HIF-1α was strongly associated with pathologic differentiation, clinic stage, magnitude of lesions, and patient age, whereas GLUT1 was associated with lymphatic metastasis (P < .05).
Subsequent xenograft generations have conserved immunohistochemical and ultrastructural properties typical for malignant renal epithelium-derived neoplasia (vimentin+, CK-19+, CA IX+ with hypoxia-inducible factor (HIF)-1 alpha constitutive expression) and have demonstrated extensive proliferation, lack of apoptosis, severe genetic alterations, and molecular expression alterations; transforming growth factor beta 1 (TGF-beta 1), hepatocyte growth factor (HGF), proto-oncogene (c-met), matrix metalloproteinase (MMP)-1, and vascular endothelial growth factor (VEGF) C and D were overexpressed, whereas human epidermal growth factor receptor (HER)-2, MMP-2 and MMP-9, VEGF-R3, p53, and p27 were severely down-regulated, suggesting a proangiogenic environment, local invasiveness, and facilitated lymphatic metastasis.