To evaluate the relationship between ctDNA-based information and ER or HER2 tumor clinical biomarker status, we evaluated the association of each of the 150 adjusted ctDNA-based signatures with either ER clinical status (i.e., positive versus negative) or HER2 status (i.e., positive versus negative) across 177 of 178 samples with a TF ≥3% with known ER and HER2 IHC status from tumor tissue. Here, ESR1 is linked to neoplasm.