Several related transcriptional coactivators and corepressors have been described that work in concert with the steroid receptor family to either induce or repress transcription from hormone-responsive elements. This family includes GRIP1 (for GR interacting protein 1), also designated NCoA-2 or TIF-2; SRC-1 (for steroid receptor coactivator-1), also designated NCoA-1; and NCoA-3, also designated RAC3, ACTR, AIB-1 (for amplified in breast cancer) and p/CIP (for p300/CBP/co-integrator protein), which displays elevated expression in estrogen receptor positive ovarian and breast cancers and is required for the transcriptional activation of p300/CBP-dependent transcription factors.