POU domain class 2-associating factor 1 (POU2AF1, BOB1) is a nuclear transcriptional factor protein that associates with OCT1 or OCT2. It is necessary for the B-cell antigen response and for germinal center formation. It is also associated with susceptibility to lymphoma. POU2AF1 is expressed in B cells and in lymphomas and also potentially in respiratory epithelium. POU2AF1 antibodies are used to identify B cells in germinal centers, mantle cells, and lymphomas; to determine the lineage of CD20-negative B-cell neoplasms; and to distinguish classical Hodgkin lymphoma from primary mediastinal large B-cell lymphoma. In normal tissues, it is expressed in B-lymphocytes, particularly within germinal centers and mantle cells of lymphoid follicles. It is useful for the identification of B-cell lymphomas and lymphocyte predominant Hodgkins lymphomas. References: Am J Clin Pathol. 2006;126(6):916-924. doi: 10.1309/UJUL60UPUP3YJE93; Histopathology. 2016;69(5):775-783. doi: 10.1111/his.13017; Histopathology. 2010;56(2):217-228. doi: 10.1111/j.1365-2559.2009.03462.x; Am J Clin Pathol. 2006;126(4):534-544. doi: 10.1309/3WG32YRAMQ7RB9D4; Mol Carcinog 2017;56(8):1945-1952. doi: 10.1002/mc.22652; J Immunol. 2016;196(7):3159-3167. doi: 10.4049/jimmunol.1502400; Mod Path 2006 19:1010