Table 2.

Role of IL-34 in different cancer types.

Cancer type	Function	References
Bone giant cell tumour	IL-34 promotes RANKL-induced osteoclastogenesis	[20]
Mammary cancer	IL-34 enhances M-CSF1-R–dependent macrophage infiltration and promotes tumour growth	[39]
	Lung and brain metastases derived from breast cancer express M-CSF-1 and IL-34	[39]
	Expression of IL-34 is associated with a favourable prognosis in luminal and HER2, but not basal, breast cancer patients	[40]
Human ovarian cancer	High IL-34 expression correlates with worse survival in patients with ovarian cancer	[41]
Hepatocellular carcinoma	IL-34 promotes HCC cell growth and metastasis	[42]
	High IL-34 serum levels associate with poor prognosis in patients with non-viral HCC	[43]
Osteosarcoma	IL-34 enhances osteosarcoma growth and metastasization	[44]
Cholangiocarcinoma	IL-34 promotes stemness features in cancer stem cells	[45]
Lung cancer	IL-34 and M-CSF-1 expression correlates with advanced tumour stages and poor survival in lung cancer patients	[46]
	IL-34 enhances the tumorigenic and immunosuppressive functions of TAMs and promotes the survival of chemoresistant cancer cells	[47]
Multiple myeloma	IL-34 accelerates osteoclast formation increasing the severity of bone lesions	[48]
Sporadic vestibular schwannoma	IL-34 is expressed in sporadic vestibular schwannoma	[49]
Adult T-cell leukemia/lymphoma	IL-34 co-expression with M-CSF-1 may be related to the aggressiveness of this cancer type	[50]
Refractory melanoma	Enhanced expression of IL-34 in refractory melanoma tissues	[51]

RANKL receptor activator of nuclear factor kappa-Β ligand, M-CSF1-R macrophage colony-stimulating factor-1 receptor, HCC hepatocellular carcinoma, TAMs tumour-associated macrophages, M-CSF-1 macrophage colony-stimulating factor-1.