KDR and neoplasm: However, although several previous reports have shown the potential clinical relevance of these markers, whose expression correlates with the extent of tumour vasculature and aggressiveness, the immunohistochemical expressions of Tie-2/Tek [Kaipainen et al, 1994; Hatva et al, 1995; Salven et al, 1996; Peters et al, 1998) and of VEGF-R1 and VEGF-R2 (Yokoyama et al, 2000; Yao et al, 2001) expression have not been well documented in the literature, with regard to their clinicopathological relevance.