MMP13 in PyMT Tumor Fibroblast Figure 5. Vascularization of MMTV-PyMT tumors is not affected by MMP13. (A) Maximum intensity projections of confocal image stacks from tumor sections showing cell nuclei (red, propidium iodide stained) and vasculature (green, with FITC-conjugated lycopersicon esculentum lectin). (B) No significant differences were observed in vessel diameter (p = 0.95), length (p = 0.4) or volume (p = 0.4) when comparing vessels in tumors from MMTV-PyMT;Mmp13+/+ (n = 9) and MMTV-PyMT;Mmp132/2 mice (n = 9, t-tests). All analyses were done blindly. (C) Morphometric analysis of the proliferation rate in the MMTV-PyMT tumors. Representative immunohistochemical staining for BrdU in an MMTV-PyMT tumor with counting frames applied to the tissue sections (left). Tumor cell proliferation was determined by an observer unaware of the genotypes in one #1–3 gland and one #4 gland tumor from each mouse. MMTV-PyMT;Mmp13+/+, n = 8 and n = 11 at 8 and 11 weeks, respectively, MMTV-PyMT;Mmp132/2, n = 7 and n = 12 at 8 and 11 weeks, respectively (three samples were excluded due to poor morphology). The proliferation rates are shown as the percentage of the total number of neoplastic cells with medians 50% (box) and 95% inclusion intervals (right). doi:10.1371/journal.pone.0002959.g005 PLoS ONE | www.plosone.org 7 August 2008 | Volume 3 | Issue 8 | e2959