Frizzled related protein 1, FRP1, FrzA, SARP2, Secreted apoptosis related protein 2, Secreted frizzled related protein 1, SFRP1,
SFRP proteins appear to act as tumor suppressors, with loss of expression or function correlating with many invasive forms of cancer. Deletion of the corresponding SFRP1 gene and promoter hypermethylation leading to gene silencing has been reported in a number of cancers. Abnormal expression of SRFP1 and other Wnt signaling proteins is associated with some cases of retinitis pigmentosa.