ADC	antibody–drug conjugate
ADP	poly-adenosine diphosphate
AI	aromatase inhibitor
AON	antisense oligonucleotide
APCL	adenomatous polyposis coli protein-like gene
AR	androgen receptor
ATM	ataxia telangiectasia mutated gene
ATRA	all-trans retinoic acid
BCSC	breast cancer stem cell
BRCA1	breast cancer susceptibility gene 1
BRCA2	breast cancer susceptibility gene 2
CAR-T	chimeric antigen receptor (CAR) T-cell
CSA	Cockayne syndrome group A
CSC	cancer stem cell
CTLA-4	cytotoxic T-lymphocyte-associated antigen 4
DEAB	diethylamino benzaldehyde
DHEAS	dehydroepiandrosterone sulfate
DHT	5α-dihydrotestosterone
DLL-1	Delta-like-1
DLL-3	Delta-like-3
DLL-4	Delta-like-4
EGF	epidermal growth factor
EGFR	epidermal growth factor receptor
EMA	European Medicine Agency
EMT	epithelial-to-mesenchymal transition
ER	estrogen receptor
ER−	ER-negative
ER+	ER-positive
ESR1	estrogen receptor gene
FDA	The United States Food and Drug Administration
GFR	growth factor receptor
GSI	γ-secretase inhibitor
HDACi	histone deacetylase inhibitor
HDAC	histone deacetylase
HER2	human epidermal growth factor receptor 2
HER2−	HER2-negative
HER2+	HER2-positive
Hh	Hedgehog
HR	hormone receptor
HR+	HR-positive
ICI	immune checkpoint inhibitor
iDFS	invasive disease-free survival
IL-6	cytokine interleukin-6
InsR	insulin receptor
JAK	Janus kinase
mBC	advanced or metastatic breast cancer
MMP	matrix metalloproteinase
mTOR	mammalian target of rapamycin
N/A	not applicable
NRARP	Notch-regulated ankyrin repeat protein
OS	overall survival
p110	the catalytic subunit of PI3K
p85	the regulatory subunit of PI3K
PARP	poly-adenosine diphosphate-ribose polymerase
PD-1	programmed cell death-1
PD-L1	programmed cell death ligand-1
PFS	progression-free survival
PI3K	phosphoinositide 3 kinase
PR	progesterone receptor
pRB	retinoblastoma protein
RB	retinoblastoma
RTK	growth factor receptor tyrosine kinase
SFK	Src family kinase
STAT	signal transducers and activators of transcription
TNBC	triple-negative breast cancer
TROP-2	trophoblast cell-surface antigen 2
ZIP9	iron-regulated transporter-like protein 9