Objective:The mucus production is an indicator for the histological grade of mucinous epithelial ovarian cancer (mEOC).In our previous study,Crk expression was targeted in the human ovarian mucinous adenocarcinoma cell line MCAS through RNA interference,resulting in the establishment of Crk knock down cells.These cells exhibited decreased tumorigenic potential both in vitro and in vivo.The purpose of this study was to investigate if there is any change in the capability of forming mucus in these Crk knock down cells.Methods:Cytoplasmic periodic acid Schiff(PAS)staining and particle excluding assay were conducted to assess the mucus formation within and around cells,respectively.Additionally,the amount of mucus formed in tumor lumps from nude mice model was measured following HE and PAS staining.Results:The increased mucus production in Crk knockdown mEOC cells(MCAS)was manifested by increased number of enlarged cells filled with vacuoles-like mucus observed by phase-contrast microscope and cytoplasmic PAS staining;and enhanced mucus secretion was represented by the assembly of pericellular matrix in particle excluding assay and increased mucus area in tumor lumps from nude mice models.Conclusion:The course of carcinogenesis in mEOC is associated with the altered pattern of mucus production and secretion.The adaptor protein Crk is implicated in both pathways. Objective: The mucus production is an indicator for the histological grade of mucinous epithelial ovarian cancer (mEOC) .In our previous study, Crk expression was targeted in the human ovarian mucinous adenocarcinoma cell line MCAS through RNA interference, resulting in the establishment of Crk knock down cells. The cells were depleted of tumorigenic potential both in vitro and in vivo. The purpose of this study was to investigate if there is any change in the capability of forming mucus in these Crk knock down cells. Methods: Cytoplasmic periodic acid Schiff (PAS ) staining and particle excluding assay were conducted to assess the mucus formation within and around cells, respectively. Additionally, the amount of mucus formed in tumor lumps from nude mice model was followed by HE and PAS staining. Results: The increased mucus production in Crk knockdown mEOC cells (MCAS) was manifested by increased number of enlarged cells filled with vacuoles-like mucus observed by phase-contrast microscope and cytoplasmic PAS staining; and enhanced mucus secretion was represented by the assembly of pericellular matrix in particle excluding assay and increased mucus area in tumor lumps from nude mice models. Contact: The course of carcinogenesis in mEOC is associated with the altered pattern of mucus production and secretion. adapter protein Crk is implicated in both pathways.