We evaluated the vascular staining of FKBP12 in paraffin embedded human and mouse breast tumors using IHC with antibodies to FKBP12, and found that FKBP12 localized to human invasive ductal carcinomas in 8 of 11 tumors; and mouse MMTV-neu breast tumor endothelium in 8 of 8 tumors (Figure S1). Here, FKBP1A is linked to breast neoplasm.