The ZBTB family of proteins is comprised of diverse zinc finger proteins that also contain a BTB (BR-C, ttk and bab) domain. ZBTB7A, also known as LRF, was initially identified as a potential target of the LAZ-3/BCL-6 oncogene. Later reports demonstrated that it could bind to the wild-type IST (inducer of short transcripts) elements of HIV-1 long terminal repeats (LTRs) and stimulate Tat activity on the HIV-1 LTR. More recently it ZBTB7A has been recognized as a proto-oncogene whose overexpression contributes to malignancy in breast cancer and functions as a co-repressor of the androgen receptor in prostate cancer cells.