Retesting of women who are negative for a BRCA1 and BRCA2 mutation using a 20-gene panel

J Med Genet. 2020 Jun;57(6):380-384. doi: 10.1136/jmedgenet-2019-106403. Epub 2019 Nov 29.

Abstract

Background: The value of retesting women who previously tested negative for a pathogenic variant (mutation) in BRCA1 and BRCA2 using an expanded panel of breast and ovarian cancer genes is unclear.

Methods: We studied 110 BRCA1/2-negative women who were retested using a panel of 20 breast and/or ovarian cancer susceptibility genes at the Advanced Molecular Diagnostics Laboratory (AMDL) at Mount Sinai Hospital in Toronto between March 2017 and March 2019. All patients had previously tested negative for BRCA pathogenic variants at the AMDL between January 2012 and March 2018 and were subsequently referred for retesting by their physician.

Results: Overall, six pathogenic variants in genes other than BRCA1 and BRCA2 were found (prevalence 5.5%). There were two pathogenic variants found in RAD51C, and one found in each of BRIP1, PALB2, PMS2 and PTEN. The prevalence of pathogenic variants was 6.5% for women affected with cancer (6 of 93), including 4.9% for women with breast cancer (4 of 82) and 22.2% for women with ovarian cancer (2 of 9). None of the 17 unaffected women had a clinically significant or pathogenic variant. There were 44 women (40%) for whom the result of the panel test was inconclusive due to the detection of a variant of uncertain significance.

Conclusions: Our findings indicate that the retesting of BRCA1/2-negative individuals with an expanded panel of 20 breast and ovarian cancer genes can produce clinically relevant results, with a yield of 5.5% for pathogenic variants in genes other than BRCA1 and BRCA2.

Keywords: BRCA1/2 negative; gene panel; hereditary breast and ovarian cancer; retesting.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • BRCA1 Protein / genetics*
  • BRCA2 Protein / genetics*
  • Breast Neoplasms / genetics*
  • Breast Neoplasms / pathology
  • DNA-Binding Proteins / genetics
  • Fanconi Anemia Complementation Group N Protein / genetics
  • Fanconi Anemia Complementation Group Proteins / genetics
  • Female
  • Gene Expression Regulation, Neoplastic / genetics
  • Hereditary Breast and Ovarian Cancer Syndrome / genetics*
  • Hereditary Breast and Ovarian Cancer Syndrome / pathology
  • Humans
  • Middle Aged
  • Mismatch Repair Endonuclease PMS2 / genetics
  • PTEN Phosphohydrolase / genetics
  • RNA Helicases / genetics

Substances

  • BRCA1 Protein
  • BRCA1 protein, human
  • BRCA2 Protein
  • BRCA2 protein, human
  • DNA-Binding Proteins
  • Fanconi Anemia Complementation Group N Protein
  • Fanconi Anemia Complementation Group Proteins
  • PALB2 protein, human
  • RAD51C protein, human
  • PTEN Phosphohydrolase
  • PMS2 protein, human
  • Mismatch Repair Endonuclease PMS2
  • BRIP1 protein, human
  • RNA Helicases