To confirm the role of methylation in silencing SMO gene expression, the breast cancer cell line MCF7 that lacked SMO gene expression and the prostate cancer cell line PC3 with moderate SMO expression were treated with 5-aza-dC for 72 h Treatment with 5-aza-dC resulted in the expression of SMO in MCF7 cells, however, treatment with 5-aza-dC decreased SMO expression in PC3 cells (Table 3). Here, SMO is linked to breast cancer.