Figure 7: Immunohistochemistry for midkine in human neuroblastoma tissue samples. Prechemotherapy and postchemotherapy patient neuroblastoma biopsy samples were collected and stained for midkine. Midkine staining was scored using a 0 (negative), 1+ (weak staining), 2+ (moderate staining), and 3+ (strong staining) scale on a blinded basis. Midkine staining was then correlated with tumor stage, N-MYC amplification status, histology (favorable or unfavorable), and survival. Biopsy scores were also evaluated for a change in midkine staining prechemotherapy to postchemotherapy. Shown here is a sample neuroblastoma histology slide stained for midkine.