Abbreviation	Meaning
Alt-NHEJ	Alternative non-homologous end joining
ALT	Alternative lengthening of telomeres
ALT+	ALT pathway-positive
ATRX	Alpha-thalassemia/mental retardation X-linked chromatin remodeler
APB	ALT -associated PML body
APBs	ALT-associated PML bodies
BIR	Break-induced replication
BTR	BLM-TOP3α-RMI1-RMI2
c-NHEJ	Classical non-homologous end joining
CST	CTC1-STN1-TEN1
DAXX	Death domain-associated protein
DDR	DNA damage response
DSBs	Double-strand breaks
D-loop	DNA displacement loop
ECTRs	Extrachromosomal telomeric repeats
HJ	Holliday junction
HP1α	Heterochromatin protein 1
HR	Homologous recombination
I-loops	Internal loops
KAP1	KRAB-associated protein 1
LLPS	Liquid–liquid phase separation
MiDAS	Mitotic DNA synthesis
PARP	Poly (ADP-ribose) polymerase
PCNA	Proliferating cell nuclear antigen
PML	Promyelocytic leukemia
RFC	Replication factor C
SIM	SUMO-interacting motif
SMX	SLX1-SLX4, MUS81-EME1, and XPF-ERCC1
ssDNA	Single-strand DNA
T-circle	Telomere circle
TERC	Telomerase RNA component
TERRA	Telomeric repeats containing RNA