Table 1.

PIWI protein expression and function in different cancers.

Piwi Protein	Cancer type	Expression	Function	References
PIWIL1	Gasric	Upregulated	Migration proliferation invasion	[32]
	Mieloma Multiple	Upregulated	Chemoresistance	[30]
	Lung	Upregulated	proliferation migration	[31]
	Breast	Upregulated	DNA methylation	[33]
PIWIL2	Colon Rectal	Uperegulation	Chemoresistance Proliferation	[19,22]
	Gastric	Downregulated	Self renewal properties	[19]
	Ovarian	Upregulated	Apoptosis	[20]
	Breast	Upregulated	Chemoresistance	[19]
PIWIL3	Breast	Upregulated	Proliferation Cell survival	[24]
	Ovarian	Metastasis	Metastasis	[20]
	Mieloma Multiple	Upregulated	Apoptosis	[21]
	Gastric	Upregulated	proliferation migration invasion	[22]
	Glioma	Downregulated	Tumor immune escape	[23]
PIWIL4	Lung	Upregulated	Proliferation	[39]
	Liver	Upregulated	Metastasis	[27]
	Gastric	Upregulated	Apoptosis	[28]
	Testicular	Downpregulated	Proliferation	[29]
	Ovarian	Upregulated	Metastasis	[20]