A range of testing methodologies are needed to identify pathogenic changes in the BRCA 1 or BRCA 2 genes including:
- copy number analysis (e.g. MLPA).
Information about DNA tests and testing laboratories is available from:
Where possible, BRCA1 and BRCA2 testing should be done as part of a panel test (refer to Breast cancer panel testing, Ovarian cancer (epithelial) panel testing, Pancreatic cancer panel testing or Prostate cancer panel testing). Clinical features and/or additional family history may guide choice of additional genes (CDH1, TP53, PTEN, MMR).
If a decision is made to test these genes as part of a cancer gene panel, care should be taken to select a panel where the individual genes tested have both clinical validity and clinical utility.
If these genes are tested using genomic sequencing (“next generation sequencing” or NGS), and testing has not identified a pathogenic variant, the value of testing using another methodology (e.g. MLPA, Sanger sequencing) should be considered in high risk families.
If genetic testing in DNA from peripheral blood is uninformative, testing of two or more different tumour samples may be indicated to assess for mosaicism.