Five µm sections of mouse and human tumors were stained with anti-Ki-67 (DAKO), anti-SphK1 (Abcam), anti-SphK1 phospho-Ser225 (ECM Biosciences), anti–CD31 (BD), anti-LYVE-1 (Abcam), or anti-CK8 (Abcam). Sections were examined with a BX-41 light microscope (Olympus) or TCS-SP2 AOBS Confocal Laser Scanning Microscope (Leica) and microvessel density was determined as previously described (29 (link)). ABCB1 and ABCC1 staining in the breast tumors was assessed according to the intensity and population of staining. We scored each sample by 0 to 3: 0 = negative, there is no staining in the tumor cells; 1 = weak, more than 10 % of tumor cells stained with weak intensity; 2 = moderate, more than 30% of tumor cells stained with intermediate intensity or less than 30% of tumor cells stained with strong intensity; 3 = strong, more than 30% of tumor cells stained with strong intensity. Negative: 0 and weak: 1 are considered as low expression, while moderate: 2 and strong: 3 are considered as high expression as previously described (27 (link)).