SERPINE1 and cancer: However, when we orthotopically injected the pancreata of immunocompetent mice with the KP cells transduced with either a vector control or an shRNA against Pai-1, we found that the suppression of Pai-1 reduced tumor growth, as shown by the reduced pancreata weight and reduced both cancer cell and stromal fibroblast proliferation (Fig. 4L and fig.