Abstract P6-07-20: Allele-specific PCR assay for estrogen receptor (ESR1) mutation detection

Seventy percent of breast cancers are estrogen receptor (ER) positive and, while the majority of these patients initially respond to hormone therapy, approximately 20-30% will become therapy refractory. Recent data suggest activating-mutations in the estrogen receptor gene (ESR1) ligand binding domain (LBD), which are acquired during anti-estrogen treatment and rarely found in primary untreated ER+ breast cancer, are associated with resistance. Some researchers propose that ESR1 mutations are a prognostic and predictive marker, but more studies are needed to assess the clinical utility of the ESR1 mutations. However, current ESR1 mutation detection methods, that is, next generation sequencing and digital PCR, are very labor-intensive, lengthy, and expensive and require special training. To aid research on the diagnostic potential of ESR1 mutations, we developed a prototype allele-specific qPCR assay for the detection of 18 recurrent mutations in the ESR1 LBD. The test is suitable for DNA obtained from FFPE tissue as well cfDNA from plasma. It is sensitive, yet simple, robust and results can be obtained in less than 8 hours. Herein, we demonstrate the analytical performance of our ESR1 mutation detection assay using contrived samples. We are also planning to test clinical FFPET and plasma samples in the future. Citation Format: Litterst CM, Tran HB, Chien S, Chen X, Wen W, Begovich A. Allele-specific PCR assay for estrogen receptor (ESR1) mutation detection [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-07-20.