This rabbit monoclonal antibody recognizes a protein of 36 kDa, identified as Cyclin D1 antibody (also known as Bcl-1 or PRAD-1). Cyclin D1 antibody is a regulatory subunit of certain protein kinases thought to advance the G1 phase of the cell cycle. Cyclin D1, when used in tandem with CD5, CD10 and CD23 may aid in the diagnosis for mantle cell lymphoma. Studies show that Cyclin D1 is also expressed in invasive breast cancer. Due to the superior technology in the development of this antibody, its binding capacity is superior to mouse monoclonal antibodies and is virtually background free. [EP12] shows some positive staining reaction in B-cell chromic lymphocytic leukemia proliferation not seen with other Cyclin D1 clones.