OCT2 (POU2F2) is a transcription factor that binds the octamer sequence “ATTTGCAT,” a common recognition sequence in immunoglobulin promoter regions. OCT2 plays a role in B-cell differentiation and is a reliable marker for determining B cell lineage. OCT2 can be used in concert with BOB1 to differentiate nodular lymphocyte-predominant Hodgkin lymphoma, which expresses both, from classical Hodgkin lymphoma, which is negative for at least one of the two markers. In immunohistochemistry of normal tissue, OCT2 has nuclear and cytoplasmic localization in immune cells in secondary lymphoid tissues and bone marrow, with high expression in germinal center B cells. References: Histopathology. 2016 Nov;69(5):775-783, PMID: 27319306; Nucleic Acids Res. 2012 Jan;40 (Database issue):D130-5, PMID: 22121212; Archives of Pathology & Laboratory Medicine. 2008 132:3, 441-461, PMID: 18318586; Proc Natl Acad Sci U S A. 2016 Apr 5;113(14):E2039-46, PMID: 26993806