Figure 1.

β-Galactosidase staining in tissues from MMP-9 promoter-reporter mice. All section shown are stained for β-galactosidase activity and counterstained with hematoxylin. A-D: Sections from breast tissue of mice transgenic for MMTV-polyoma middle T and MMP-9 promoter-β-galactosidase. A: A section from a 2-week-old male mouse breast. B: A section from a 2-week-old female mouse. C: A higher power view of a section from an area of in situ carcinoma from a female mouse breast tumor. D: An area of invasive carcinoma from a female breast carcinoma. E-H: Sections of skin. E: Normal untreated skin. F: A section from a papilloma induced by skin carcinogenesis. G: Higher power view of a dysplastic area from a papilloma. H: Invasive squamous cell carcinoma. I: Section from adenocarcinoma that developed spontaneously in the pelvic region of a male mouse.