BRCA1 and BRCA2 mutations in Ashkenazi Jewish families with breast and ovarian cancer

Challenges in Diversity, Equity, and Inclusion in Research and Clinical Oncology

Disparities are common and well-known in the field of clinical oncology and cancer research. In patient care, poor access and a number of other factors disadvantage patients and this can lead to inadequate screening, prevention or treatment of cancer and poor patient outcomes. World-wide, socioeconomic status, health care expenditures and a number of other challenges contribute to disparities in cancer care and patient outcomes. Access to cancer clinical trials remains inadequate for underrepresented minorities as well as non-white racial and ethnic groups. There are also disparities and many challenges in the biomedical research enterprise that can limit innovation and that must be addressed as part of active interventions.

A multilevel model of postmenopausal breast cancer incidence

BACKGROUND

Breast cancer has a complex etiology that includes genetic, biologic, behavioral, environmental, and social factors. Etiologic factors are frequently studied in isolation with adjustment for confounding, mediating, and moderating effects of other factors. A complex systems model approach may present a more comprehensive picture of the multifactorial etiology of breast cancer.

METHODS

We took a transdisciplinary approach with experts from relevant fields to develop a conceptual model of the etiology of postmenopausal breast cancer. The model incorporated evidence of both the strength of association and the quality of the evidence. We operationalized this conceptual model through a mathematical simulation model with a subset of variables, namely, age, race/ethnicity, age at menarche, age at first birth, age at menopause, obesity, alcohol consumption, income, tobacco use, use of hormone therapy (HT), and BRCA1/2 genotype.

RESULTS

In simulating incidence for California in 2000, the separate impact of individual variables was modest, but reduction in HT, increase in the age at menarche, and to a lesser extent reduction in excess BMI >30 kg/m(2) were more substantial.

CONCLUSIONS

Complex systems models can yield new insights on the etiologic factors involved in postmenopausal breast cancer. Modification of factors at a population level may only modestly affect risk estimates, while still having an important impact on the absolute number of women affected.

IMPACT

This novel effort highlighted the complexity of breast cancer etiology, revealed areas of challenge in the methodology of developing complex systems models, and suggested additional areas for further study.

Breast cancer incidence and mortality in women under 50 years of age in Brazil

Many countries have reported an increase in breast cancer incidence in young women. The current study's objective was to explore breast cancer distribution in women less than 50 years of age in Brazil. A descriptive study on breast cancer incidence (selected cities) and mortality (Brazil and selected cities) in 2002-2004 was carried out, and the results were compared with those from other countries. The study also analyzed the trend in hospital morbidity and incidence rates for breast cancer. Porto Alegre (Rio Grande do Sul State) showed the highest incidence rates (17.9 and 165.5/100,000 in the 15-39 and 40-49-year age strata, respectively). Regarding mortality, Belo Horizonte (Minas Gerais State) showed the highest rate in the 15-39-year group and Porto Alegre in the 40-49-year group (2.8 and 25.5/100,000). Hospital admissions and incidence rates for breast cancer suggest a change in epidemiological distribution. The results reveal an epidemiological pattern of breast cancer in young Brazilian women with regional distribution characteristics.

Genetics for the general internist

The internist's goal is to determine a patient's disease risk and to implement preventative interventions. Genetic evaluation is a powerful risk assessment tool, and new interventions target previously untreatable genetic disorders. The purpose of this review is to educate the general internist about common genetic conditions affecting adult patients, with special emphasis on diagnoses with an effective intervention, including hereditary cancer syndromes and cardiovascular disorders. Basic tenets of genetic counseling, complex genetic disease, and management of adults with genetic diagnoses also are discussed.

Triple-negative breast cancers: an updated review on treatment options

Morphologic features of tumour cells have long been validated for the clinical classification of breast cancers and are regularly used as a "gold standard" to ascertain prognostic outcome in patients. Identification of molecular markers such as expression of the receptors for estrogen (er) and progesterone (pgr) and the human epidermal growth factor receptor 2 (her2) has played an important role in determining targets for the development of efficacious drugs for treatment and has also offered additional predictive value for the therapeutic assessment of patients with breast cancer. More recent technical advancements in identifying several cancer-related genes have provided further opportunities to identify specific subtypes of breast cancer. Among the subtypes, tumours with triple-negative cells are identified using specific staining procedures for basal markers such as cytokeratin 5 and 6 and the absence of er, pgr, and her2 expression. Patients with triple-negative breast cancers therefore have the disadvantage of not benefiting from currently available receptor-targeted systemic therapy. Optimal conditions for the therapeutic assessment of women with triple-negative breast tumours and for the management of their disease have yet to be validated in prospective investigations. The present review discusses the differences between triple-negative breast tumours and basal-like breast tumours and also the role of mutations in the BRCA genes. Attention is also paid to treatment options available to patients with triple-negative breast tumours.

Advances in breast cancer: pathways to personalized medicine

Breast cancer is a complex disease caused by the progressive accumulation of multiple gene mutations combined with epigenetic dysregulation of critical genes and protein pathways. There is substantial interindividual variability in both the age at diagnosis and phenotypic expression of the disease. With an estimated 1,152,161 new breast cancer cases diagnosed worldwide per year, cancer control efforts in the postgenome era should be focused at both population and individual levels to develop novel risk assessment and treatment strategies that will further reduce the morbidity and mortality associated with the disease. The discovery that mutations in the BRCA1 and BRCA2 genes increase the risk of breast and ovarian cancers has radically transformed our understanding of the genetic basis of breast cancer, leading to improved management of high-risk women. A better understanding of tumor host biology has led to improvements in the multidisciplinary management of breast cancer, and traditional pathologic evaluation is being complemented by more sophisticated genomic approaches. A number of genomic biomarkers have been developed for clinical use, and increasingly, pharmacogenetic end points are being incorporated into clinical trial design. For women diagnosed with breast cancer, prognostic or predictive information is most useful when coupled with targeted therapeutic approaches, very few of which exist for women with triple-negative breast cancer or those with tumors resistant to chemotherapy. The immediate challenge is to learn how to use the molecular characteristics of an individual and their tumor to improve detection and treatment, and ultimately to prevent the development of breast cancer. The five articles in this edition of CCR Focus highlight recent advances and future directions on the pathway to individualized approaches for the early detection, treatment, and prevention of breast cancer.

Breast cancer risk associated with BRCA1 and BRCA2 in diverse populations

Germline mutations in the BRCA1 or BRCA2 tumour-suppressor genes are strong predictors of breast and/or ovarian cancer development. The contribution of these mutations to breast cancer risk within any specific population is a function of both their prevalence and their penetrance. Mutation prevalence varies among ethnic groups and may be influenced by founder mutations. Penetrance can be influenced by mutation-specific phenotypes and the potential modifying effects of the patient's own genetic and environmental background. Although estimates of both mutation prevalence and mutation penetrance rates are inconsistent and occasionally controversial, understanding them is crucial for providing accurate risk information to each patient.

Primary fallopian tube malignancies in BRCA-positive women undergoing surgery for ovarian cancer risk reduction

PURPOSE

To review the frequency and location of malignancies detected after prophylactic salpingo-oophorectomy in women with BRCA mutations.

METHODS

Medical records and pathology findings were reviewed from BRCA-positive women undergoing prophylactic surgery for ovarian cancer risk reduction who underwent complete examination of the adnexa. Patients undergoing this procedure between January 1999 and January 2007 were identified.

RESULTS

From January 1999 to January 2007, 122 BRCA-positive patients underwent prophylactic surgery in the Division of Gynecologic Oncology at Brigham and Women's Hospital. The median age was 46.5 years (range, 33 to 76 years). Seven (5.7%) were found to have an early malignancy in the upper genital tract and all patients were age > or = 44 years at diagnosis. Of seven consecutive cancers culled between January 1999 and January 2007, all (100%) originated in the fimbrial or ampullary region of the tube; six had an early (intraepithelial) component. Two were associated with surface implants on the ovary and two required repeated sectioning to detect microscopic carcinomas in the fimbria.

CONCLUSION

The distal fallopian tube seems to be the dominant site of origin for early malignancies detected in approximately 6% of women undergoing ovarian cancer risk-reduction surgery. The greatest proportion of serous cancer risk in BRCA mutation-positive women should be assigned to the fimbria rather than the ovary, and future clinical and research protocols should employ thorough examination of the fimbria, including multiple sections from each tissue block, to maximize detection of early malignancies in this population.

Familial breast cancer: double heterozygosity for BRCA1 and BRCA2 mutations with differing phenotypes

The co-existence of mutations in the BRCA1 and BRCA2 genes is unusual, and to date almost all cases reported have had at least one of the Ashkenazi founder mutations. We report on a family in whom individuals are double heterozygotes for a mutation in BRCA1 and a novel splice site mutation in BRCA2. The phenotypes are discordant, where one sister has had multiple cancers in the BRCA spectrum, while the other is unaffected at 65 years of age. The utility of testing is discussed, and the completion of diagnostic testing despite the finding of a potentially causal mutation is validated.

Prevalence and predictors of BRCA1 and BRCA2 mutations in a population-based study of breast cancer in white and black American women ages 35 to 64 years

Although well studied in families at high-risk, the roles of mutations in the BRCA1 and BRCA2 genes are poorly understood in breast cancers in the general population, particularly in Black women and in age groups outside of the very young. We examined the prevalence and predictors of BRCA1 and BRCA2 mutations in 1,628 women with breast cancer and 674 women without breast cancer who participated in a multicenter population-based case-control study of Black and White women, 35 to 64 years of age. Among cases, 2.4% and 2.3% carried deleterious mutations in BRCA1 and BRCA2, respectively. BRCA1 mutations were significantly more common in White (2.9%) versus Black (1.4%) cases and in Jewish (10.2%) versus non-Jewish (2.0%) cases; BRCA2 mutations were slightly more frequent in Black (2.6%) versus White (2.1%) cases. Numerous familial and demographic factors were significantly associated with BRCA1 and, to a lesser extent, BRCA2 carrier status, when examined individually. In models considering all predictors together, early onset ages in cases and in relatives, family history of ovarian cancer, and Jewish ancestry remained strongly and significantly predictive of BRCA1 carrier status, whereas BRCA2 predictors were fewer and more modest in magnitude. Both the combinations of predictors and effect sizes varied across racial/ethnic and age groups. These results provide first-time prevalence estimates for BRCA1/BRCA2 in breast cancer cases among understudied racial and age groups and show key predictors of mutation carrier status for both White and Black women and women of a wide age spectrum with breast cancer in the general population.

Population attributes affecting the prevalence of BRCA mutation carriers in epithelial ovarian cancer cases in israel

OBJECTIVE

The objective was to evaluate the prevalence of BRCA1/2 mutations in selected categories of ovarian cancer patients in Israel.

METHODS

Blood samples and specimens of ovarian tumors were obtained in the course of a national case control study of women with ovarian cancer in Israel. Eight hundred ninety-six patients with epithelial ovarian cancer, 40 cases with nonepithelial ovarian cancer, and 68 with primary peritoneal cancer were tested for the BRCA mutations. Analysis of the three common BRCA mutations in Israel (185delAG, 5382insC in BRCA1, and 6174delT in BRCA2) was done using a multiplex polymerase chain reaction assay. A multivariate logistic regression model was used to assess the association of mutation carrier status and other factors (age, origin, family history, and clinical variables).

RESULTS

Of the 779 invasive epithelial ovarian cancer cases, 29.4% were mutation carriers. The prevalence of the mutations was higher among women below age 60 and in more advanced cases. The prevalence was low in mucinous tumors. There was almost a twofold excess of mutations among women with positive family history (45.7%), but still 26.5% of the family history negative cases were carriers. As expected, we found a higher rate of mutation carriers among the Ashkenazi group (34.2%) and 55% among Ashkenazi women with positive family history. No subjects born in North Africa were mutation positive.

CONCLUSION

BRCA mutations are strongly associated with ovarian cancer and they are present in variable rates in distinct age, ethnic, and histopathologic categories.

BRCA1 and BRCA2 germline mutations in Sardinian breast cancer families and their implications for genetic counseling

BACKGROUND

The Sardinian population is genetically homogeneous and could be useful in understanding better the genetics of a complex disease like breast cancer (BC).

PATIENTS AND METHODS

Using a screening assay based on a combination of single-strand conformation polymorphism, denaturing high-performance liquid chromatography and sequence analysis, 47 Sardinian families with three or more BC cases were screened for germline mutations in BRCA1 and BRCA2 genes.

RESULTS

Three BRCA1/2 germline sequence variants were identified. While BRCA2-Ile3412Val is a missense variant with unknown functional significance, BRCA2-8765delAG and BRCA1-Lys505ter are two deleterious mutations (due to their predicted effects on protein truncation), which were found in seven families (15%). BRCA2-8765delAG was found in six of eight (75%) BRCA1/2-positive families and seven of 501 (1.4%) unselected and consecutively collected BC patients. Prevalence of BRCA1/2 mutations in BC families was significantly correlated with the total number of female BCs (P <0.01) and increased by the presence of (i) at least one case of ovarian or male BC, or (ii) three generations affected, or (iii) bilateral BC.

CONCLUSIONS

Identification of such features should address BC patients and their families to genetic counseling and BRCA1/2 mutational analysis. In addition, this is the first report of a detailed BRCA1/2 mutation screening in Sardinia, having immediate implications for the clinical management of BC families.

Clinical considerations in the management of individuals at risk for hereditary breast and ovarian cancer

BACKGROUND

Hereditary predisposition to breast and ovarian cancer, most commonly due to germline mutations in BRCA1 and BRCA2, has been recognized for many years. The optimal clinical management of individuals with such a predisposition is not yet completely defined.

METHODS

The current literature regarding the clinical management of individuals at risk for hereditary breast and ovarian cancer was reviewed.

RESULTS

Women with germline BRCA1 or BRCA2 mutations are at substantially increased risk for breast and ovarian cancer, although the risks may not be as high as originally reported. Current surveillance options are restricted in their effectiveness by both host and tumor factors as well as limitations of the techniques. Surgical prevention options, while effective, may be complicated by physical or psychological morbidity. Nonsurgical prevention options are under development.

CONCLUSIONS

The ability to define women as being at hereditary risk for breast and ovarian cancer facilitates the use of specialized surveillance and prevention strategies. Genetic testing, which plays a role in defining risk, requires careful pre- and post-test counseling to discuss the limitations of testing itself and available management strategies.

Pretest prediction of BRCA1 or BRCA2 mutation by risk counselors and the computer model BRCAPRO

BACKGROUND

Because BRCA gene mutation testing is costly, occasionally uninformative, and frequently associated with ethical and legal issues, careful patient selection is required prior to testing. Estimation of BRCA gene mutation probability is an important component of pretest counseling, but the accuracy of these estimates is currently unknown. We measured the performance of eight cancer risk counselors and of a computer model, BRCAPRO, at identifying families likely to carry a BRCA gene mutation.

METHODS

Eight cancer risk counselors and the computer model BRCAPRO estimated BRCA gene mutation probabilities for 148 pedigrees selected from an initial sample of 272 pedigrees. The final sample was limited to pedigrees with a proband affected by breast or ovarian cancer and BRCA1 and BRCA2 gene sequencing results unequivocally reported as negative or positive for a deleterious mutation. Sensitivity, specificity, negative predictive value, positive predictive value, and areas under receiver operator characteristics (ROC) curves were calculated for each risk counselor and for BRCAPRO. All statistical tests were two sided.

RESULTS

Using a greater-than-10% BRCA gene mutation probability threshold, the median sensitivity for identifying mutation carriers was 94% (range = 81% to 98%) for the eight risk counselors and 92% (range = 91% to 92%) for BRCAPRO. Median specificity at this threshold was 16% (range = 6% to 34%) for the risk counselors and 32% (range = 30% to 34%) for BRCAPRO (P =.04). Median area under the ROC curves was 0.671 for the risk counselors (range = 0.620 to 0.717) and 0.712 (range = 0.706 to 0.720) for BRCAPRO (P =.04). There was a slight, but not statistically significant, improvement in all counselor performance measures when BRCAPRO-assigned gene mutation probability information was included with the pedigrees.

CONCLUSIONS

Sensitivity for identifying BRCA gene mutation carriers is similar for experienced risk counselors and the computer model BRCAPRO. Because the computer model consistently demonstrated superior specificity, overall discrimination between BRCA gene mutation carriers and BRCA gene mutation noncarriers was slightly better for BRCAPRO.

Mutational analyses of BRCA1 and BRCA2 in Ashkenazi and non-Ashkenazi Jewish women with familial breast and ovarian cancer

In Ashkenazi (East European) Jews, three predominant mutations in BRCA1 (185delAG and 5382insC) and BRCA2 (6174delT) account for the majority of germline mutations in high-risk breast and/or ovarian cancer families. Among non-Ashkenazi Jews, the 185delAG, Tyr978Ter, and a handful of "private" mutations have been reported anecdotally within both genes. In this study we attempted to determine the spectrum of BRCA1 and BRCA2 mutations in high-risk Jewish individuals, non-carriers of any of the predominant Jewish mutations. We employed multiplex PCR and denaturing gradient gel electrophoresis (DGGE) analysis for BRCA2, and combined denaturing high performance liquid chromatography (DHPLC) and protein truncation test (PTT) for BRCA1, complemented by DNA sequencing. We screened 47 high-risk Jewish individuals, 26 Ashkenazis, and 21 non-Ashkenazis. Overall, 13 sequence alterations in BRCA1 and eight in BRCA2 were detected: nine neutral polymorphisms and 12 missense mutations, including five novel ones. The novel missense mutations did not co-segregate with disease in BRCA1 and were detected at rates of 6.25% to 52.5% in the general population for BRCA2. Our findings suggest that except for the predominant mutations in BRCA1 and BRCA2 in Jewish individuals, there are only a handful of pathogenic mutations within these genes. It may imply novel genes may underlie inherited susceptibility to breast/ovarian cancer in Jewish individuals.