SFRP2 and renal cell carcinoma: SFRP2 stimulates angiogenesis, is antiapoptotic and has been shown to contribute to tumor growth in breast cancer [16,22,23,24], breast cancer lung metastases [25], angiosarcoma [16], rhabdomyosarcoma [26], alveolar soft part sarcoma [27], malignant glioma [28], multiple myeloma [29], renal cell carcinoma [30], prostate cancer [31], lung cancer [32] and melanoma [33,34].