Table 1.

The rates of ESR1 mutations in primary tumors, cfDNA, brain and bone metastases from breast cancer patients

ESR1 mutations
SamplesNER+ primaryK303RS463PY537CY537NY537SD538GPts with ESR1 mutationRates of ESR1 mutation
Primary tumor434300000337.0% (3/43)
Bone metastases1211a00000118.3% (1/12)
(9.1% in ER+)c
Brain metastases3824a0000133b7.9% (3/38)
(12.5% in ER+)c
cfDNA2929a0010267b24.1% (7/29)
  • aNumber with known ER+ primary tumor at time of diagnosis (ER status of primary tumor unknown for remaining samples).

  • bOne patient with a brain metastasis, and one with cfDNA analysis had multiple distinct ESR1 mutations within a single sample (polyclonal ESR1 mutations).

  • cFrequency of mutations in metastases from a known ER+ primary tumor.