Tracking plasma DNA mutation dynamics in estrogen receptor positive metastatic breast cancer with dPCR-SEQ

Detection of ESR1, PIK3CA, and TP53 mutations in plasma ctDNA from ER？+？MBC patients. a Schematic of the dPCR-SEQ workflow for plasma ctDNA analysis. b Summary of plasma ctDNA mutations identified in 31 patients analyzed for the presence of ESR1, PIK3CA, and TP53 mutations by dPCR-SEQ. ESR1 mutations are sub-classified as hotspot or non-hotspot. Some patients had both hotspot and non-hotspot mutations (shown in the shades of red and blue). PIK3CA and TP53 mutations were frequently observed and were consistent with known pathogenic mutations. c Mutant allele frequency and identity of ESR1 coding sequence mutations identified by dPCR-SEQ in patients who were positive by the dPCR ESR1 hotspot mutation assay. d Linear regression analysis of ESR1 hotspot mutation frequency calculated by dPCR and dPCR-SE