CCDC50, an essential driver involved in tumorigenesis, is a potential severity marker of diffuse large B cell lymphoma.

Diffuse Large B Cell Lymphoma (DLBCL) is the most common form of blood cancer. Among the subtypes, the activated B-cell (ABC) subtype is typically more aggressive and associated with worse outcomes. However, the underlying mechanisms are not fully understood. In this study, we performed microarray analysis to identify potential ABC-DLBCL-associated genes. We employed Kaplan-Meier methods and cox univariate analysis to explore the prognostic value of the identified candidate gene Coiled-coil domain containing 50 (CCDC50). Additionally, we used DLBCL cell lines and mouse models to explore the functions and mechanisms of CCDC50. Finally, we isolated CCDC50-bearing exosomes from clinical patients to study the correlation between these exosomes and disease severity. Our results demonstrated that CCDC50 not only showed significantly positive correlations with ABC subtype, tumor stage and number of extranodal sites, but also suggested poor outcomes in DLBCL patients. We further found that CCDC50 promoted ABC-DLBCL proliferation in vitro and in vivo. Mechanistically, CCDC50 inhibited ubiquitination-mediated c-Myc degradation by stimulating the PI3K/AKT/GSK-3β pathway. Moreover, CCDC50 expression was positively correlated with c-Myc at protein levels in DLBCL patients. Additionally, in two clinical cohorts, the plasma CCDC50-positive exosomes differentiated DLBCL subtypes robustly (AUC > 0.80) and predicted disease severity effectively (p < 0.05). Our findings suggest that CCDC50 likely drives disease progression in ABC-DLBCL patients, and the CCDC50-bearing exosome holds great potential as a non-invasive biomarker for subtype diagnosis and prognosis prediction of DLBCL patients.