Recognizes a protein of ~47kDa, identified as SOX11. This MAb is highly specific and does not cross-react with other members of the SOX-family. Mantle cell lymphoma (MCL) accounts for 5% to 10% of mature B-cell neoplasms and is an aggressive disease genetically characterized by overexpression of Cyclin D1. Cyclin D1 overexpression is the hallmark of MCL. However, approximately 5%-10% of MCLs lack Cyclin D1 expression and may be misdiagnosed. Almost all Cyclin D1-positive as well as Cyclin D1-negative MCL, show overexpression of SOX-11. The detection of this transcription factor is a useful biomarker for identifying true cyclin D1-negative MCL.