Figure 3.

Cutaneous carcinoma invasion and tumor angiogenesis are suppressed in PAI-1^−/− mice. Malignant murine (PDVA) keratinocytes, cultured on a collagen gel in a silicone implantation chamber (top schematic), were transplanted onto PAI-1^−/− and wild-type PAI-1^+/+ mice. Tumor implantation in PAI-1^−/− hosts resulted in a dramatic impairment of stromal invasion and failure to develop a supporting angiogenic network unlike the robust responses evident in wild-type animals. Tissue sections were stained with hematoxylin/eosin (two upper panels) or immunostained for keratin (green; to identify transplanted carcinoma cells) and type IV collagen (red; to delineate capillary vessel basement membrane (two lower panels)).