Four of the seven genes (SST, PTGS1, ISG15, THY1) were frequently methylated in RCC cell lines (Table 1) but were not methylated in primary RCC (n=20) and although ENG was frequently methylated in RCC cell lines and primary tumours (Table 1), methylation was also detected in adjacent normal tissues and in normal renal tissue from patients without cancer (n=6). This evidence concerns the gene PTGS1 and renal cell carcinoma.