Lisa Susswein

Polymorphisms in the VKORC1 gene are strongly associated with warfarin dosage requirements in patients receiving anticoagulation

Background: Warfarin is a mainstay of therapy for conditions associated with an increased risk of thromboembolic events. However, the use of this common agent is fraught with complications and little is known regarding inter-individual variation in warfarin response. Objective: We tested for association between single nucleotide polymorphisms (SNPs) in VKORC1 and CYP2C9 and average weekly warfarin dose required to maintain patients at their desired anticoagulation target. Methods: The sample consisted of 93 European-American patients from anticoagulation clinics at the University of North Carolina at Chapel Hill. Data on mean weekly warfarin dose were collected over a mean treatment period of 20.6 months. ANCOVA models were used and haplotype analysis was performed. Results: Three of six VKORC1 SNPs were found to be very strongly associated with the average warfarin dose required to achieve the target international normalised ratio (INR; p<0.0001). The mean weekly dose by genotype ranged from approximately 27 to 47 mg. There was no evidence for an association between either of the two CYP2C9 polymorphisms studied, CYP2C9*2 and CYP2C9*3. CYP2C9*3 was significantly (p = 0.05) associated with average warfarin dosage after adjustment for VKORC1*1173. Conclusions: These results are of considerable clinical interest and confirm recently published results regarding the role of these two genes in modifying warfarin metabolism and maintenance dosage. The consistent findings regarding the role of VKORC1 and CYP2C9 in warfarin metabolism and maintenance dosage represent a clinically useful proof of principal for the use of pharmacogenomic information in medicine and may lead to improved understanding of warfarin’s actions.

Telephoned BRCA1/2 Genetic Test Results: Prevalence, Practice, and Patient Satisfaction.

While the traditional model of genetic evaluation for breast cancer risk recommended face-to-face disclosure of genetic testing results, BRCA1/2 testing results are increasingly provided by telephone. The few existing studies on telephone genetic counseling provide conflicting results about its desirability and efficacy. The current study aimed to (1) Estimate the prevalence among genetic counselors of providing BRCA1/2 genetic test results by phone (2) Assess patient satisfaction with results delivered by telephone versus in-person. A survey was sent to members of the Familial Cancer Risk Counseling Special Interest Group via the NSGC listserve and was completed by 107 individuals. Additionally, 137 patients who had received BRCA genetic testing results either by phone or in-person at UNC Chapel Hill Cancer Genetics Clinic were surveyed regarding satisfaction with the mode of their BRCA1/2 results delivery. The genetic counseling survey revealed that the majority of responding counselors (92.5%) had delivered BRCA1/2 genetic test results by telephone. Patients having received results either in person or by phone reported no difference in satisfaction. Most patients chose to receive results by phone and those given a choice of delivery mode reported significantly higher satisfaction than those who did not have a choice. Those who waited less time to receive results once they knew they were ready also reported higher satisfaction. This study found supportive results for the routine provision of BRCA1/2 genetic test results by telephone. Results suggest that test results should be delivered as swiftly as possible once available and that offering patients a choice of how to receive results is desirable. These are especially important issues as genetic testing becomes more commonplace in medicine.

Increased Uptake of BRCA1/2 Genetic Testing Among African American Women With a Recent Diagnosis of Breast Cancer

PURPOSE Studies suggest that African American women are less likely to pursue BRCA1/2 genetic testing than white women. However, such studies are often confounded by unequal access to care. METHODS Data from 132 African American and 636 white women, obtained from a clinical database at the University of North Carolina (Chapel Hill, NC) between 1998 and 2005, were analyzed to assess BRCA1/2 genetic testing uptake. Importantly, the clinical setting minimized barriers of both cost and access. Race and time of new breast cancer diagnosis (recent v > 1 year before genetic evaluation) were assessed for association with BRCA1/2 testing uptake using multivariable logistic regression models. RESULTS Both race (P = .0082) and a recent diagnosis of breast cancer (P = .014) were independently associated with testing uptake. African American women had a lower estimated odds of pursuing testing than white women (odds ratio [OR], 0.54; 95%CI, 0.34 to 0.85), and women with a recent diagnosis had a higher OR than those with a remote diagnosis (OR, 1.58; 95% CI, 1.10 to 2.29). In a race-stratified analysis, there was no statistical evidence for association between recent status and testing uptake in the larger white stratum (OR, 1.38, P = .13) while there was for the smaller African American sample (OR, 2.77, P = .018). The test of interaction between race and remote status was not significant (P = .15). CONCLUSION African American race was associated with an overall decreased uptake of BRCA1/2 genetic testing, even when barriers of ascertainment and cost were minimized. However, among African American women, a recent diagnosis of breast cancer was associated with substantially increased uptake of testing.

Genetics and the young woman with breast cancer

While many individual risk factors have been defined for breast cancer, a family history was recognized long ago as one of the most potent. Mutations within BRCA1 or BRCA2, both identified about 10 years ago, are responsible for the majority of inherited breast cancer. By virtue of her age alone, a young woman diagnosed with breast cancer has a greatly elevated probability to carry a BRCA mutation. Other risk factors, including a personal or family history of ovarian cancer, bilateral breast cancer or Jewish ancestry, only serve to increase that chance. It is critical that clinicians caring for a young woman understand their patients elevated risk to carry such a mutation and thoughtfully investigate this risk. Upon identification of a mutation in a young woman there are many consequences which necessitate careful consideration of various treatment and preventative options including prophylactic mastectomy and oophorectomy. Finally, the diagnosis of breast cancer in a young woman and the attendant genetic implications have immediate and serious consequences for her family members. Genetic professionals can help navigate the complex technical and psychosocial issues. This chapter explores the molecular, clinical and ethical intricacies of BRCA genetic testing.

Factors Associated with African Americans’ Enrollment in a National Cancer Genetics Registry

This study explored whether reactions to the Cancer Genetics Network (CGN) or CGN enrollment differed by receipt of a standard informational brochure versus a targeted version addressing factors previously associated with African Americans’ health behavior decisions and research participation. The 262 participants, identified through tumor registries or clinic contacts, were mailed brochures and completed phone interviews. When asked whether – based on the brochure – they were or were not ‘leaning toward’ CGN enrollment, about 75% of both standard and targeted groups reported leaning toward. When given the opportunity at the end of the interview, 68% enrolled in the CGN. Trust was strongly related to enrollment. Less education, less satisfaction with cancer care, and individualistic rather than collective orientation were associated with lower trust. Education was also bivariately associated with enrollment, but mediation analysis indicated that the operational mechanism of education’s influence on enrollment was through trust.

Metastatic medullary thyroid cancer in a pediatric patient with MEN 2B: Emphasis on the need for early recognition of extrathyroidal clinical findings associated with MEN 2B

This pediatric case demonstrates the necessity for early clinical recognition of multiple endocrine neoplasia type 2B (MEN 2B). Although MEN 2B itself is, indeed, a rare syndrome, it can present with deceptively common extrathyroidal complaints, including gastrointestinal and ophthalmological signs and symptoms, in addition to those features more typically expected to be seen with MEN 2B (e.g., mucosal neuromas, Marfanoid habitus, thyroid nodules). Although these presenting complaints may appear benign and can often be misleading, such as in the present case, the aggressive nature of medullary thyroid cancer (MTC) in MEN 2B necessitates early detection of the associated clinical features. This case report outlines the clinical constellation of signs and symptoms characterizing MEN 2B, with emphasis on the need for familiarity with extrathyroidal findings. Such recognition by the general practitioner is essential, to provide early identification of this life-threatening disorder. Case Report

Attitudes and Practice of Genetic Counselors Regarding Anonymous Testing for BRCA1/2

Patients and clinicians alike view anonymous testing as a potential way to avoid perceived risks of genetic testing such as insurance and employment discrimination and the potential loss of privacy. To assess their experience with and attitudes towards anonymous testing for BRCA1/2, genetic counselors were invited to complete an internet-based survey via the NSGC Familial Cancer Risk Counseling Special Interest Group (FCRC-SIG) listerv. A majority of the 115 respondents (70%) had received requests from patients for anonymous BRCA1/2 testing at some point in their careers and 43% complied with this request. Most counselors, however, encountered such requests infrequently, 1–5 times per year. Although genetic counselors do not generally encourage anonymous testing and over a third of respondents feel it should never be offered, a substantial subset support its use under specific circumstances. In general, a strong consensus exists among counselors that anonymous testing should not be offered routinely. In light of the current legislative landscape, it is of note that a substantial proportion of respondents (42.7%) cited the threat of life insurance discrimination as a reason for pursuing AT, and fewer cited health insurance (30.0%) or employment discrimination (29.1%) as justifications. Since there exists no federal legislative protections against discrimination by life insurance companies, it makes sense that genetic counselors were more responsive to this issue as opposed to the threat of discrimination in health insurance and employment.

MSH6 and PMS2 germ-line pathogenic variants implicated in Lynch syndrome are associated with breast cancer

PurposeAn association of Lynch syndrome (LS) with breast cancer has been long suspected; however, there have been insufficient data to address this question for each of the LS genes individually.MethodsWe conducted a retrospective review of personal and family history in 423 women with pathogenic or likely pathogenic germ-line variants in MLH1 (N = 65), MSH2 (N = 94), MSH6 (N = 140), or PMS2 (N = 124) identified via clinical multigene hereditary cancer testing. Standard incidence ratios (SIRs) of breast cancer were calculated by comparing breast cancer frequencies in our study population with those in the general population (Surveillance, Epidemiology, and End Results 18 data).ResultsWhen evaluating by gene, the age-standardized breast cancer risks for MSH6 (SIR = 2.11; 95% confidence interval (CI), 1.56–2.86) and PMS2 (SIR = 2.92; 95% CI, 2.17–3.92) were associated with a statistically significant risk for breast cancer whereas no association was observed for MLH1 (SIR = 0.87; 95% CI, 0.42–1.83) or MSH2 (SIR = 1.22; 95% CI, 0.72–2.06).ConclusionOur data demonstrate that two LS genes, MSH6 and PMS2, are associated with an increased risk for breast cancer and should be considered when ordering genetic testing for individuals who have a personal and/or family history of breast cancer.

Germline pathogenic variants identified in women with ovarian tumors

OBJECTIVE The recognition of genes implicated in ovarian cancer risk beyond BRCA1, BRCA2, and the Lynch syndrome genes has increased the variety of testing options available to providers and patients. We report the frequency of pathogenic variants identified among individuals with ovarian cancer undergoing clinical genetic testing via a multi-gene hereditary cancer panel. METHODS Genetic testing of up to 32 genes using a hereditary cancer panel was performed on 4439 ovarian cancer cases, and results were analyzed for frequency of pathogenic variants. Statistical comparisons were made using t-tests and Fishers exact tests. RESULTS The positive yield was 13.2%. While BRCA1/2 pathogenic variants were most frequent, one third (33.7%) of positive findings were in other homologous recombination genes, and accounted for over 40.0% of findings in endometrioid and clear cell cases. Women with a personal history of breast cancer (22.1%), who reported a family history of ovarian cancer (17.7%), and/or serous histology (14.7%) were most likely to harbor a pathogenic variant. Those with very early onset (<30 years) and late onset (≥70 years) ovarian cancer had low positive yields. CONCLUSIONS Our study highlights the genetic heterogeneity of ovarian cancer, showing that a large proportion of cases are not due to BRCA1/2 and the Lynch syndrome genes, but still have an identifiable hereditary basis. These findings substantiate the utility of multi-gene panel testing in ovarian cancer care regardless of age at diagnosis, family history, or histologic subtype, providing evidence for testing beyond BRCA1/2 and the Lynch syndrome genes.