Significance

Estrogen receptor α (ERα) is a transcription factor that induces cell proliferation and exhibits increased expression in a large subset of breast cancers. We comprehensively searched for indicators of poor prognosis in ERα-positive breast cancer through the multiple databases, including interactome, transcriptome, and survival analysis, and identified FKBP52. We found that two immunophilins, FKBP52 and FKBP51, have opposing effects on ERα stability and propose that therapeutic targeting of FKBP52 could be useful for the prevention and treatment of ERα-positive breast cancers, including endocrine therapy–resistant breast cancers.