Table 1.

Patient cohorts

Patient cohortNo. of specimensAverage number of treatmentsa before biopsy
LM+Metastases from patients with advanced ER+ disease that were heavily pretreated before biopsy (participants in “Personalized Treatment Selection for Metastatic Breast Cancer” trial NCT00780676)257
EM+Metastases from patients with early metastatic ER+ disease511–2
P+Primary ER+ tumors58NA
MMetastases from patients with ER disease11NA
PPrimary ER primary breast cancer disease104NA

Abbreviations: EM+, early metastatic ER+ disease; LM+, late metastatic ER+ breast cancer; M, ER metastatic disease; P+, ER+ primary breast cancer; and P, ER primary breast cancer.

  • aIncluding endocrine treatments and chemotherapy regimens.