Expression of 16 S100 family calcium-binding protein genes was evaluated by PCR in ten human tissue cDNA libraries. Six to 12 S100 genes were expressed in a tissue-specific manner. Then, the expression in the surgically resected renal cell carcinoma (RCC) and a cultured RCC cell line was studied by RT-PCR. Although eight to nine S100 genes were transcribed in the normal kidney library and non-cancerous part of resected kidney tumors, S100A1 and S100A10 genes were not expressed. However, these genes were newly expressed in the RCC lesions (n=7) and the RCC cell line, indicating that expression of S100A1 and S100A10 genes is accompanied by RCC.