PLXNB1 and prostate neoplasm: Plexin-B1 was expressed at moderate levels in the epithelial cells of Ptenfl/flKrasG12V prostate tumor cells (Supplementary Fig. S2E, antibody specificity shown in Supplementary Fig. S2F), and expressed at high levels in Ptenfl/flKrasG12VPLXNB1WT (Supplementary Fig. S2G and S2H) and Ptenfl/flKrasG12VPLXNB1P1597L primary tumors and metastases (Supplementary Fig. S2I–S2K).