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Purpose Circulating tumor cell (CTC) detection methods based on epithelial cell adhesion molecule (EpCAM) have low detection rates in epithelial ovarian cancer (EOC). Meanwhile, folate receptor alpha (FRα) has high expression in EOC cells. We explored the feasibility of combining FRα and EpCAM as CTC capture targets in EOC. Patients and methods EpCAM and FRα antibodies were linked to magnetic nanospheres (MNs) using the principle of carbodiimide chemistry. Blood samples from healthy donor spiked with A2780 ovarian cancer cells were used for detecting the capture rate. Ninety-five blood samples from 30 patients with EOC were used for comparing the positive rate of detection when using anti-EpCAM-MNs alone with that when using combination of anti-EpCAM-MNs and anti-FRα-MNs. Samples from 28 patients initially diagnosed with EOC and 20 patients with ovarian benign disease were used for evaluating the sensitivity and specificity of combination of anti-EpCAM-MNs and anti-FRα-MNs. Results Regression analysis between the number of recovered and that of spiked A2780 cells revealed yEpCAM = 0.535x (R2 = 0.99), yFRα = 0.901x (R2 = 0.99), and yEpCAM+FRα = 0.928x (R2 = 0.99). In mixtures of A2780 and MCF7 cells, the capture rate was 92% using the combination of anti-EpCAM-MNs and anti-FRα-MNs, exceeding the rate when using anti-EpCAM-MNs or anti-FRα-MNs alone by approximately 20% (P < 0.01). The combination of anti-EpCAM-MNs and anti-FRα-MNs showed a significantly increased positive rate of CTC detection in EOC patients compared with anti-EpCAM-MNs alone (χ2 = 14.45, P < 0.001). Sensitivity values were 0.536 and 0.75 and specificity values were 0.9 and 0.85 when using anti-EpCAM-MNs alone and when using the combination of anti-EpCAM-MNs and anti-FRα-MNs, respectively. Conclusion The combination of FRα and EpCAM is feasible as a CTC capture target of CTC detection in patients with EOC.

Na Li,1 Hao Zuo,1 Luojun Chen,1 Huali Liu,1 Jin Zhou,1 Yi Yao,1 Bin Xu,1 Hongyun Gong,1 Yiming Weng,1 Qinyong Hu,1 Qibin Song,1 Min Peng,1 Yanxiang Cheng2 1Department of Oncology, Renmin Hospital of Wuhan University, Wuhan, Hubei, People’s Republic of China; 2Department of Obstetrics and Gynecology, Renmin Hospital of Wuhan University, Wuhan, Hubei, People’s Republic of ChinaCorrespondence: Min PengDepartment of Oncology, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, People’s Republic of ChinaTel +86 133 1713 3140Email mpeng320@whu.edu.cnYanxiang ChengDepartment of Obstetrics and Gynecology, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, People’s Republic of ChinaTel +86 27 8804 1911Email doctornancy@qq.comPurpose: Circulating tumor cell (CTC) detection methods based on epithelial cell adhesion molecule (EpCAM) have low detection rates in epithelial ovarian cancer (EOC). Meanwhile, folate receptor alpha (FRα) has high expression in EOC cells. We explored the feasibility of combining FRα and EpCAM as CTC capture targets in EOC.Patients and methods: EpCAM and FRα antibodies were linked to magnetic nanospheres (MNs) using the principle of carbodiimide chemistry. Blood samples from healthy donor spiked with A2780 ovarian cancer cells were used for detecting the capture rate. Ninety-five blood samples from 30 patients with EOC were used for comparing the positive rate of detection when using anti-EpCAM-MNs alone with that when using combination of anti-EpCAM-MNs and anti-FRα-MNs. Samples from 28 patients initially diagnosed with EOC and 20 patients with ovarian benign disease were used for evaluating the sensitivity and specificity of combination of anti-EpCAM-MNs and anti-FRα-MNs.Results: Regression analysis between the number of recovered and that of spiked A2780 cells revealed yEpCAM = 0.535x (R2 = 0.99), yFRα = 0.901x (R2 = 0.99), and yEpCAM+FRα = 0.928x (R2 = 0.99). In mixtures of A2780 and MCF7 cells, the capture rate was 92% using the combination of anti-EpCAM-MNs and anti-FRα-MNs, exceeding the rate when using anti-EpCAM-MNs or anti-FRα-MNs alone by approximately 20% (P < 0.01). The combination of anti-EpCAM-MNs and anti-FRα-MNs showed a significantly increased positive rate of CTC detection in EOC patients compared with anti-EpCAM-MNs alone (χ2 = 14.45, P < 0.001). Sensitivity values were 0.536 and 0.75 and specificity values were 0.9 and 0.85 when using anti-EpCAM-MNs alone and when using the combination of anti-EpCAM-MNs and anti-FRα-MNs, respectively.Conclusion: The combination of FRα and EpCAM is feasible as a CTC capture target of CTC detection in patients with EOC.Keywords: circulating tumor cells, ovarian cancer, epithelial cell adhesion molecule, folate receptor alpha