Effect of Crk siRNA on morphology and biological activity of human ovarian cancer cell line MCAS. (A). Membrane ruffling is observed in the control MCAS cells (left panel), and siRNA for Crk suppressed these phenotypes (middle). When Crk is overexpressed, clear ruffling appeared (right, yellow color indicates Crk expression). (B). Control MCAS cells form metastatic nodules in the peritoneal cavity mimicking peritonitis carcinomatosa of human ovarian cancer patients when cells are injected into the peritoneal cavity of nude mice. H&E stain for lymphatic invasion of the peritoneal wall is displayed (left). Crk depleted cells by siRNA lose their malignant potential (right). [See additional file 2] (i) Human synovial sarcoma cell line Fuji with control siRNA was stimulated with HGF. (ii) Human synovial sarcoma cell line Fuji with CRK siRNA was stimulated with HGF. Note that the cells exhibit flat morphology and their movement is static.