FKBP4 and breast cancer: The under-expression of the genes NRAS, AKT1, and FKBP4, involved in the estrogen signaling pathway, could prevent the development of mammary tumors in female dogs, since high levels of expression of NRAS and AKT1 are related to carcinogenesis [58], while FKBP4 is related to tumorigenesis, which is why it is common to observe them in hormone-dependent cancers, such as breast and prostate cancer [59].