Presentation Title

Evaluation of Current Genetic Testing Criteria Used by BC Cancer Agency's Hereditary Cancer Program

Format of Presentation

Poster to be presented Friday March 31, 2017

Abstract

Cancer genetics services for the population of British Columbia, Canada are provided solely by the BC Cancer Agency’s Hereditary Cancer Program (HCP). In October 2014, the HCP introduced a multi-gene panel for affected adults meeting specific phenotypic-based testing criteria for at least one syndrome on the panel. Testing criteria for Hereditary Breast and Ovarian Cancer Syndrome (BRCA1, BRCA2) have shown variable mutation detection rates. Based on preliminary data, the criterion of 3 breast cancer (BrCa) cases in a family with one diagnosed at age 50 years or younger has a mutation detection rate of only 4%. 179 patients met the criterion of 3 BrCa cases with one diagnosed at age 50 or younger, 8 of which tested positive for presumed pathogenic variants in BRCA1 or BRCA2. We calculated BRCA1/2 mutation probability scores using BOADICEA and Manchester risk prediction models for all mutation positive pedigrees and 10% of uninformative pedigrees. The mean BOADICEA scores for uninformative versus positive pedigrees were 13.8% and 23.1%, respectively (p= 0.41), and the mean Manchester scores were 18 and 24, respectively (p= 0.21). While risk prediction methods BOADICEA and Manchester have higher mean scores for positive versus uninformative pedigrees, the range in scores was large. Our preliminary findings reveal the variability within families that meet this criterion. Further analysis of families with uninformative testing may help clarify the subset of cases for which targeted enrichment within the current criterion could improve mutation detection rates.

Department

Biological Sciences

Faculty Advisor

James E. J. Bedard

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Evaluation of Current Genetic Testing Criteria Used by BC Cancer Agency's Hereditary Cancer Program

Cancer genetics services for the population of British Columbia, Canada are provided solely by the BC Cancer Agency’s Hereditary Cancer Program (HCP). In October 2014, the HCP introduced a multi-gene panel for affected adults meeting specific phenotypic-based testing criteria for at least one syndrome on the panel. Testing criteria for Hereditary Breast and Ovarian Cancer Syndrome (BRCA1, BRCA2) have shown variable mutation detection rates. Based on preliminary data, the criterion of 3 breast cancer (BrCa) cases in a family with one diagnosed at age 50 years or younger has a mutation detection rate of only 4%. 179 patients met the criterion of 3 BrCa cases with one diagnosed at age 50 or younger, 8 of which tested positive for presumed pathogenic variants in BRCA1 or BRCA2. We calculated BRCA1/2 mutation probability scores using BOADICEA and Manchester risk prediction models for all mutation positive pedigrees and 10% of uninformative pedigrees. The mean BOADICEA scores for uninformative versus positive pedigrees were 13.8% and 23.1%, respectively (p= 0.41), and the mean Manchester scores were 18 and 24, respectively (p= 0.21). While risk prediction methods BOADICEA and Manchester have higher mean scores for positive versus uninformative pedigrees, the range in scores was large. Our preliminary findings reveal the variability within families that meet this criterion. Further analysis of families with uninformative testing may help clarify the subset of cases for which targeted enrichment within the current criterion could improve mutation detection rates.