The FK506 binding protein 51 (FKBP51) is a ubiquitously expressed immunophilin, encoded by the gene FKBP5, and whose function has been investigated in association with numerous biological processes describing FKBP51 as a central regulator of pathways involved in psychiatric and neurodegenerative disorders, immune response, inflammation, cardiovascular diseases, metabolic pathways, and cancer [1,2,3,4,5]. The gene discussed is FKBP5; the disease is cancer.