Quantifying Microvessel Density and Biomarker Expression in NPC Tumors

For quantification of microvessel density (MVD) in NPC tumor samples, the number of blood vessels staining positive for CD31 (1:100 dilution, Abcam, Cambridge, MA, USA) was recorded in ten random fields at 200 magnification. The expression of MDK in NPC tumor samples was examined with IHC as previously described [16 (link)]. The antibody was purchased from Abcam (rabbit monoclonal anti-Midkine, Abcam). In situ detection of miR-9 on formalin-fixed paraffin-embedded samples was essentially performed with a miRCURY LNA™ miR-9 detection probe, using an ISH optimization kit (Exiqon, Vedbaek, Denmark) [10 (link)]. A scramble-miR probe (Exiqon) was performed as negative control.