Prohibitin is an evolutionarily conserved protein that has anti-proliferative activity. Prohibitin is a 30 kDa, post-synthetically modified protein found in the inner membrane of mitochondria and on the plasma membrane of B cells. It mediates B cell mutation. Prohibitin Controls cell cycle in both transcriptional and post-translational mechanisms. Prohibitin is a potential tumor suppressor. Prohibitin gene mutations are correlated with the breast cancer development and/or progression in over 80%0f the cell lines analyzed.