Vascular endothelial growth factor (VEGF) is a potent inducer of endothelial cell growth and is expressed at elevated levels in several tumor types. In this study immunohistochemical localization and distribution of isoforms of VEGF were examined in malignant and non-malignant human prostatic tissues.

Immunohistochemical localization of VEGF was performed on thirty well, moderately and poorly differentiated stage D₂ prostate cancer specimens and twenty benign prostatic hyperplasia (BPH) specimens. VEGF mRNA was determined by polymerase chain reaction and VEGF protein isoforms were detected by Western blotting of prostate cancer and BPH specimens.

Cytoplasmic immunoreactivity for VEGF was detected in tumor cells and peritumoral stromal cells of prostate cancer specimens and in non-malignant glandular epithelial cells and interglandular stromal cells in BPH specimens. Staining was focal with areas of strongly to weakly stained cells adjacent to negatively staining areas. mRNA's for VEGF₁₂₁, VEGF sub 165 and VEGF₁₈₉ were present in all benign and malignant prostate specimens. VEGF protein isoforms of molecular sizes corresponding to VEGF₁₆₅ and VEGF₁₈₉ were detected in cytosolic extracts of prostate cancers and BPH specimens by Western blotting. In addition, two novel higher molecular weight immunoreactive bands were detected in the prostate specimens.

Widespread distribution of VEGF in prostate cancers and BPH specimens suggest that the VEGF₁₆₅, VEGF₁₈₉ isoforms and novel 90 and 110 kD forms detected may contribute to the establishment or progression of these conditions.