[Expression and subtype analysis of vascular endothelial growth factor (VEGF) and its receptor (flt-1) in human...

Angiogenesis is very important not only for embryogenesis and wound healing but also for tumor growth in vivo because vessels supply oxygen and nutrition to the tumor mass. In this study, we focused on Vascular Endothelial Growth Factor (VEGF), a newly characterized endothel-specific growth factor and investigated the expression of VEGF in 13 ovarian tumors and 3 normal ovaries by using polymerase chain reaction (PCR) analysis and Northern blot analysis. Further, we examined the expression pattern of 4 alternatively spliced forms of VEGF in these tissues. The level of VEGF mRNA was higher in 77% of ovarian tumors when compared with that in normal ovaries. Among subtypes of VEGF, 121-, 165- and 189-amino acid types were detected but 206-amino acid type was not observed in ovarian tumors. The most abundant form of VEGF was 121-amino acid type and the relative amounts of the various forms of VEGF were 121-amino acid type > 165-amino acid type >> 189-amino acid type. Expression of flt-1, a receptor for VEGF was detectable by PCR but not by Northern blot analysis. These results suggest that like other epithelial cell-derived carcinomas, ovarian tumors use the VEGF/flt-1 system for tumor angiogenesis.