Figure 2. MFP is the endocrine agent that induces the strongest stromal reaction and C4-HD tumor regression.
When C4-HD tumors reached 50 mm2, MPA depot was removed and mice were treated with ICI (5 mg), TAM (5mg/kg/day), MFP or saline (−MPA) for 48 h. +MPA group was sham-operated and treated with saline. A. Top: Final tumor size, % Ki67-positive cells, necrotic and stromal areas were quantified in IHC or H&E. Bottom: H&E staining reveals that C4-HD endocrine-treated tumor displayed tissue remodeling with intense stromal invasion. B. IHC for Ki67 and caspase 3. Arrows indicate that in residual tumor tissue both proliferative (Ki67-positive) and apoptotic (caspase 3-positive) cells were localized to the epithelial edge in contact with the invading stroma. C. Top: Mason's Trichrome (blue: collagen-rich fibrillary stroma; red: parenchymal nuclei) confirmed the composition of regressive stroma. Bottom: IHC for αSMA shows intense signal in the regressive stromal edge facing residual tumor. D. pS6 staining after treatment decreased in C4-HD tumor parenchyma and increased in tumor stroma. Bar 100 μm.