Expression of vascular endothelial growth factor (VEGF) and VEGF receptor Flk-1 in benign, premalignant, and malignant prostate tissue

Vascular endothelial growth factor (VEGF) is one of the most potent mitogen ic, highly specific tumor angiogenic factors, which acts via binding to 2 s pecific tyrosine kinase receptors. There are few studies analyzing VEGF rec eptor expression in prostate cancer cells, and results are contradictory. I n an immunohistochemical study we analyzed VEGF and VEGF receptor fetal liv er kinase (Flk)-1 expression in benign glands, high-grade prostatic intraep ithelial neoplasia (HGPIN), and prostatic carcinomas of different Gleason s cores, obtained from 21 radical prostatectomy specimens. In all benign glan ds, VEGF and Flk-1 expression was confined almost exclusively to the basal cell layer (proliferative cell compartment). In HGPIN, labeling was no long er confined to the basal cell layer but also was seen in all neoplastic sec retory cells. All carcinomas stained positive for both markers. There was a trend for increasing labeling intensity with increasing cellular dediffere ntiation. We concluded that tumor growth stimulated by the VEGF-Flk-1 syste m is promoted not only by neoangiogenesis, but also by tumor cell autostimu lation. The VEGF-Flk-1 system may have an important role in the process of malignant transformation and tumor progression.