Kenneth Offit

Sequence analysis of BRCA1 and BRCA2: correlation of mutations with family history and ovarian cancer risk.

PURPOSE Previous studies of mutations in BRCA1 or BRCA2 have used detection methods that may underestimate the actual frequency of mutations and have analyzed women using heterogeneous criteria for risk of hereditary cancer. PATIENTS AND METHODS A total of 238 women with breast cancer before age 50 or ovarian cancer at any age and at least one first- or second-degree relative with either diagnosis underwent sequence analysis of BRCA1 followed by analysis of BRCA2 (except for 27 women who declined analysis of BRCA2 after a deleterious mutation was discovered in BRCA1). Results were correlated with personal and family history of malignancy. RESULTS Deleterious mutations were identified in 94 (39%) women, including 59 of 117 (50%) from families with ovarian cancer and 35 of 121 (29%) from families without ovarian cancer. Mutations were identified in 14 of 70 (20%) women with just one other relative who developed breast cancer before age 50. In women with breast cancer, mutations in BRCA1 and BRCA2 were associated with a 10-fold increased risk of subsequent ovarian carcinoma (P = .005). CONCLUSION Because mutations in BRCA1 and BRCA2 in women with breast cancer are associated with an increased risk of ovarian cancer, analysis of these genes should be considered for women diagnosed with breast cancer who have a high probability of carrying a mutation according to the statistical model developed with these data.

Outcome of Preventive Surgery and Screening for Breast and Ovarian Cancer in BRCA Mutation Carriers

PURPOSE To prospectively determine the impact of genetic counseling and testing on risk-reduction strategies and cancer incidence in a cohort of individuals at hereditary risk for breast and ovarian cancer. PATIENTS AND METHODS Two hundred fifty-one individuals with BRCA mutations were identified at a single comprehensive cancer center from May 1, 1995, through October 31, 2000. Uniform recommendations regarding screening and preventive surgery were provided in the context of genetic counseling. Patients were followed for a mean of 24.8 months (range, 1.6 to 66.0 months) using standardized questionnaires, chart reviews, and contact with primary physicians. RESULTS Frequency of cancer surveillance by physical examinations and imaging studies increased after genetic counseling and testing. Twenty-one breast, ovarian, primary peritoneal, or fallopian tube cancers were detected after receipt of genetic test results. Among 29 individuals choosing risk-reducing mastectomy after testing, two were found to have occult intraductal breast cancers. Among 90 individuals who underwent risk-reducing salpingo-oophorectomy, one early-stage ovarian neoplasm and one early-stage fallopian tube neoplasm were found. Radiographic or tumor marker-based screening detected six breast cancers, five of which were stage 0/I, one early-stage primary peritoneal cancer, and three stage I or II ovarian cancers. Six additional breast cancers were detected by physical examination between radiographic screening intervals; four of these six tumors were stage I. No stage III or stage IV malignancies were detected after genetic testing. CONCLUSION This study provides prospective evidence that genetic counseling and testing increased surveillance and led to risk-reducing operations, which resulted in diagnosis of early-stage tumors in patients with BRCA1 and BRCA2 mutations.

Risk-reducing salpingo-oophorectomy for the prevention of BRCA1- and BRCA2-associated breast and gynecologic cancer: a multicenter, prospective study.

PURPOSE Risk-reducing salpingo-oophorectomy (RRSO) has been widely adopted as a key component of breast and gynecologic cancer risk-reduction for women with BRCA1 and BRCA2 mutations. Despite 17% to 39% of all BRCA mutation carriers having a mutation in BRCA2, no prospective study to date has evaluated the efficacy of RRSO for the prevention of breast and BRCA-associated gynecologic (ovarian, fallopian tube or primary peritoneal) cancer when BRCA2 mutation carriers are analyzed separately from BRCA1 mutation carriers. PATIENTS AND METHODS A total of 1,079 women 30 years of age and older with ovaries in situ and a deleterious BRCA1 or BRCA2 mutation were enrolled onto prospective follow-up studies at one of 11 centers from November 1, 1994 to December 1, 2004. Women self-selected RRSO or observation. Follow-up information through November 30, 2005, was collected by questionnaire and medical record review. The effect of RRSO on time to diagnosis of breast or BRCA-associated gynecologic cancer was analyzed using a Cox proportional-hazards model. RESULTS During 3-year follow-up, RRSO was associated with an 85% reduction in BRCA1-associated gynecologic cancer risk (hazard ratio [HR] = 0.15; 95% CI, 0.04 to 0.56) and a 72% reduction in BRCA2-associated breast cancer risk (HR = 0.28; 95% CI, 0.08 to 0.92). While protection against BRCA1-associated breast cancer (HR = 0.61; 95% CI, 0.30 to 1.22) and BRCA2-associated gynecologic cancer (HR = 0.00; 95% CI, not estimable) was suggested, neither effect reached statistical significance. CONCLUSION The protection conferred by RRSO against breast and gynecologic cancers may differ between carriers of BRCA1 and BRCA2 mutations. Further studies evaluating the efficacy of risk-reduction strategies in BRCA mutation carriers should stratify by the specific gene mutated.

Germline mutations in BAP1 predispose to melanocytic tumors

Common acquired melanocytic nevi are benign neoplasms that are composed of small, uniform melanocytes and are typically present as flat or slightly elevated pigmented lesions on the skin. We describe two families with a new autosomal dominant syndrome characterized by multiple, skin-colored, elevated melanocytic tumors. In contrast to common acquired nevi, the melanocytic neoplasms in affected family members ranged histopathologically from epithelioid nevi to atypical melanocytic proliferations that showed overlapping features with melanoma. Some affected individuals developed uveal or cutaneous melanomas. Segregating with this phenotype, we found inactivating germline mutations of BAP1, which encodes a ubiquitin carboxy-terminal hydrolase. The majority of melanocytic neoplasms lost the remaining wild-type allele of BAP1 by various somatic alterations. In addition, we found BAP1 mutations in a subset of sporadic melanocytic neoplasms showing histological similarities to the familial tumors. These findings suggest that loss of BAP1 is associated with a clinically and morphologically distinct type of melanocytic neoplasm.

Breast Cancer Risk Following Bilateral Oophorectomy in BRCA1 and BRCA2 Mutation Carriers: An International Case-Control Study

PURPOSE The purpose of this study was to estimate the extent of protection offered against breast cancer by prophylactic oophorectomy in carriers of BRCA1 or BRCA2 mutations and to determine to what extent risk reduction varies with age at oophorectomy, age at diagnosis, and time elapsed since surgery. PATIENTS AND METHODS We analyzed 1,439 patients with breast cancer and 1,866 matched controls derived from a registry of BRCA1 and BRCA2 carriers. We estimated odds ratios (ORs) of breast cancer for having had a bilateral oophorectomy, using conditional logistic regression, matched for parity and for oral contraceptive use. RESULTS A previous history of oophorectomy was associated with a significant reduction in breast cancer risk of 56% for BRCA1 carriers (OR = 0.44; 95% CI, 0.29 to 0.66) and of 46% for BRCA2 carriers (OR = 0.57; 95% CI, 0.28 to 1.15). The risk reduction was greater if the oophorectomy was performed before age 40 (OR = 0.36; 95% CI, 0.20 to 0.64 for BRCA1 carriers) than after age 40 (OR = 0.53; 95% CI, 0.30 to 0.91). The protective effect was evident for 15 years post-oophorectomy (OR = 0.39; 95% CI, 0.26 to 0.57). CONCLUSION Oophorectomy is an effective means of reducing the risk of breast cancer in carriers of BRCA1 mutations. The data suggest oophorectomy is protective in BRCA2 carriers as well, but needs to be confirmed in other studies.

Hereditary Cancer Predisposition Syndromes

Cancer genetics is increasingly becoming integrated into the practice of modern medical oncology. The ability to distinguish a growing proportion of the 5% to 10% of all cancers that develop in individuals who have inherited a genetic mutation conferring heightened susceptibility to specific cancers may permit targeted efforts in cancer surveillance and prevention. While these individuals comprise a small proportion of the overall burden of cancer, strategies successful in reducing their remarkable cancer risks may be generalizable to the broader population. In this review, we highlight the most common hereditary cancer syndromes, most attributable to genes inherited in an autosomal dominant manner with incomplete penetrance, and a number of rare syndromes in which particular progress has been made. The prevalence, penetrance, tumor spectrum, and underlying genetic defects are discussed and summarized in a large table in which a more comprehensive enumeration of syndromes is provided.

BRCA-associated breast cancer in young women.

PURPOSE To delineate the clinical characteristics and outcomes of breast cancer that arises in the setting of a germline BRCA mutation and to compare BRCA-associated breast cancers (BABC) with those that arise in women without mutations. PATIENTS AND METHODS We reviewed the clinical records of 91 Ashkenazi Jewish women ascertained during studies of the genetics of early-onset breast cancer. All women underwent testing for the BRCA1 mutations 185delAG and 5382insC. After the discovery of BRCA2, 79 women were also tested for the BRCA2 mutation 6174delT. RESULTS Mutations were identified in 30 women (33%). BABC were less likely to present with stage I disease than cases in women without mutations (27% v 46%), more likely to have axillary nodal involvement (54% v46%), and more likely to have extensive axillary involvement (25% v 17%). These differences were not statistically significant. BABC were significantly more likely to be histologic grade III (100% v 59%, P=.04) and to be estrogen receptor-negative (70% v 34%, P=.04). In the entire cohort, there were no significant differences between BABC and non-BRCA-associated cancers in 5-year relapse-free survival (65% v 69%, P=not significant [NS]), 5-year event-free survival (57% v 68%, P=NS), or 5-year overall survival. However, among cases diagnosed within 2 years of study entry, there was a trend toward shorter event-free survival in BRCA heterozygotes, but not relapse-free survival. Women with germline BRCA mutations were significantly more likely to develop contralateral breast cancer at 5 years (31% v 4%, P=.0007). CONCLUSION BABC present with adverse clinical and histopathologic features when compared with cases not associated with BRCA mutations. However, the prognosis of BABC appears to be similar to that of nonassociated cancer. Further studies of incident cases are necessary to define the independent prognostic significance of germline BRCA mutations.

Genome-wide association study provides evidence for a breast cancer risk locus at 6q22.33

We performed a three-phase genome-wide association study (GWAS) using cases and controls from a genetically isolated population, Ashkenazi Jews (AJ), to identify loci associated with breast cancer risk. In the first phase, we compared allele frequencies of 150,080 SNPs in 249 high-risk, BRCA1/2 mutation-negative AJ familial cases and 299 cancer-free AJ controls using χ2 and the Cochran–Armitage trend tests. In the second phase, we genotyped 343 SNPs from 123 regions most significantly associated from stage 1, including 4 SNPs from the FGFR2 region, in 950 consecutive AJ breast cancer cases and 979 age-matched AJ controls. We replicated major associations in a third independent set of 243 AJ cases and 187 controls. We obtained a significant allele P value of association with AJ breast cancer in the FGFR2 region (P = 1.5 × 10−5, odds ratio (OR) 1.26, 95% confidence interval (CI) 1.13–1.40 at rs1078806 for all phases combined). In addition, we found a risk locus in a region of chromosome 6q22.33 (P = 2.9 × 10−8, OR 1.41, 95% CI 1.25–1.59 at rs2180341). Using several SNPs at each implicated locus, we were able to verify associations and impute haplotypes. The major haplotype at the 6q22.33 locus conferred protection from disease, whereas the minor haplotype conferred risk. Candidate genes in the 6q22.33 region include ECHDC1, which encodes a protein involved in mitochondrial fatty acid oxidation, and also RNF146, which encodes a ubiquitin protein ligase, both known pathways in breast cancer pathogenesis.

A germline JAK2 SNP is associated with predisposition to the development of JAK2V617F-positive myeloproliferative neoplasms

Polycythemia vera, essential thrombocythemia and primary myelofibrosis are myeloproliferative neoplasms (MPN) characterized by multilineage clonal hematopoiesis. Given that the identical somatic activating mutation in the JAK2 tyrosine kinase gene (JAK2V617F) is observed in most individuals with polycythemia vera, essential thrombocythemia and primary myelofibrosis, there likely are additional genetic events that contribute to the pathogenesis of these phenotypically distinct disorders. Moreover, family members of individuals with MPN are at higher risk for the development of MPN, consistent with the existence of MPN predisposition loci. We hypothesized that germline variation contributes to MPN predisposition and phenotypic pleiotropy. Genome-wide analysis identified an allele in the JAK2 locus (rs10974944) that predisposes to the development of JAK2V617F-positive MPN, as well as three previously unknown MPN modifier loci. We found that JAK2V617F is preferentially acquired in cis with the predisposition allele. These data suggest that germline variation is an important contributor to MPN phenotype and predisposition.

MDM2 SNP309 Accelerates Tumor Formation in a Gender-Specific and Hormone-Dependent Manner

The importance of the p53 stress response pathway in the suppression of tumor formation is well documented. In a previous report, a single nucleotide polymorphism (SNP309 T/G) was found in the promoter of the MDM2 gene resulting in higher levels of MDM2 RNA and protein and, consequently, in the attenuation of the p53 pathway both in vitro and in vivo. As the SNP309 locus is found in a region of the MDM2 promoter, which is regulated by hormonal signaling pathways, and the G-allele of SNP309 increases the affinity of a well-described cotranscriptional activator of nuclear hormone receptors (i.e., Sp1), the hypothesis that the SNP309 locus could alter the effects of hormones on tumorigenesis was tested in vivo in humans. Data obtained from patients with three different sporadic cancers, from four independent case studies, support this hypothesis, providing an example for the genetic basis of gender differences in cancer and showing that the genotype at a specific locus can affect how hormones, like estrogen, affect tumorigenesis in humans.