[Von Hippel-Lindau disease].

Overview All cancers develop as a result of mutations in certain genes, such as those involved in the regulation of cell growth and/or DNA repair,1,2 but not all of these mutations are inherited from a parent. For example, sporadic mutations can occur in somatic/ tumor cells only, and de novo mutations can occur for the first time in a germ cell (i.e., egg or sperm) or in the fertilized egg itself during early embryogenThe NCCN

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Genetic/familial high-risk assessment: breast and ovarian.

Background. Improvements in screening techniques have made significant contributions to the early detection of breast cancer. Physicians thus face the task of providing appropriate screening schedules for their patients. One group for whom this is particularly important are those women with a family history of breast cancer.

Methods. In this report, data from the Cancer and Steroid Hormone Study, a population-based, case-control study conducted by the Centers for Disease Control, are used to provide age-specific risk estimates of breast cancer for women with a family history of breast cancer. The data set includes 4730 patients with histologically confirmed breast cancer age 20–54 years and 4688 control subjects who were frequency matched to patients by geographic region and 5-year age intervals. The data set also includes family histories of breast cancer in mothers and sisters of both patients and control subjects.

Results. Genetic models fit previously to these data by the authors have provided evidence for a rare autosomal dominant allele that results in increased susceptibility to breast cancer. In addition, these models predict that women who carry the allele are at greater risk of developing breast cancer at any age than are women who do not carry the allele. The increase in risk in carriers versus noncarriers does, however, decrease with increasing age. Based on the parameters of this model, age-specific risks for a woman with one or more relatives affected with breast cancer at various ages at onset are given.

Conclusions. These tables can be used for the purpose of counseling women at high risk of breast cancer development, that is, women with a family history of breast cancer.

Autosomal Dominant Inheritance of Early-Onset Breast Cancer: Implications for Risk Prediction

ContextIdentifying families at high risk for the Lynch syndrome (ie, hereditary nonpolyposis colorectal cancer) is critical for both genetic counseling and cancer prevention. Current clinical guidelines are effective but limited by applicability and cost.ObjectiveTo develop and validate a genetic counseling and risk prediction tool that estimates the probability of carrying a deleterious mutation in mismatch repair genes MLH1, MSH2, or MSH6 and the probability of developing colorectal or endometrial cancer.Design, Setting, and PatientsExternal validation of the MMRpro model was conducted on 279 individuals from 226 clinic-based families in the United States, Canada, and Australia (referred between 1993-2005) by comparing model predictions with results of highly sensitive germline mutation detection techniques. MMRpro models the autosomal dominant inheritance of mismatch repair mutations, with parameters based on meta-analyses of the penetrance and prevalence of mutations and of the predictive values of tumor characteristics. The model's prediction is tailored to each individual's detailed family history information on colorectal and endometrial cancer and to tumor characteristics including microsatellite instability.Main Outcome MeasureAbility of MMRpro to correctly predict mutation carrier status, as measured by operating characteristics, calibration, and overall accuracy.ResultsIn the independent validation, MMRpro provided a concordance index of 0.83 (95% confidence interval, 0.78-0.88) and a ratio of observed to predicted cases of 0.94 (95% confidence interval, 0.84-1.05). This results in higher accuracy than existing alternatives and current clinical guidelines.ConclusionsMMRpro is a broadly applicable, accurate prediction model that can contribute to current screening and genetic counseling practices in a high-risk population. It is more sensitive and more specific than existing clinical guidelines for identifying individuals who may benefit from MMR germline testing. It is applicable to individuals for whom tumor samples are not available and to individuals in whom germline testing finds no mutation.

https://jamanetwork.com/journals/jama/articlepdf/203428/joc60127.pdf

Prediction of Germline Mutations and Cancer Risk in the Lynch Syndrome

The NCCN Guidelines for Genetic/Familial High-Risk Assessment: Breast, Ovarian, and Pancreatic provide recommendations for genetic testing and counseling for hereditary cancer syndromes, and risk management recommendations for patients who are diagnosed with syndromes associated with an increased risk of these cancers. The NCCN panel meets at least annually to review comments, examine relevant new data, and reevaluate and update recommendations. These NCCN Guidelines Insights summarize the panel's discussion and most recent recommendations regarding criteria for high-penetrance genes associated with breast and ovarian cancer beyond BRCA1/2, pancreas screening and genes associated with pancreatic cancer, genetic testing for the purpose of systemic therapy decision-making, and testing for people with Ashkenazi Jewish ancestry.

NCCN Guidelines Insights: Genetic/Familial High-Risk Assessment: Breast, Ovarian, and Pancreatic, Version 1.2020.

These cancer genetic counseling recommendations describe the medical, psychosocial, and ethical ramifications of identifying at-risk individuals through cancer risk assessment with or without genetic testing. They were developed by members of the Practice Issues Subcommittee of the National Society of Genetic Counselors Cancer Genetic Counseling Special Interest Group. The information contained in this document is derived from extensive review of the current literature on cancer genetic risk assessment and counseling as well as the personal expertise of genetic counselors specializing in cancer genetics. The recommendations are intended to provide information about the process of genetic counseling and risk assessment for hereditary cancer disorders rather than specific information about individual syndromes. Key components include the intake (medical and family histories), psychosocial assessment (assessment of risk perception), cancer risk assessment (determination and communication of risk), molecular testing for hereditary cancer syndromes (regulations, informed consent, and counseling process), and follow-up considerations. These recommendations should not be construed as dictating an exclusive course of management, nor does use of such recommendations guarantee a particular outcome. These recommendations do not displace a health care provider's professional judgment based on the clinical circumstances of a client.

https://onlinelibrary.wiley.com/doi/pdf/10.1023/B%3AJOGC.0000018821.48330.77

Susan Donlon

Papers

Genetic Cancer Risk Assessment and Counseling: Recommendations of the National Society of Genetic Counselors