International journal of experimental pathology
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Transgenic mice are important tools for our study of breast cancer pathobiology. In order to evaluate changes in cell phenotype with breast cancer progression, we examined vascular and progenitor cell characteristics in tumours derived from MMTV-PyVmT mice. We performed dual-immunofluorescence staining for Tie2, pTie2Y1100, VEGFR2 and PDGFR-β and the pan-endothelial marker PECAM-1 (CD31) in 39 tumours from MMTV-PyVmT transgenic mice grouped by nuclear grade and tumour morphology. ⋯ We observed a decrease in the average number of Aldh1a1-positive cells in tumours with a non-invasive vs. solid morphology (P=0.03), and in the average number of Aldh1a1-positive mammary tumour cells in low vs. intermediate and low vs. High-nuclear grade tumours (P<0.001). Our findings suggest heterogeneous expression of several molecules important for tumour angiogenesis and tumour progression that are currently under investigation as therapeutic targets for metastatic breast cancer.