Both BMP4 and CST6 are metastasis suppression genes downregulated in 231_HM.LNm5 tumour cells relative to non-metastatic 231_ATCC tumour cells (Table 2), and both contain CpG islands spanning their transcription start sites in their 5′ proximal regions (Fig. 6A,D). This evidence concerns the gene BMP4 and neoplasm.