EGFR and VEGFR2 protein expressions in bone metastases of clear cell renal cancer.

BACKGROUND EGFR and VEGFR2 protein expressions are hallmarks of clear cell renal cancer (RCC) with questionable prognostic impact. The skeletal system is one of the most common metastatic sites of RCC. Unfortunately, there are no data for EGFR and VEGFR2 protein expression in such lesions. MATERIALS AND METHODS Twenty cases of bone metastatic clear cell RCC were analyzed. EGFR and VEGFR2 proteins were detected by immunohistochemistry and analyzed by morphometry scoring both % positivity and the intensity. RESULTS EGFR protein scores were significantly reduced in bone metastases of RCC due to the reduction of EGFR protein expression in about one third of the cases (7/20). The VEGFR2 protein-positive phenotype of clear cell RCC was relatively frequent (7/20, 35%), but was lost in bone metastases (2/20, 10%). CONCLUSION These data suggest a phenotypic/genotypic change of clear cell RCC during the progression to bones and warrant further investigation.