Expression of vascular endothelial growth factor isoforms and platelet-derived endothelial cell growth factor in bladder cancer

We analyzed the expression of vascular endothelial growth factor (VEGF) messenger ribonucleic acid (mRNA) isoforms and platelet-derived endothelial cell growth factor (PDECGF) mRNA in bladder cancer. We also attempted to determine if correlation exists between their expression level and conventional clinical variables in patients with bladder cancer. Tissues obtained from 60 patients with bladder carcinoma were used for analysis. Expression levels of VEGF isoforms and PDECGF were examined using reverse transcription-polymerase chain reaction (RT-PCR). Correlations between the expression levels of each VEGF isoform and PDECGF and histopathologic findings were evaluated. Four VEGF isoforms corresponding to VEGF121. 165, 189. and 206 were detected in bladder cancer tissue by RT-PCR. Gene expression of all VEGF isoforms as a ratio of the target to glyceraldehyde 3-phosphate dehydrogenase (GAPDH) showed no correlation with pathologic stage of bladder cancer. However, with regard to relative expression levels of VEGF isoform, which is the ratio to the sum of total VEGF isoforms. the levels of VEGF206 and VEGF189 in tumor samples of grade pT2 or higher were significantly lower than those in tumors of grade pT1 or lower (P<.05). In contrast, the levels of VEGF121 in <greater than or equal to>pT2 tumors tended to be higher than those in less than or equal to pT1 tumors (P=.056). The expression level of PDECGF as a ratio to GAPDH in pT2 less than or equal to tumors was significantly higher than that in either pTa or pT1 tumors (P<.05). Moreover. a higher expression level of PDECGF was observed in G3 tumors than in G1 tumors (P<.05). The results indicated that gene expression of VEGF isoforms do not play a significant role in tumor progression or invasion; however, the distribution of VEGF isoforms may play a role in tumor progression of bladder cancer. A high expression level of PDECGF correlated significantly with the tumor progression of bladder cancer. (C) 2000 Elsevier Science Inc. All rights reserved.