Objective:Ovarian cancer (OC) is one of the leading causes of death for female cancer patients.COC166-9 is an OC-specific monoclonal antibody and we have identified immunoglobulin γ-1 heavy chain constant region (IGHG1) as its antigen.We explore the function of IGHG1 in proliferation,apoptosis and motility of OC cells further in this research.Methods:IGHG1 expression in OC specimens was detected through immunohistochemistry.Real-time quantitative polymerase chain reaction (RT-qPCR) or westem blotring assay was used to test IGHG1 expression in OC cells.Viability of OC cells was tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.Flow cytometry or west blotting assay was used to detect cell cycle and apoptosis.Cellular motility was analyzed by using transwell assay and the markers of epithelial-mesenchymal transition (EMT) were tested through immunoblots.Results:Although it exerts negligible effect on the viability and apoptosis of OC cells,IGHG1 could promote migration and invasion of malignant cells in vitro.Mechanistically,IGHG1 increases the expression of N-cadherin and Vimentin while decreases E-cadherin expression.Additionally,IGHG1 expression in OC specimens is higher relative to the paired normal counterparts.Further analysis demonstrates that the increased IGHG1 expression correlates positively with the lymph node metastasis of OC.Conclusions:IGHG1 promotes the motility of OC cells likely through executing the EMT program.Increased IGHG1 expression in OC specimens is associated with the lymph node metastasis.