Pim-1 is transiently expressed in ECs of the ovary during angiogenesis. Immunofluorescence analysis on frozen ovary sections at ovaries during the follicular phase (FP) and luteic phase (LP) at the time indicated. Endothelial-positive cells were identified by staining with PECAM1 (green) antibody, and specific colocalization was valued by double staining with Pim-1 antibodies (red) as indicated. Colocalization analysis was performed with a confocal microscope. Scale bar, 40 μm.