Pancreatic tumor growth is increased in the absence of host SPARC. A) 5 ×105 murine pancreatic adenocarcinoma (PAN02) cells were injected orthotopically into wild-type (WT, n=9) and SPARC-/- (SPARC-/-, n=5) mice. The mice were sacrificed 28 days after tumor cell injection and the weight (g) of the entire pancreas including tumor was determined. The mean pancreas weight +/- SEM for WT and SPARC-/- mice are displayed. *, p<0.01. B) Orthotopic and subcutaneous PAN02 tumors from WT and SPARC-/- mice were harvested, fixed in methyl Carnoys or formalin, respectively, sectioned and evaluated for MMP9 expression by immunohistochemistry. MMP9 levels (green) in subcutaneous tumors were developed with FITC-conjugated secondary antibody and sections counterstained with DAPI to identify nuclei (blue). Arrows indicate cells positive for MMP9. MMP9 levels in orthotopic tumors were developed with a peroxidase-conjugated secondary antibody with subsequent reaction with the chromagen DAB. MMP9 positive cells were hand counted in a minimum of 10 fields/group to be 53.0 +/- 14.7 and 33.8 +/- 5.0 in WT and SPARC-/- mice, respectively (p<0.05). Total magnification is 400×.