It was found that BMP4 (bone morphogenetic protein 4), an epigenetically regulated gene, was substantially expressed in cisplatin-resistant cell lines; also, BMP4 promoter methylation levels were shown to be inversely linked to BMP4 expression in primary tumors, and patients with high BMP4-expressing tumors had a much worse prognosis; therapeutically, genetic suppression of BMP4 resulted in considerable cisplatin sensitivity of GC cells. This evidence concerns the gene BMP4 and gastric cancer.