TY - JOUR T1 - Reclassification of <em>BRCA1</em> and <em>BRCA2</em> variants of uncertain significance: a multifactorial analysis of multicentre prospective cohort JF - Journal of Medical Genetics JO - J Med Genet SP - 794 LP - 802 DO - 10.1136/jmedgenet-2018-105565 VL - 55 IS - 12 AU - Jee-Soo Lee AU - Sohee Oh AU - Sue Kyung Park AU - Min-Hyuk Lee AU - Jong Won Lee AU - Sung-Won Kim AU - Byung Ho Son AU - Dong-Young Noh AU - Jeong Eon Lee AU - Hai-Lin Park AU - Man Jin Kim AU - Sung Im Cho AU - Young Kyung Lee AU - Sung Sup Park AU - Moon-Woo Seong Y1 - 2018/12/01 UR - http://jmg.bmj.com/content/55/12/794.abstract N2 - Background BRCA1 and BRCA2 (BRCA1/2) variants classified ambiguously as variants of uncertain significance (VUS) are a major challenge for clinical genetic testing in breast cancer; their relevance to the cancer risk is unclear and the association with the response to specific BRCA1/2-targeted agents is uncertain. To minimise the proportion of VUS in BRCA1/2, we performed the multifactorial likelihood analysis and validated this method using an independent cohort of patients with breast cancer.Methods We used a data set of 2115 patients with breast cancer from the nationwide multicentre prospective Korean Hereditary Breast Cancer study. In total, 83 BRCA1/2 VUSs (BRCA1, n=26; BRCA2, n=57) were analysed. The multifactorial probability was estimated by combining the prior probability with the overall likelihood ratio derived from co-occurrence of each VUS with pathogenic variants, personal and family history, and tumour characteristics. The classification was compared with the interpretation according to the American College of Medical Genetics and Genomics–Association for Molecular Pathology (ACMG/AMP) guidelines. An external validation was conducted using independent data set of 810 patients.Results We were able to redefine 38 VUSs (BRCA1, n=10; BRCA2, n=28). The revised classification was highly correlated with the ACMG/AMP guideline-based interpretation (BRCA1, p for trend=0.015; BRCA2, p=0.001). Our approach reduced the proportion of VUS from 19% (154/810) to 8.9% (72/810) in the retrospective validation data set.Conclusion The classification in this study would minimise the ‘uncertainty’ in clinical interpretation, and this validated multifactorial model can be used for the reliable annotation of BRCA1/2 VUSs. ER -