Expression levels of genes that regulate metastasis and angiogenesis correlate with advanced pathological stage of renal cell carcinoma

We examined the expression levels of a number of metastasis-related genes to determine the relationship of these levels to the development of metastasis in renal cell carcinoma. Gene expression was examined in 46 formalin-fixed, paraffin-embedded, archival specimens of primary organ-confined, clear-cell, renal cell carcinoma from patients who had undergone radical nephrectomy. Twenty samples were from patients who did not have metastasis after a median of 48 months; 26 were from patients with either synchronous or metachronous metastases. Microvessel density was assessed by anti-CD-34 immunohistochemical analysis. The expression levels of basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), interleukin-8 (IL-8), matrix metalloproteinases (MMP)-2 and -9, and E-cadherin were examined at the periphery of the tumor by a colorimetric in situ mRNA. The expression levels of bFGF, VEGF, IL-8, MMP-2, and MMP-9 were significantly higher in primary renal tumors from patients with either synchronous or metachronous metastases than those who were disease-free at a median of 48 months of follow-up. Multivariate analysis of diseasefree survival showed that the ratio of MMP-9 to Ecadherin (P=0.012) and the expression level of bFGF expression (P=0.045), were independent predictors for the development of metastases. The expression levels of bFGF, VEGF, and IL-8 did not correlate with microvessel density, which in itself was not a significant predictor of progression (P=0.21). In summary, expression levels of genes that regulate metastasis angiogenesis can predict the metastatic potential in individual patients with organ-confined clear-cell renal carcinoma.