Kathleen R. Blazer

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 ofHispanicorigin, with a personal or family history of breast and/orovarian cancer, presented for genetic cancer risk assessment, were enrolled in an Institutional Review Board–approved registry and underwent BRCA testing. Haplotype analyseswere 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 ofadditional 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 seenalmost 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 wasprevalent (3.6%) in this clinic-based cohort of predominantly Mexican descent, and shared the Ashkenazi Jewishfounder haplotype.

Genetics, Genomics and Cancer Risk Assessment: State of the art and future directions in the era of personalized medicine

Scientific and technologic advances are revolutionizing our approach to genetic cancer risk assessment, cancer screening and prevention, and targeted therapy, fulfilling the promise of personalized medicine. In this monograph, we review the evolution of scientific discovery in cancer genetics and genomics, and describe current approaches, benefits, and barriers to the translation of this information to the practice of preventive medicine. Summaries of known hereditary cancer syndromes and highly penetrant genes are provided and contrasted with recently discovered genomic variants associated with modest increases in cancer risk. We describe the scope of knowledge, tools, and expertise required for the translation of complex genetic and genomic test information into clinical practice. The challenges of genomic counseling include the need for genetics and genomics professional education and multidisciplinary team training, the need for evidence‐based information regarding the clinical utility of testing for genomic variants, the potential dangers posed by premature marketing of first‐generation genomic profiles, and the need for new clinical models to improve access to and responsible communication of complex disease risk information. We conclude that given the experiences and lessons learned in the genetics era, the multidisciplinary model of genetic cancer risk assessment and management will serve as a solid foundation to support the integration of personalized genomic information into the practice of cancer medicine. CA Cancer J Clin 2011.

Reflex Immunohistochemistry and Microsatellite Instability Testing of Colorectal Tumors for Lynch Syndrome Among US Cancer Programs and Follow-Up of Abnormal Results

PURPOSE Immunohistochemistry (IHC) for MLH1, MSH2, MSH6, and PMS2 protein expression and microsatellite instability (MSI) are well-established tools to screen for Lynch syndrome (LS). Although many cancer centers have adopted these tools as reflex LS screening after a colorectal cancer diagnosis, the standard of care has not been established, and no formal studies have described this practice in the United States. The purpose of this study was to describe prevalent practices regarding IHC/MSI reflex testing for LS in the United States and the subsequent follow-up of abnormal results. MATERIALS AND METHODS A 12-item survey was developed after interdisciplinary expert input. A letter of invitation, survey, and online-survey option were sent to a contact at each cancer program. A modified Dillman strategy was used to maximize the response rate. The sample included 39 National Cancer Institute-designated Comprehensive Cancer Centers (NCI-CCCs), 50 randomly selected American College of Surgeons-accredited Community Hospital Comprehensive Cancer Programs (COMPs), and 50 Community Hospital Cancer Programs (CHCPs). RESULTS The overall response rate was 50%. Seventy-one percent of NCI-CCCs, 36% of COMPs, and 15% of CHCPs were conducting reflex IHC/MSI for LS; 48% of the programs used IHC, 14% of the programs used MSI, and 38% of the programs used both IHC and MSI. One program used a presurgical information packet, four programs offered an opt-out option, and none of the programs required written consent. CONCLUSION Although most NCI-CCCs use reflex IHC/MSI to screen for LS, this practice is not well-adopted by community hospitals. These findings may indicate an emerging standard of care and diffusion from NCI-CCC to community cancer programs. Our findings also described an important trend away from requiring written patient consent for screening.

Evidence for Common Ancestral Origin of a Recurring BRCA1 Genomic Rearrangement Identified in High-Risk Hispanic Families

Background: Large rearrangements account for 8% to 15% of deleterious BRCA mutations, although none have been characterized previously in individuals of Mexican ancestry. Methods: DNA from 106 Hispanic patients without an identifiable BRCA mutation by exonic sequence analysis was subjected to multiplexed quantitative differential PCR. One case of Native American and African American ancestry was identified via multiplex ligation-dependent probe amplification. Long-range PCR was used to confirm deletion events and to clone and sequence genomic breakpoints. Splicing patterns were derived by sequencing cDNA from reverse transcription-PCR of lymphoblastoid cell line RNA. Haplotype analysis was conducted for recurrent mutations. Results: The same deletion of BRCA1 exons 9 through 12 was identified in five unrelated families. Long-range PCR and sequencing indicated a deletion event of 14.7 kb. A 3-primer PCR assay was designed based on the deletion breakpoints, identified within an AluSp element in intron 8 and an AluSx element in intron 12. Haplotype analysis confirmed common ancestry. Analysis of cDNA showed direct splicing of exons 8 to 13, resulting in a frameshift mutation and predicted truncation of the BRCA1 protein. Conclusions: We identified and characterized a novel large BRCA1 deletion in five unrelated families—four of Mexican ancestry and one of African and Native American ancestry, suggesting the possibility of founder effect of Amerindian or Mestizo origin. This BRCA1 rearrangement was detected in 3.8% (4 of 106) of BRCA sequence-negative Hispanic families. An assay for this mutation should be considered for sequence-negative high-risk Hispanic patients. (Cancer Epidemiol Biomarkers Prev 2007;16(8):1615–20)

Clinical Application of Multigene Panels: Challenges of Next-Generation Counseling and Cancer Risk Management

Background Multigene panels can be a cost- and time-effective alternative to sequentially testing multiple genes, especially with a mixed family cancer phenotype. However, moving beyond our single-gene testing paradigm has unveiled many new challenges to the clinician. The purpose of this article is to familiarize the reader with some of the challenges, as well as potential opportunities, of expanded hereditary cancer panel testing. Methods We include results from 348 commercial multigene panel tests ordered from January 1, 2014, through October 1, 2014, by clinicians associated with the City of Hope’s Clinical Cancer Genetics Community of Practice. We also discuss specific challenging cases that arose during this period involving abnormalities in the genes: CDH1, TP53, PMS2, PALB2, CHEK2, NBN, and RAD51C. Results If historically high risk genes only were included in the panels (BRCA1, BRCA2, MSH6, PMS2, TP53, APC, CDH1), the results would have been positive only 6.2% of the time, instead of 17%. Results returned with variants of uncertain significance (VUS) 42% of the time. Conclusion These figures and cases stress the importance of adequate pre-test counseling in anticipation of higher percentages of positive, VUS, unexpected, and ambiguous test results. Test result ambiguity can be limited by the use of phenotype-specific panels; if found, multiple resources (the literature, reference laboratory, colleagues, national experts, and research efforts) can be accessed to better clarify counseling and management for the patient and family. For pathogenic variants in low and moderate risk genes, empiric risk modeling based on the patient’s personal and family history of cancer may supersede gene-specific risk. Commercial laboratory and patient contributions to public databases and research efforts will be needed to better classify variants and reduce clinical ambiguity of multigene panels.

Social‐cognitive aspects of underserved Latinas preparing to undergo genetic cancer risk assessment for hereditary breast and ovarian cancer

Objectives: As Latinos are a growing ethnic group in the United States, it is important to understand the socio‐cultural factors that may be associated with cancer screening and prevention in this population. The socio‐cultural factors that may affect preparedness to undergo genetic cancer risk assessment (GCRA) deserve particular attention. The pre‐GCRA period can provide insight into variables that may influence how medically underserved Latinas, with limited health resources and access, understand hereditary cancer information and subsequently implement cancer risk management recommendations. This study explores social, cognitive and cultural variables in Latinas prior to undergoing GCRA.

Reduced mammographic density with use of a gonadotropin-releasing hormone agonist - Based chemoprevention regimen in BRCA1 carriers

Purpose: Women with a BRCA1 mutation (BRCA1mut) need risk reduction options beyond mastectomy and oophorectomy. We evaluated the efficacy, safety, and tolerability of hormonal chemoprevention with a gonadotropin-releasing hormone agonist (GnRHA) with low-dose add-back steroids in BRCA1mut carriers. Experimental Design: The 12-month open label clinical trial used the GnRHA deslorelin, ultra-low-dose estradiol (E2), and replacement testosterone, administered via daily intranasal spray in premenopausal women with a BRCA1mut, and intermittent oral medroxyprogesterone acetate. The end points included mammographic percent density, bone mineral density, endometrial hyperplasia, symptom inventory, and quality of life (Medical Outcomes SF-36 survey). Results: Six of eight BRCA1mut women (mean age, 30.3 years; range, 25-36 years) completed the study. Mammographic percent density was significantly reduced at 12 months (median absolute mammographic percent density decrease, 8.3%; P = 0.043), representing a 29.2% median reduction in mammographic percent density. Bone mineral density remained within reference limits for all participants; there were no cases of atypical endometrial hyperplasia and menses resumed within a median of 67 days (range, 35-110 days) after last drug treatment day. The treatment was well tolerated; hypoestrogenic side effects were minimal and transient; and there were no significant changes in quality of life. Conclusions: The GnRHA deslorelin, with low-dose add-back steroids, was well tolerated and significantly decreased mammographic percent density in BRCA1mut carriers. This regimen may reduce breast cancer risk and improve the usefulness of mammographic surveillance by reducing density. This is the first demonstration, to our knowledge, of a direct reduction of mammographic densities in young BRCA1mut carriers.

Significant Clinical Impact of Recurrent BRCA1 and BRCA2 Mutations in Mexico

Frequent recurrent mutations in the breast and ovarian cancer susceptibility (BRCA) genes BRCA1 and BRCA2 among Hispanics, including a large rearrangement Mexican founder mutation (BRCA1 exon 9‐12 deletion [ex9‐12del]), suggest that an ancestry‐informed BRCA‐testing strategy could reduce disparities and promote cancer prevention by enabling economic screening for hereditary breast and ovarian cancer in Mexico.

Concerns of women presenting to a comprehensive cancer centre for genetic cancer risk assessment

About 5-10% of breast and ovarian cancers are the result of an autosomal dominant inherited predisposition, with a significant portion resulting from a germline mutation in the highly penetrant BRCA1 or BRCA2 genes.1 The risk for breast cancer in women who carry a BRCA mutation is estimated to be 33-50% by the age of 50 and 56-85% by the age of 70,1–4 and the risk of a second breast cancer may be as high as 60% over a womans lifetime. The risk of ovarian cancer ranges from about 10-50%. Women are increasingly presenting for genetic cancer risk assessment (GCRA) services, wherein genetic testing and empirical data may be used to predict breast and ovarian cancer risk. Risk management options ranging from close surveillance to chemoprevention to prophylactic surgery are discussed as part of the GCRA consultation. While there is clearly a potential to benefit carefully selected and counselled subjects and family members who choose to undergo predisposition genetic testing,5,6 numerous barriers exist to the appropriate application of this emerging technology.7,8 Attention to the psychological implications of hereditary cancer including passing on a disease associated gene to ones children (transmission guilt) or alterations in family relationships are inherent in the counselling process. It is essential to understand the needs, beliefs, and values of women who seek GCRA services.9 The purpose of this pilot study was to ascertain the motivations and concerns of women presenting to a comprehensive cancer centre for GCRA in order to understand their needs better. The study findings provided valuable insights into womens concerns and served as the basis for an ongoing comprehensive evaluation of needs in a larger cohort. ### Eligibility The study was approved by both the City of Hopes (COH) clinical protocol review and monitoring committee and institutional review …

Outcomes from intensive training in genetic cancer risk counseling for clinicians

Purpose: Genetic cancer risk assessment is an emerging interdisciplinary practice that requires knowledge of genetics and oncology and specialized patient and family counseling skills. There is a growing need for cancer risk assessment practitioners, but most clinicians have inadequate cross-disciplinary training. An interdisciplinary course was developed to promote practitioner-level competency in cancer risk assessment to community-based clinicians.Methods: Participants were competitively selected from a pool of board-certified/eligible genetic counseling, masters-trained advanced practice nursing and physician applicants. Preference was given to clinicians with strong institutional backing practicing in underserved regions. The Continuing Medical Education/Continuing Education Unit-accredited course included didactic lectures, workshops, counseling practicum, and case conferences. Pre- and postcourse knowledge tests measured cancer genetics knowledge. Six month and one-year postcourse practice outcome surveys measured the impact of the program on professional self-efficacy and continued professional development.Results/Conclusions: Forty clinicians completed the course (23 genetic counselors, 14 nurses, and three physicians). There was a significant overall increase of 22.6% in postcourse knowledge scores (P < 0.001). Thirty-five (88%) completed prescribed practice development activities. Of 29 respondents to 1-year postcourse survey, 76% reported increased professional self-efficacy; 66% reported increase in number of patients seen, and virtually all indicated interest in additional training. Outcomes demonstrate the value and efficacy of interdisciplinary training in genetic cancer risk assessment targeted to motivated community-based clinicians. Courses such as this can help address the need for competent cancer risk assessment services in communities outside the academic health center.