Tumor-Infiltrating Lymphocytes Express Vascular Endothelial Growth Factor in Renal Cell Carcinomas

BACKGROUND: Known influence of the immune system on metastases of renal cell cancer (RCC) has led to the development of several therapeutic approaches for further stimulation of the host immune system by cytokines and the retransfusion of tumor-infiltrating lymphocytes (TIL). Based on observations in human prostate adenocarcinomas and transitional cell carcinomas, we have investigated the presence of TIL in different stages of RCC in correlation to vascular endothelial growth factor (VEGF) expression as a parameter for tumor progression and adverse survival in RCC patients. METHODS: Samples from surgically obtained RCC (n = 28) and benign renal parenchyma (n =10) were snap-frozen and processed by double-immunofluorescence staining with CD4/CD8 and VEGF antibodies. RESULTS: In 20 of 28 RCCs a coexpression of TIL-specific markers CD4 and/or CD8 and VEGF was demonstrated. Control tissues were VEGF-negative and showed only negligible infiltration by CD4- or CD8-positive lymphocytes. CONCLUSION: The results indicate that at least 71% of TIL produce VEGF and may promote tumor progression rather than represent an abortive antitumor response of the host immune system. Copyright 2000 S. Karger GmbH, Freiburg