Kristen Shannon

Heterozygous Germline ATM Mutations Do Not Contribute to Radiation-Associated Malignancies After Hodgkin's Disease

PURPOSE The successful treatment of Hodgkins disease has been associated with an increased incidence of secondary malignancies. To investigate whether genetic factors contribute to the development of secondary tumors, we collected family cancer histories and performed mutational analysis of the ataxia-telangiectasia (AT) gene, ATM, in a cohort of Hodgkins disease survivors with secondary malignancies. ATM was chosen for evaluation because of the increased radiosensitivity of cells derived from AT patients and obligate heterozygotes and the epidemiologic observation that AT carriers are at increased risk for radiation-induced breast cancer. PATIENTS AND METHODS Fifty-two patients who developed one or more neoplasms after treatment for Hodgkins disease participated in this study. Personal and family histories of cancer were obtained through patient interviews and review of medical records. ATM mutational analysis was performed using a yeast-based protein truncation assay. RESULTS Seventy-six secondary neoplasms were observed in this cohort of 52 Hodgkins disease survivors, with 18 patients (35%) developing more than one secondary neoplasm. Positive family histories of cancer were present in 11 (21%) of 52 patients, compared with three (4%) of 68 Hodgkins disease patients in a comparison cohort who did not develop secondary neoplasms (P =.008; Fishers exact test). No germline ATM mutations were identified, resulting in an estimated AT carrier frequency in this population of 0% (90% confidence interval, 0% to 4%). CONCLUSION Analysis of the number of tumors per individual and the family history of cancer in our cohort suggests that genetic factors may contribute to development of secondary neoplasms in a subset of Hodgkins disease survivors. Mutational analysis, however, does not support a significant role for heterozygous truncating ATM mutations. Future studies evaluating other genes involved in DNA damage response pathways are warranted.

Germline mutations in PTEN are an infrequent cause of genetic predisposition to breast cancer

Heterozygous germline mutations in PTEN are responsible for most cases of Cowden Syndrome, a rare familial trait characterized by hamartomas and by predisposition to cancer of the breast and thyroid. The variable and often subtle clinical findings that characterize Cowden Syndrome are frequently unrecognized, raising the possibility that germline PTEN mutations may confer susceptibility to breast cancer in women who have not been diagnosed with this syndrome. To determine whether such mutations contribute to genetic predisposition to breast cancer within the general population, we analysed a cohort of women with early-onset breast cancer (<age 40), a subset of the population at increased risk for genetic susceptibility. Lymphoblast cell lines were analysed using either direct nucleotide sequencing (28 cases), denaturing gradient gel electrophoresis (DGGE) (34 cases) or a yeast-based truncation assay (110 cases). No definitive, truncating mutations were observed in 172 patients. Missense changes were noted in the germline of 2/60 patients analysed by direct nucleotide sequencing or DGGE, including a non-conservative amino acid substitution within the phosphatase domain, but neither showed loss of the wild-type allele in the corresponding breast tumor specimen. We conclude that germline mutations in PTEN are an uncommon cause of genetic predisposition to breast cancer within the general population.

Facilitating Informed Decisions Regarding Microsatellite Instability Testing Among High-Risk Individuals Diagnosed With Colorectal Cancer

PURPOSE To evaluate the impact of a CD-ROM intervention in the education of patients with suspected Lynch syndrome (LS) about microsatellite instability (MSI) and immunohisochemistry (IHC) testing. PATIENTS AND METHODS Two hundred thirteen patients meeting Bethesda criteria were randomly assigned to receive either a brief educational session with a health educator (n = 105) or a brief educational session plus a CD-ROM (n = 108). Assessments were administered at baseline and 2 weeks post-treatment. Primary outcomes included MSI and IHC knowledge and level of satisfaction with and completeness of the preparation to make the decision for MSI testing. Secondary outcomes included decisional conflict, difficulty making the decision, cancer-specific and global anxiety, and level of discussion about MSI testing with family and friends. RESULTS Participants in the education plus CD-ROM condition reported significant increases in knowledge about the MSI and IHC tests, greater satisfaction with the preparation to make a decision for testing, lower decisional conflict, and greater decisional self-efficacy. The effects of the education plus CD-ROM on most outcomes were not moderated by preintervention levels of exposure to MSI testing, family support for MSI testing, or the family history of cancer. CONCLUSION Incorporation of new media education strategies for individuals at risk for LS may be a valuable component of the informed consent process. As clinical criteria for MSI and IHC testing continue to expand, the need for alternative educational approaches to meet this increased demand could be met by the self-administered computer-based strategy that we described.

Hereditary melanoma: Update on syndromes and management: Genetics of familial atypical multiple mole melanoma syndrome

Malignant melanoma is considered the most lethal skin cancer if it is not detected and treated during its early stages. About 10% of melanoma patients report a family history of melanoma; however, individuals with features of true hereditary melanoma (ie, unilateral lineage, multigenerational, multiple primary lesions, and early onset of disease) are in fact quite rare. Although many new loci have been implicated in hereditary melanoma, CDKN2A mutations remain the most common. Familial melanoma in the presence of multiple atypical nevi should raise suspicion for a germline CDKN2A mutation. These patients have a high risk of developing multiple primary melanomas and internal organ malignancies, especially pancreatic cancer; therefore, a multidisciplinary approach is necessary in many cases. The value of dermoscopic examination and total body photography performed at regular intervals has been suggested by a number of studies, and should therefore be considered for these patients and their first-degree relatives. In addition, genetic counseling with the possibility of testing can be a valuable adjunct for familial melanoma patients. This must be performed with care, however, and only by qualified individuals trained in cancer risk analysis.

Knowledge and attitudes about microsatellite instability testing among high-risk individuals diagnosed with colorectal cancer

For individuals meeting Bethesda criteria for hereditary nonpolyposis colorectal cancer syndrome, the microsatellite instability (MSI) test is recommended as a screening evaluation before proceeding to genetic testing. The MSI test is new to the medical setting, but will be increasingly used to screen patients at high risk for hereditary nonpolyposis colorectal cancer. The main goals of this study were to examine knowledge about and exposure to the MSI test among individuals considering the test, to evaluate perceived benefits and barriers to undergoing the MSI test, and to identify the demographic, medical, and psychosocial correlates of the perceived benefits and barriers to undergoing the test. One hundred and twenty-five patients completed a survey after being offered the test, but prior to making the decision whether to pursue MSI testing. Results indicated low levels of knowledge about and previous exposure to the MSI test. Participants held positive attitudes about the potential benefits of the test and perceived few barriers to undergoing the test. Motivations were similar to those cited by individuals considering other genetic tests. Participants with nonmetastatic disease, with lower perceived risk for cancer recurrence, and who reported more self-efficacy endorsed more benefits from the test. Higher levels of cancer-specific psychological distress were associated with more perceived barriers to having the test. These findings suggest that individuals considering the MSI test know very little about it but hold positive attitudes about the tests utility. More distressed patients, patients who perceive themselves at higher risk for cancer recurrence, and patients with metastatic disease might be less motivated to have the MSI test. (Cancer Epidemiol Biomarkers Prev 2007;16(10):2110–7)

Hereditary melanoma: Update on syndromes and management: Emerging melanoma cancer complexes and genetic counseling

Recent advances in cancer genomics have enabled the discovery of many cancer-predisposing genes that are being used to classify new familial melanoma/cancer syndromes. In addition to CDKN2A and CDK4, germline variants in TERT, MITF, and BAP1 have been added to the list of genes harboring melanoma-predisposing mutations. These newer entities may have escaped earlier description in part because of more advanced technologies now being used and in part because of their mixed cancer phenotype as opposed to a melanoma-focused syndrome. Dermatologists should be aware of (and be able to recognize) the clinical signs in high-risk patients in different contexts. Personal and family histories of cancer should always be sought in patients with multiple nevi or a positive history for melanoma, and should be updated annually. Various features that are unique to specific disorders, such as the appearance of melanocytic BAP1-mutated atypical intradermal tumors in cases of BAP1 melanoma syndrome, should also be recognized early. These patients should be offered regular screenings with the use of dermoscopy and total body photography, as needed. More importantly, referral to other specialists may be needed if a risk for internal malignancy is suspected. It is important to have in mind that these patients tend to develop multiple melanomas, along with various internal organ malignancies, often at younger ages; a multidisciplinary approach to their cancer screening and treatment is ideal.

Survey of unaffected BRCA and mismatch repair (MMR) mutation positive individuals.

Many individuals do not proceed with cancer predisposition testing due to fears of genetic discrimination (GD). We report the results of a survey of 47 unaffected, mutation positive individuals regarding insurance outcomes. Participants recruited from six different Cancer Risk Programs across the country were queried about their experiences with health, life, and disability insurance, as well as employment issues. Eighty-seven percent of participants carried a BRCA mutation and 87% were part of a group insurance plan at the time of testing. Forty-seven percent of participants self-paid for testing. Less than 10% of participants reported that their results were placed in the general medical record, while 43% did not know where their results were placed. Due to concerns about GD, 13% of participants stated they avoided changing jobs. Thirteen percent stated that their at-risk relatives had not undergone testing for the familial mutation due to fears about GD. Adverse events following genetic testing included two denials from private health insurers, one denial for average life insurance coverage and one denial for additional disability insurance. There were no reports of job discrimination. Results suggest fear of GD is prevalent, yet data do not support evidence that GD exists.

Cancer Genetic Counseling

Our fundamental understanding of carcinogenesis has expanded dramatically over the past five years. Of foremost importance has been the discovery of genes that, when mutated in the germline, confer high risks of specific malignancies. The translation of these laboratory findings into clinical practice has led to the creation of a new medical subspecialty termed cancer genetic counseling. Cancer genetic counseling is defined as a communication process concerning an individual’s risk of developing specific inherited forms of cancer. This risk may be higher than or similar to the general population risks of cancer. Cancer genetic counseling can, but does not always, lead to genetic testing. The genetic counseling process involves: 1) obtaining detailed family, medical, and lifestyle histories; 2) documentation of cancer-related diagnoses; 3) pedigree analysis; 4) risk assessment and counseling; 5) general discussion of options for early detection and prevention; and 6) provision of genetic testing when appropriate. This chapter provides an overview of cancer genetic counseling, including a general description of the providers and patients involved, the cancer genetic-counseling process in a high-risk clinical setting and a predisposition-testing program, the provision of genetic counseling for selected hereditary-cancer syndromes, and case examples to highlight some of the complexities inherent to this process.

A state‐wide initiative to promote genetic testing in an underserved population

Genetic testing for cancer susceptibility has been widely studied and utilized clinically. Access to genetic services in research and practice is largely limited to well‐insured, Caucasian individuals. In 2009, the Cancer Resource Foundation (CRF) implemented the Genetic Information for Treatment Surveillance and Support (GIFTSS) program to cover the out‐of‐pocket expenses associated with cancer genetic testing, targeting high‐risk individuals with limited financial means and limited health insurance coverage. Here, we (i) describe the characteristics of participants in the Massachusetts (MA) GIFTSS program and (ii) evaluate mutations found in this diverse sample. A secondary retrospective data analysis was performed using de‐identified demographic data obtained from laboratory requisition forms and cancer genetic testing result information from the laboratory source. Eligible participants were those who utilized the MA GIFFTS program from 2009 through December of 2014. Data were summarized using descriptive measures of central tendency. Participants were residents of Massachusetts who had health insurance and had a reported income within 250–400% of the federal poverty level. Genetic testing results were categorized following clinical guidelines. Overall, 123 (13%) of participants tested positive for a mutation in a cancer susceptibility gene. For those with a cancer diagnosis, 65 (12%) were found to have a positive result and 20 (7%) had a variant of uncertain significance (VUS). For those unaffected patients, 58 (15%) had a positive result and 10 (3%) were found to have a VUS. The results from this study are useful in describing genetic testing outcomes in this high‐risk underserved community. Repeatedly, the literature reports that individuals from diverse or limited resource settings are less likely to access genetic testing. Continued research efforts should be devoted to promoting the access of genetic testing in the high‐risk, underserved community.

A Strategy for Large-Scale Systematic Pan-Cancer Germline Rare Variation Analysis

Traditionally, genetic studies in cancer are focused on somatic mutations found in tumors and absent from the normal tissue. However, this approach omits inherited component of the cancer risk. We assembled exome sequences from about 2,000 patients with different types of cancers: breast cancer, colon cancer and cutaneous and ocular melanomas matched to more than 7,000 non-cancer controls. Using this dataset, we described germline variation in the known cancer genes grouped by inheritance mode or inclusion in a known cancer pathway. According to our observations, protein-truncating singleton variants in loss-of-function tolerant genes following autosomal dominant inheritance mode are driving the association signal in both genetically enriched and unselected cancer cases. We also performed separate gene-based association analysis for individual phenotypes and proposed a list of new cancer risk gene candidates. Taken together, these results extend existing knowledge of germline variation contribution to cancer onset and provide a strategy for novel gene discovery.Traditionally, genetic studies in cancer are focused on somatic mutations found in tumors and absent from the normal tissue. Identification of shared attributes in germline variation could aid discrimination of high-risk from likely benign mutations and narrow the search space for new cancer predisposing genes. Extraordinary progress made in analysis of common variation with GWAS methodology does not provide sufficient resolution to understand rare variation. To fulfill missing classification for rare germline variation we assembled datasets of whole exome sequences from >2,000 patients with different types of cancers: breast cancer, colon cancer and cutaneous and ocular melanomas matched to more than 7,000 non-cancer controls and analyzed germline variation in known cancer predisposing genes to identify common properties of disease associated mutations and new candidate cancer susceptibility genes. Lists of all cancer predisposing genes were divided into subclasses according to the mode of inheritance of the related cancer syndrome or contribution to known major cancer pathways. Out of all subclasses only genes linked to dominant syndromes presented significant rare germline variants enrichment in cases. Separate analysis of protein-truncating and missense variation in this subclass of genes confirmed significant prevalence of protein-truncating variants in cases only in loss-of-function tolerant genes (pLI 0.9). Taken together, our findings provide insights into the distribution and types of mutations underlying inherited cancer predisposition.