Figure 5: Angiotropism and Serpin B2 in human brain melanoma metastases.

(A) Human brain melanoma metastasis showing striking expression of SERPIN B2 (dark red) by melanoma cells predominately disposed along the abluminal surfaces (angiotropism) of microvascular channels (Asterisks). (B) Montage of mouse brain melanoma spread and metastatic melanoma in the human brain. Lower left image shows GFP-labeled melanoma cells spreading along red lectin-labeled microvascular channels, as shown in the preceding images. Upper right H & E image depicts human melanoma cells disposed along the abluminal surfaces of vascular channels in metastatic melanoma to the brain. The melanoma cells are identified by significant cytoplasmic melanin content and conspicuous cytological atypia. Evidence of intravascular melanoma cells was not identified. Note the conspicuous angiotropism of tumor cells in a pericytic location in both images (green melanoma cells in the murine brain model, melanoma cells containing melanin pigment in the human sample). Scale bars 50 μm.