Figure 2

Sensitivity of ESR1 enhanced-ice-COLD-PCR assay. Y537S alteration was diluted in wild type DNA to attain mutation fractions ranging from 10% to 0.005%. All dilutions and SW480 cell wild type DNA were subjected to enhanced-ice-COLD-PCR followed by droplet digital PCR analysis. The detected Y537S fractional abundance was enriched 100-fold compared to the initial abundance in templates, allow the detection of the Y537S mutation at a 0.01% dilution (i.e., 1 mutant in 10,000 molecules).