Table 1.

Markers of OCSCs—function, correlation to clinicopathological features and their cell/tissue origin.

Marker	Function	Origin of Studied Cells	Reference	Association to Clinicopathological Features	Cell/Tissue Origin	Reference
CD44+	Increased tumorigenicity, sphere-formation, cells self-renewal	Primary EOC tumors, cell cultures	[49,50,51,52]	Number of CD44+ cells higher in early stage EOC and correlated with shorter PFS Expression correlated with high-grade, advanced (III/IV FIGO) EOC in younger (<60) patients Higher number of CD44+ cells correlated with chemoresistance and shorter DFI CD44+ correlated with Ki67 index, p53 positivity and tumor grade in HGSOC, mucinous and endometroid EOC	EOC-isolated cells Recurrent EOC (88% HGSOC) Primary and recurrent EOC (78% HGSOC) EOC (HGSOC 62%) and BOT	[105,139,140,141]
CD44 v6+	Increased tumorigenicity, recapitulation of tumors	Xenotransplantation model	[57]	Distant metastases more frequent and metastasis free survival shorter in CD44v6+—high group of patients Increased number of CD44v6+ cells in primary tumors correlated with shorter OS	EOC FIGO I–III tumors EOC FIGO III–IV tumors (71% HGSOC)	[56,57]
CD44+/MyD88+	Increased tumorigenicity, sphere-formation, resistance to apoptosis, chemoresistance	Cell lines, ascites	[142]	Expression of MyD88 protein was an unfavorable prognostic factor for EOC patients	Benign ovarian tumors, BOT and EOC (54% HGSOC)	[97]
CD44+/CD117+	Increased tumorigenicity, sphere-formation, recapitulation of tumors, chemoresistance	EOC tumors, xenograft models	[49]	CD44+CD117+ cell lines were less prone to paclitaxel-induced apoptosis	EOC cell lines	[142]
CD44+/CD24-	Increased tumorigenicity, sphere-formation	Cell lines	[143]	>25% CD44+/CD24- cells in ascites correlated with higher risk of recurrence and shorter PFS	Ascites-isolated cells from advanced EOC	[104]
CD44+/CD24+/ EpCAM+	Increased tumorigenicity, chemoresistance	Cell lines, EOC-isolated cell lines, ascites	[100,110]	Ovarian cancer stem cells expressing EpCAM+ are less prone to chemotherapy and are a source of recurrent tumor after the treatment	EOC I-IV FIGO stage (45% HGSOC, 14% clear cell, 17% endometroid, 12% mucinous)	[100]
CD44+/CD166+	Increased tumorigenicity, sphere-formation	Cell lines	[108]	Population of platinum-resistant cells is enriched in CD44+/CD166+ population	EOC-isolated and standard cell lines	[144]
CD44+ALDH1+	Increased tumorigenicity, chemoresistance	Cell lines	[145]	>50% ALDH1+ cells correlated with shorter OS	Advanced EOC (73% HGSOC)	[145]
CD44+/CD133+/ALDH1A1+	Chemoresistance	Cell lines, EOC-isolated cell lines	[116]	Expression of markers increased in recurrent compared to primary tumors	Advanced primary and recurrent EOC	[116]
CD133+	Increased tumorigenicity, enhanced vasculogenesis	Cell lines, EOC tumors, xenograft models, ascites	[72,78,81,146]	Expression of CD133+ correlated with presence of HGSOC, higher FIGO stage, ascites, chemoresistance, shorter PFS and OS No correlation with prognosis Expression of CD133+ correlated with shorter PFS and OS Expression of CD133+ correlated with shorter OS and platinum chemo-resistance	EOC (67% HGSOC) EOC FIGO III–IV (72% HGSOC) Advanced metastatic HGSOC Advanced primary HGSOC	[73,147,148,149]
CD133+/ALDH1A+	Increased tumorigenicity, cells self-renewal, chemoresistance	EOC tumors, cell lines, xenograft models	[80,81]	Expression of CD133+ correlated with III/IV FIGO stage, expression of CD133+/ALDH1A+ correlated with shorter PFS and OS	HGSOC	[150]
CD117+	Increased tumorigenicity, sphere-formation, recapitulation of tumors, chemoresistance	EOC-isolated cell lines, xenograft model, ascites	[62,63,64,151,152]	Expression of CD117+ correlated with shorter PFS 40% of HGSOC were CD117+ and expression correlated with chemoresistance	Advanced metastatic HGSOC HGSOC	[63,148]
CD24+	Increased tumorigenicity, stimulation of EMT	Cell lines	[92]	Expression of CD24+ correlated with FIG stage and the presence of peritoneal and lymph node metastases	27% HGSOC 12% mucinous 18% clear-cell 18% endometaroid 23% others	[92]

BOT—borderline ovarian tumor; DFI—disease-free interval; EMT—epithelial-mesenchymal transition; EOC—epithelial ovarian cancer; FIGO—International Federation of Obstetrics and Gynecology; HGSOC—high-grade serous ovarian cancer; OS—overall survival; PFS—progression-free survival.