WT1 and neoplasm: We and others have reported that TMS1, 14-3-3sigma and WT1 genes are methylated more frequently in clear cell tumours than in other tumour types (Kaneuchi et al, 2004; Terasawa et al, 2004; Kaneuchi et al, 2005), whereas methylation of SFRP1, 18S and 28S ribosomal DNA genes is more frequently detected in nonclear cell tumours, such as the serous type (Takada et al, 2004; Chan et al, 2005).