Vascular endothelial growth factor-C and its receptor VEGFR-3 in the nasalmucosa and in nasopharyngeal tumors

Vascular endothelial growth factors (VEGFs) and their receptors (VEGFRs) ar e important regulators of blood and lymphatic vessel growth and vascular pe rmeability. Both blood and lymphatic vessels of the upper respiratory tract play important roles ill pathological conditions, such as infections and t umors. Here we have studied the expression of VEGF-C and its receptor VEGFR -3 in the upper respiratory system by Northern blot analysis and immunohist ochemistry of human tissues, and in situ mRNA hybridization of developing m ouse embryos and beta-galactosidase staining of mouse embryos having a LncZ marker gene in the VEGFR-3 gene locus, The results demonstrate expression of VEGF-C and VEGFR-3 in the developing and adult nasal respiratory epithel ium and in the nasal vascular plexus, respectively. Unlike in most other ti ssues, ill the nasal mucosa VEGFR-3 is expressed in both blood and lymphati c vessels. Expression of VEGF-C was also detected in nasal and nasopharynge al tumor islands, which were surrounded by VEGFR-3-positive angiogenic bloo d vessels. These results suggest that VEGF-C and VEGFR-3 have a role in the development of the nasal submucosal vascular plexus and in its normal func tion and that they are associated with angiogenesis in nasal and nasopharyn geal tumors.