AF	Activation function
AEs	Adverse events
ALT	Alanine aminotransferase
AIs	Aromatase inhibitors
AST	Aspartate aminotransferase
ctDNA	Circulating tumor DNA
CBR	Clinical benefit rate
CDK4/6i	Cyclin-dependent-kinase 4/6 inhibitors
DNA	Deoxynucleic acid
DLT	Dose limiting toxicity
ET	Endocrine therapy
E2	Estradiol
ER	Estrogen receptor
ERE	Estrogen responsive element
ER+	Estrogen receptor-positive
ERK	Extracellular signal regulated kinase
HR	Hormone receptor
HR+	Hormonal receptors-positive
HER2	Human epidermal growth factor receptor 2
LFTs	Liver function tests
LTED	Long-term estrogen-deprived
MTD	Maximum tolerated dose
MBC	Metastatic breast cancer
MAPK	Mitogen-activated protein kinase
ORR	Objective response rate
PR	Partial response
PDX	Patient-derived xenograft
PK	Pharmacokinetics
RP2D	Phase II dose
PI3K	Phosphoinositide 3-kinase
PR+	Progesterone receptor-positive
PFS	Progression-free survival
PD	Progressive disease
AKT	Protein kinase B
PROTAC	Proteolysis targeting chimera
SERCA	Selective estrogen receptor covalent antagonists
SERD	Selective estrogen receptor degraders
SERM	Selective estrogen receptor modulator
SD	Stable disease
SOC	Standard of care
TRAEs	Treatment-emergent adverse events