Figure 4.

Luminal VWF fibers are associated with melanoma brain metastasis. (A) The ret mouse, characterized by spontaneous melanoma development and BMs. (B) BMs (dashed line) were detected by immunohistochemical staining (n = 40) and ret brains were divided into three groups: Met-free, Peri-Met, and Intra-Met. (C) Wt and ret brain cryosections were stained for VWF and CD31, and (D) the percentage of cerebral vessels containing luminal VWF fibers was calculated (n = 4–6 brains/group). Endothelial cell activation and VWF release was defined by measuring the fractions of VWF in the vessel wall and vessel lumen. (E) Skin vessels and melanoma primary tumor vessels were used as controls for quiescent and activated endothelium, respectively. (F) VWF stored in the vessel wall and in the vessel lumen was quantified (n = 20–117 vessels/group). Ns = not significant, *P < .05, **P < .01, scale bar 50 μm.