SFRP1 and breast cancer: Later in 2012, Mukherjee et al. [27] reported that 67% of breast cancer samples were altered in SFRP1. In the same cohort, 56% of samples were hypermethylated in the SFRP1 promoter region, suggesting once more that the hypermethylation of SFRP1 promoter is responsible for SFRP1 silencing in breast cancer [27].