This is a prospectively designed study. Up to 229 newly diagnosed invasive HER2-positive
or triple-negative breast cancer patients planning neoadjuvant therapy (NAT) will be
enrolled. Blood samples will be collected pre-operatively at the time of diagnosis/prior
to NAT, post-cycle 1/pre-cycle 2 of NAT, after all NAT/immediately before surgery, and
post-operatively at 6, 12, 24, and 36 months, and annually thereafter if funding allows.
Researchers will also collect representative tissue samples from the diagnostic biopsy
(in all participants) and definitive surgery (if available). Additionally, to look at
feasibility of tumor DNA analyses in urine samples, urine samples will be collected along
with blood samples (urine tumor DNA or utDNA).
Next generation sequencing will be performed on core biopsies of all enrolled patients
for tumor-specific mutations (TSM) discovery. Based on those findings, droplet digital
PCR (ddPCR) on plasma DNA samples will also be performed to confirm the presence of the
TSM in the plasma on diagnosis, and one TSM will be chosen to track as the plasma tumor
DNA (ptDNA) mutation of interest. Investigators will perform ddPCR on pre-operative
plasma DNA samples and will assess for the presence of ptDNA. Pathologists will assess
surgical specimens for pathologic response (such as complete response/pCR and residual
cancer burden/RCB). As primary endpoint, investigators will assess the number of patients
with and without preoperative ptDNA who have pCR versus residual disease. As exploratory
endpoints, the following will also be performed: (a) quantitative multiplex
methylation-specific PCR (QM-MSP) in diagnostic biopsy and definitive residual surgery
specimen; and, (b) the circulating methylated tumor DNA (cMethDNA) assay in plasma
specimens (baseline and after NAT), and evaluate associations with pathologic response.
Additional endpoints include the association between plasma and tissue markers at
baseline, after NAT, and (if available) during surveillance with long-term prognosis
(invasive disease-free survival/IDFS and distant disease-free survival/DDFS).