FOS and diffuse large B-cell lymphoma: Compared with germinal center (GC) B cell (GCB)-DLBCL, the ABC-DLBCL cell lines expressed high levels of AP-1 family members, such as c-Jun, JunB, and JunD, which form hetero-dimer with AP-1 family member-activating transcription factors, including ATF2, ATF3, and ATF7.