Fig. 1

Round vimentin-positive cells (arrows) with diameters of 10–15 μm, which were released from the ovarian surface epithelium (OSE). Round cells, which were slightly positive for vimentin, expressed big nuclei and were being released from the epithelium (a, b). After release from OSE, these round cells became strongly positive for vimentin (c, d). Some of them still had some cytoplasmic residual after release and were connected (d). Typical clusters formed from round cells, which released from OSE and were positively-stained for vimentin and embedded by a kind of matrix (e–h). (Inverted microscope: a–c, e–h, magnifications 100x and 200x; light microscope: d, magnification: 400x) Legend: brown-vimentin positivity and blue-nuclei after HE staining. Red Bar: 10 μm for a-c and 100 μm for d–h