The novel SOX11 monoclonal antibody, SOX11-C1, offers improved functionality, such as (i) immunofluorescence-based investigations (ii) improved specificity in IHC-P, enabling more sensitive and specific diagnosis and (iii) flow cytometry-based detection, which is potentially feasible in aspirates from MCL and for detection of circulating tumor cells. The gene discussed is SOX11; the disease is mantle cell lymphoma.