Fig. 1: Omentum as a niche for ovarian cancer metastasis.

a Representation of a naïve unstimulated milky spot and ovarian cancer metastasis activated milky spots within the mouse omentum. The number of macrophages associated with the expanding cancer-immune cells regions increase and cancer cells grow past milky spots into the central adipose region, eventually replacing it. b, c Omental milky spots can be detected in human and mouse samples. IHC of naive omental tissue sections stained for H&E, CD45 and macrophages (mouse F4/80 and human CD68). Uninvolved milky spot in human (b; inset a, b) and mouse (c; inset a). Microscopic ovarian metastases were identified within milky spots in human omenta (b; inset c), and mouse (c; inset b); scale bar = 100 µm. d C57BL/6 mice were injected with ID8 cancer cells and overt (>1 mm) peritoneal metastases over a period of 9 weeks were quantitated for metastatic spread within the abdomen (n = 6). e Representative digital scans of whole mouse omental sections stained for F4/80. Milky spots at week 0 (naive un-injected omentum) and week 1, week 2, week 3, week 4, post injection of ID8 cells. (Bottom) ×40 magnification of milky spot regions at each time point. (Scale bar = 1×, 1000 μM; 40×, 50 μM).