Table 1.

PD-L1 subcellular distribution and associated regulatory factors.

Cancer type	Regulatory factor	Exosomal PD-L1	Cell surface PD-L1	Reference
Melanoma	IFN-ɣ	↑	↑	[12]
Melanoma	HRS knockdown	↓	↑	[12]
Melanoma	IFN-α, IFN-ɣ, TNF-α	↑	↑	[29]
Glioblastoma	IFN-ɣ	↑	↑	[15]
BC	ALIX knockdown	↓	↑	[25]
NSCLC	Acquired TKI resistance	↑	↑	[28]
PC	Rab27a knockdown	↓	=	[17]
PC	nSMase2 knockdown	↓	↓	[17]

Subcellular PD-L1 expression includes: ↑ promotion, ↓ inhibition, = unchanged. IFN-γ: interferon-γ; IFN-α: interferon-α; HRS: hepatocyte growth factor-regulated tyrosine kinase substrate; TNF-α: tumor necrosis factor-α; BC: breast cancer; ALIX: ALG-2 interacting protein X; NSCLC: non-small-cell lung cancer; TKI: tyrosine kinase inhibitors; PC: prostate cancer; Rab27a: Ras-related protein 27a; nSMAase2: neutral sphingomyelinase 2.