Comprehensive Analysis of the Expression and Prognosis for SFRPs in Breast Carcinoma

Secreted frizzled-related proteins (SFRPs) are a group of five secreted glycoproteins—SFRP1, SFRP2, SFRP3 (frizzled related protein, FRZB), SFRP4, and SFRP5—which contain a frizzled-related cysteine-rich domain and a netrin module. We analyzed SFRPs’ expression levels, mutations, regulation, functional networks, and correlation with immune infiltration in breast cancer (BC) patients using data from multiple open databases. SFRP1/3/4/5 were downregulated and SFRP2 was upregulated in BC patients compared to healthy controls. Furthermore, higher levels of SFRP1/3/4 were significantly associated with favorable prognosis. In addition, the prognostic significance of the infiltrating B cells was correlated to the SFRPs. Based on these findings, we hypothesize that SFRPs play a synergistic role in BC progression, and are, therefore, promising prognostic biomarkers as well as therapeutic targets.