Using real-time quantitative reverse transcription (RT)-PCR, they noted that SFRP2 was expressed at a significantly higher level in HK-2 cells compared to the RCC cell lines (A-498 and ACHN showed no SFRP2 expression whereas Caki-1 and Caki-2 showed a low expression). Here, SFRP2 is linked to renal cell carcinoma.