％ CI为1.07 ～ 5.74).结论 在中国汉族家族性乳腺癌患者中,相比较于非BRCA1/2突变家系,BRCA1/2突变患者的家系有相对较高的风险发生胃癌、胰腺癌和前列腺癌.     

Greek BRCA1 and BRCA2 mutation spectrum: two BRCA1 mutations account for half the carriers found among high-risk breast/ovarian cancer patients

127 Greek breast/ovarian cancer families were screened for germline BRCA1/2 mutations by dHPLC followed by direct sequencing. Our results indicated 16 and 5 breast/ovarian cancer families bearing deleterious mutations in the BRCA1 and BRCA2 genes, respectively. Two novel BRCA2 germline mutations (G4X and 3783del10) are reported here for the first time. Subsequent compilation of our present findings with previously reported mutation data reveals that in a total of 287 Greek breast/ovarian cancer families, 46 and 13 carry a deleterious mutation in BRCA1 and BRCA2, respectively. It should be noted that two BRCA1 mutations, 5382insC and G1738R, both located in exon 20, account for 46% of the families found to carry a mutation. Based on our mutation analysis results, we propose here a hierarchical, cost-effective BRCA1/2 mutation screening protocol for individuals of Greek ethnic origin. The suggested protocol can impact on the clinical management of breast-ovarian cancer families on a national healthcare system level. Irene Konstantopoulou and Theodore Rampias equally contributed to this work.     

Twenty-three novel BRCA1 and BRCA2 sequence alterations in breast and/or ovarian cancer families of Eastern Spain

It is well established that mutations in BRCA1 and BRCA2 genes significantly increase the risk of breast and ovarian cancer. We here report 23 novel genetic variants of the BRCA1 and BRCA2 genes found in 349 cancer-prone unrelated families from Eastern Spain detected during the first 2 years of performance of the Program of Genetic Counseling of Valencia Community. Mutational screening was performed by pre-screening the heteroduplex formed in the PCR products obtained amplifying BRCA1 and BRCA2 genes by conformation sensitive electrophoresis. We detected 10 deletereous mutations, four in BRCA1 (three frame-shift (FS) and one nonsense mutation (NS)) and six in BRCA2 (four FS and one NS mutation). Moreover, we detected 13 unclassified variants, four in BRCA1 (one missense (MS), two synonymous (SYN) and one intronic (I) variant) and nine in BRCA2 (six MS, one SYN and two I). The relevance of the novel mutations is discussed. Our contribution broadens the BRCA1/2 world mutational spectra.