Kristen M. Shannon

Cowden Syndrome and the PTEN Hamartoma Tumor Syndrome: Systematic Review and Revised Diagnostic Criteria

BACKGROUND PTEN hamartoma tumor syndrome (PHTS) refers to a spectrum of disorders caused by mutations in the phosphatase and tensin homolog (PTEN) gene. Diagnostic criteria for Cowden syndrome, the principal PTEN-related disorder, were first established in 1996 before the identification of the PTEN gene and the ability to molecularly confirm a clinical diagnosis. These consortium criteria were based on clinical experience and case reports in the existing literature, with their inherent selection biases. Although it was initially reported that approximately 80% of patients with Cowden syndrome had an identifiable germline PTEN mutation, more recent work has shown these diagnostic criteria to be far less specific. In addition, increasing evidence has documented the association of a broader spectrum of clinical features with PTEN mutations. Our goal was to develop revised, evidence-based diagnostic criteria and to include features of the broader spectrum of PTEN-related clinical syndromes. METHODS We performed a systematic search and review of the medical literature related to clinical features reported in individuals with a PTEN mutation and/or a related clinical diagnosis. RESULTS We found no sufficient evidence to support inclusion of benign breast disease, uterine fibroids, or genitourinary malformations as diagnostic criteria. There was evidence to include autism spectrum disorders, colon cancer, esophageal glycogenic acanthosis, penile macules, renal cell carcinoma, testicular lipomatosis, and vascular anomalies. CONCLUSIONS We propose revised, evidence-based criteria covering the spectrum of PTEN-related clinical disorders. Additional research on clinical features associated with PTEN mutations is warranted.

Clinical Actionability of Multigene Panel Testing for Hereditary Breast and Ovarian Cancer Risk Assessment

IMPORTANCE The practice of genetic testing for hereditary breast and/or ovarian cancer (HBOC) is rapidly evolving owing to the recent introduction of multigene panels. While these tests may identify 40% to 50% more individuals with hereditary cancer gene mutations than does testing for BRCA1/2 alone, whether finding such mutations will alter clinical management is unknown. OBJECTIVE To define the potential clinical effect of multigene panel testing for HBOC in a clinically representative cohort. DESIGN, SETTING, AND PARTICIPANTS Observational study of patients seen between 2001 and 2014 in 3 large academic medical centers. We prospectively enrolled 1046 individuals who were appropriate candidates for HBOC evaluation and who lacked BRCA1/2 mutations. INTERVENTIONS We carried out multigene panel testing on all participants, then determined the clinical actionability, if any, of finding non-BRCA1/2 mutations in these and additional comparable individuals. MAIN OUTCOMES AND MEASURES We evaluated the likelihood of (1) a posttest management change and (2) an indication for additional familial testing, considering gene-specific consensus management guidelines, gene-associated cancer risks, and personal and family history. RESULTS Among 1046 study participants, 40 BRCA1/2-negative patients (3.8%; 95% CI, 2.8%-5.2%) harbored deleterious mutations, most commonly in moderate-risk breast and ovarian cancer genes (CHEK2, ATM, and PALB2) and Lynch syndrome genes. Among these and an additional 23 mutation-positive individuals enrolled from our clinics, most of the mutations (92%) were consistent with the spectrum of cancer(s) observed in the patient or family, suggesting that these results are clinically significant. Among all 63 mutation-positive patients, additional disease-specific screening and/or prevention measures beyond those based on personal and family history alone would be considered for most (33 [52%] of 63; 95% CI, 40.3%-64.2%). Furthermore, additional familial testing would be considered for those with first-degree relatives (42 [72%] of 58; 95% CI, 59.8%-82.2%) based on potential management changes for mutation-positive relatives. This clinical effect was not restricted to a few of the tested genes because most identified genes could change clinical management for some patients. CONCLUSIONS AND RELEVANCE In a clinically representative cohort, multigene panel testing for HBOC risk assessment yielded findings likely to change clinical management for substantially more patients than does BRCA1/2 testing alone. Multigene testing in this setting is likely to alter near-term cancer risk assessment and management recommendations for mutation-affected individuals across a broad spectrum of cancer predisposition genes.

Correlation of Polyp Number and Family History of Colon Cancer With Germline MYH Mutations

BACKGROUND & AIMS Affected individuals with biallelic MYH mutations are believed to display multiple adenomatous polyps without evidence of vertical transmission. Our goal was to determine the detection rate of germline MYH mutations in a high-risk gastrointestinal cancer clinic population by using polyp number as a selection criterion. METHODS Patients were screened for the 2 most common MYH mutations: Y165C and G382D. The complete MYH coding region was sequenced in cases with a heterozygous mutation. RESULTS Among 45 patients with more than 15 adenomatous polyps not diagnosed with familial adenomatous polyposis, 7 (15.6%) had biallelic MYH mutations. When 122 participants from a high-risk gastrointestinal cancer clinic who did not fulfill these criteria were tested, 2 additional patients with biallelic mutations were identified. Both had young-onset colorectal cancer (age, <50 y) with fewer than 15 polyps. Surprisingly, most of the 9 patients with biallelic MYH mutations reported family histories consistent with the hereditary nonpolyposis colorectal cancer syndrome (HNPCC), with 7 cases meeting at least 1 of the Bethesda criteria, 5 cases fulfilling 3 Bethesda criteria, and 2 cases fulfilling the Amsterdam II criteria. CONCLUSIONS Most individuals with MYH mutations exhibit multiple adenomatous polyps. However, 22% of cases were missed when this was the sole criterion for germline testing. A significant number reported a strong family history of cancer that was consistent with HNPCC. MYH testing thus can be considered for patients who meet clinical criteria for HNPCC in the absence of DNA mismatch repair gene mutations.

Genetic testing by cancer site: breast.

Women in the United States have a 12% lifetime risk of developing breast cancer. Although only about 5% to 10% of all cases of breast cancer are attributable to a highly penetrant cancer predisposition gene, individuals who carry a mutation in one of these genes have a significantly higher risk of developing breast cancer, as well as other cancers, over their lifetime compared with the general population. The ability to distinguish those individuals at high risk allows health care providers to intervene with appropriate counseling and education, surveillance, and prevention-with the overall goal of improved survival for these individuals. This article focuses on the identification of patients at high risk for breast cancer and provides an overview of the clinical features, cancer risks, causative genes, and medical management for the most clearly described hereditary breast cancer syndromes. Newer genes that have also been implicated in familial breast cancer are also briefly reviewed.

Impact of genetic testing on endometrial cancer risk-reducing practices in women at risk for Lynch syndrome.

OBJECTIVE Due to the increased lifetime risk of endometrial cancer (EC), guidelines recommend that women with Lynch syndrome (LS) age ≥ 35 undergo annual EC surveillance or prophylactic hysterectomy (PH). The aim of this study was to examine the uptake of these risk-reducing strategies. METHODS The study population included women meeting clinical criteria for genetic evaluation for LS. Data on cancer risk-reducing behaviors were collected from subjects enrolled in two distinct studies: (1) a multicenter cross-sectional study involving completion of a one-time questionnaire, or (2) a single-center longitudinal study in which subjects completed questionnaires before and after undergoing genetic testing. The main outcome was uptake of EC risk-reducing practices. RESULTS In the cross-sectional cohort, 58/77 (75%) women at risk for LS-associated EC reported engaging in EC risk-reduction. Personal history of genetic testing was associated with uptake of EC surveillance or PH (OR 17.1; 95% CI 4.1-70.9). Prior to genetic testing for LS, 26/40 (65%) women in the longitudinal cohort reported engaging in EC risk-reduction. At one-year follow-up, 16/16 (100%) mismatch repair (MMR) gene mutation carriers were adherent to guidelines for EC risk-reduction, 9 (56%) of whom had undergone PH. By three-year follow-up, 11/16 (69%) MMR mutation carriers had undergone PH. Among women with negative or uninformative genetic test results, none underwent PH after testing. CONCLUSIONS Genetic testing for LS is strongly associated with uptake of EC risk-reducing practices. Women found to have LS in this study underwent prophylactic gynecologic surgery at rates comparable to those published for BRCA1/2 mutation carriers.

A Rapid Systematic Review of Outcomes Studies in Genetic Counseling

As healthcare reimbursement is increasingly tied to value-of-service, it is critical for the genetic counselor (GC) profession to demonstrate the value added by GCs through outcomes research. We conducted a rapid systematic literature review to identify outcomes of genetic counseling. Web of Science (including PubMed) and CINAHL databases were systematically searched to identify articles meeting the following criteria: 1) measures were assessed before and after genetic counseling (pre-post design) or comparisons were made between a GC group vs. a non-GC group (comparative cohort design); 2) genetic counseling outcomes could be assessed independently of genetic testing outcomes, and 3) genetic counseling was conducted by masters-level genetic counselors, or non-physician providers. Twenty-three papers met the inclusion criteria. The majority of studies were in the cancer genetic setting and the most commonly measured outcomes included knowledge, anxiety or distress, satisfaction, perceived risk, genetic testing (intentions or receipt), health behaviors, and decisional conflict. Results suggest that genetic counseling can lead to increased knowledge, perceived personal control, positive health behaviors, and improved risk perception accuracy as well as decreases in anxiety, cancer-related worry, and decisional conflict. However, further studies are needed to evaluate a wider array of outcomes in more diverse genetic counseling settings.

Professional Challenges in Cancer Genetic Testing: Who Is the Patient?

In the genetic counseling setting, the health care provider can be challenged by opposing duties to members of the same family: protecting the privacy of the patient identified with a gene mutation and the ethical obligation to warn at-risk relatives. In a situation of nondisclosure between members of a family with a known disease-predisposing mutation, this type of dilemma can present in acute form for the provider who cares for different members of the family. This can hinder effective medical decision making. To minimize this effect, we recommend detailed pretest genetic counseling steps to empower the patient to communicate with their at-risk relatives their intent to pursue testing and willingness to share information. In addition, post-test counseling should reiterate the implications of a positive result for at-risk relatives and conclude with a written summary that patients can share with their family.

A tailored approach to BRAF and MLH1 methylation testing in a universal screening program for Lynch syndrome

To determine the correlation between BRAF genotype and MLH1 promoter methylation in a screening program for Lynch syndrome (LS), a universal screening program for LS was established in two medical centers. Tumors with abnormal MLH1 staining were evaluated for both BRAF V600E genotype and MLH1 promoter methylation. Tumors positive for both were considered sporadic, and genetic testing was recommended for all others. A total 1011 colorectal cancer cases were screened for Lynch syndrome, and 148 (14.6%) exhibited absent MLH1 immunostaining. Both BRAF and MLH1 methylation testing were completed in 126 cases. Concordant results (both positive or both negative) were obtained in 86 (68.3%) and 16 (12.7%) cases, respectively, with 81% concordance overall. The positive and negative predictive values for a BRAF mutation in predicting MLH1 promoter methylation were 98.9% and 41%, respectively, and the negative predictive value fell to 15% in patients ≥70 years old. Using BRAF genotyping as a sole test to evaluate cases with absent MLH1 staining would have increased referral rates for genetic testing by 2.3-fold compared with MLH1 methylation testing alone (31% vs 13.5%, respectively, P<0.01). However, a hybrid approach that reserves MLH1 methylation testing for BRAF wild-type cases only would significantly decrease the number of methylation assays performed and reduce the referral rate for genetic testing to 12.7%. A BRAF mutation has an excellent positive predictive value but poor negative predictive value in predicting MLH1 promoter methylation. A hybrid use of these tests may reduce the number of low-risk patients referred to genetic counseling and facilitate wider implementation of Lynch syndrome screening programs.

Pathologic Findings in Prophylactic and Nonprophylactic Hysterectomy Specimens of Patients With Lynch Syndrome.

Women with Lynch syndrome (LS) have a high risk of developing endometrial carcinoma (EC) and, less frequently, ovarian carcinoma. As EC not uncommonly is the first malignancy, prophylactic hysterectomy (PH) has been increasingly implemented. In this study, we report the clinicopathologic features of a series of 70 LS patients who underwent either PH (n=39) or nonprophylactic hysterectomy (NPH) (n=31) at 3 tertiary referral centers. Among the 39 patients with PH, 2 had endometrial tumors seen grossly, whereas 37 showed no macroscopic lesions. Total inclusion of the endometrium was performed in 24/39 (61.5%). Abnormal histologic findings were identified in 9/39 (23.1%) PHs: 3 endometrial endometrioid carcinomas (EECs), including the 2 macroscopic and 1 microscopic (0.6 cm), and 4 atypical and 6 nonatypical hyperplasias. NPH included those performed for endometrial and ovarian cancer treatment. Tumor sampling followed standard protocols. ECs comprised 26 EECs and 1 clear cell carcinoma, with a median size of 3.7 cm. Hyperplasia was observed in 10 (33.3%) as background in EC, in 4 showing atypia. Eight (29.6%) tumors were centered in the lower uterine segment (all EECs). EECs were predominantly well differentiated (53.8%) and FIGO stage I (77.8%). A papillary architecture was common (51.9%) and associated with microcystic elongated and fragmented foci in 4. Mucinous differentiation was observed in 25.9% of endometrial tumors, typically representing <10%. Most endometrial tumors (81.5%) showed tumor-infiltrating lymphocyte counts ≥42/10 high-power fields. Four tumors showed extensive necrosis. Eight patients had ovarian tumors (4 synchronous), including 2 endometrioid carcinomas, 2 clear cell carcinomas, 1 borderline clear cell adenofibroma, 1 Müllerian carcinoma of mixed cell types, 1 primitive neuroectodermal tumor, and 1 metastatic melanoma. Total inclusion of the endometrium should be done in all LS patients’ surgical specimens without macroscopic lesions as some of these patients harbor preneoplastic or neoplastic conditions treatable at an early stage. The phenotype of LS-associated endometrial and ovarian tumors is variable and frequently includes features not commonly observed in sporadic cancers, but in our experience carcinomas were in general low grade and low stage.

Which individuals undergoing BRACAnalysis need BART testing

Deleterious mutations in BRCA1 and BRCA2 include those identified by sequencing technology as well as large genomic rearrangements (LGR). The main testing laboratory in the United States, Myriad Genetics Laboratory (MGL), has defined criteria for inclusion of LGR testing (i.e., BRACAnalysis Rearrangement Test, or BART™) when BRCA1 and BRCA2 testing is ordered. We were interested in determining how many of our patients with LGR mutations in BRCA1 and BRCA2 fulfilled these MGL criteria. A retrospective chart review was performed on all individuals who underwent genetic testing at our institution since August 2006. Individuals who underwent LGR testing were classified as either having or not having a LGR in BRCA1 or BRCA2. Each individuals history was classified as meeting MGL defined LGR criteria, meeting criteria using third-degree relatives, or not meeting criteria. A total of 257 BART tests were ordered at our institution from August 2006 to August 2009. Five individuals (1.9%) had an LGR mutation. Two LGR were identified in patients who met MGL defined LGR criteria. One LGR was identified in a patient that met MGL defined LGR criteria only when using third-degree relatives. Two LGR were identified in individuals who did not meet MGL defined criteria. LGR are present in individuals who do not have a high pretest probability of carrying a mutation in BRCA1 or BRCA2. These data suggest that when BRCA1 and BRCA2 genetic testing is performed, testing should always include LGR testing so that the results are the most comprehensive and reliable.