Druggable host gene dependencies in primary effusion lymphoma.

Kaposi's sarcoma-associated herpesvirus (KSHV) causes primary effusion lymphoma (PEL). Here, we review what is known about human gene essentiality in PEL-derived cell lines. We provide an updated list of PEL-specific human gene dependencies, based on the improved definition of core essential genes across human cancer types. The requirements of PEL cell lines for interferon regulatory factor 4 (IRF4), basic leukine zipper ATF-like transcription factor (BATF), G1/S cyclin D2 (CCND2), CASP8 and FADD like apoptosis regulator (CFLAR), MCL1 apoptosis regulator (MCL1), and murine double minute 2 (MDM2) have been confirmed experimentally. KSHV co-opts IRF4 and BATF to drive superenhancer (SE)-mediated expression of IRF4 itself, MYC, and CCND2. IRF4 dependency of SE-mediated gene expression is shared with Epstein-Barr virus-transformed lymphoblastoid cell lines (LCLs) and human T-cell leukemia virus type 1-transformed adult T-cell leukemia/lymphoma (ATLL) cell lines, as well as several B-cell lymphomas of nonviral etiology. LCLs and ATLL cell lines similarly share dependencies on CCND2 and CFLAR with PEL, but also have distinct gene dependencies. Genetic dependencies could be exploited for therapeutic intervention in PEL and other cancers.