Table 2.

Detailed description of the detected somatic ESR1 variants

Cohort/sample IDPrimary/metastasisER statusHER2 statusBiopsy siteTranscript changeProtein changeKnown somatic variant (literature)Predicted variant zygosity in tumorEndocrine treatment before biopsy
LM3Metastasis+_Liver1033_1034 insGCT344insCNoClonal homozygousAnastrozole Tamoxifen Exemestane Fulvestrant
EM29Metastasis+a_*Bone1138G>CE380QNoUnknownbAnastrazole
P371Primary_+1507C>TR503WNoSubclonalNone
LM17Metastasis+_Lymph node1609T>AY537NYesSubclonalTamoxifen Exemestane Fulvestrant Letrozole Megestrol
EM43Metastasis+_Lymph node1609T>AY537NYesClonal heterozygousTamoxifen
LM12Metastasis+_Bone1610A>CY537CYesClonal heterozygousTamoxifen Goserelin Anastrozole
EM11Metastasis+_Lung1610A>CY537CYesSubclonalAnastrazole
LM4Metastasis+_Liver1610A>CY537SYesClonal heterozygousTamoxifen Goserelin Letrozole Exemestane Fulvestrant
EM51Metastasis+_Liver1610A>CY537SYesSubclonalTamoxifen
LM19Metastasis+_Liver1613A>GD538GYesClonal homozygousTamoxifen Anastrozole Fulvestrant
LM2Metastasis+_Bone1613A>GD538GYesClonal heterozygousAnastrozole Exemestane Fulvestrant
EM8Metastasis+_Skin1613A>GD538GYesUnknownAnastrazole
  • aInferred (assessed on another specimen from patient).

  • bTumor purity or coverage too low for assessment.