Abstract 3315: Unveiling a protective role of B-cells in classical Hodgkin lymphoma progression through gene expression signatures

Background: Classical Hodgkin Lymphoma (cHL) is considered highly curable, but identifying patients at risk of relapse or progression after initial treatment remains a challenge. Disease progression may involve biological factors not accounted for by current prognostic models, which could potentially be revealed by molecular analysis. In this study, we performed comprehensive gene expression profiling to identify molecular markers that could help to develop new prognostic tools in cHL patients. Patients and Methods: We conducted a retrospective review of local clinical records to identify patients with confirmed cHL diagnosed between 2004 and 2019, aged 18-65, at any disease stage, and treated with systemic chemotherapy. Gene expression analysis using nCounter Nanostring Technology with the PanCancer Immune Profiling Panel was performed on baseline diagnostic biopsies. Genomic data were correlated with clinical, laboratory, and radiomic information. Progression-Free Survival (PFS) was the primary endpoint. Immunohistochemistry was used for validation. Results: We identified 185 patients with classical Hodgkin lymphoma (cHL), of whom 155 had available formalin-fixed paraffin-embedded (FFPE) tissue samples. Of these, 32% were aged over 45 years, 46% had stage III-IV disease, and 10% presented with bulky disease. After a median follow-up of 72 months (range, 6-171 months), 31 PFS events occurred, with a 4-year PFS rate of 80.4% (95% CI 74.1-87.3). Through Cox Proportional Hazards modeling, we identified 66 genes that were significantly associated with PFS (p<0.05). Of these, 41 genes were positively associated with better PFS, suggesting a protective effect, while 25 genes were linked to a reduced probability of survival. Through correlation analysis and gene ontology, we were able to identify a 7-gene signature associated with B-cell signaling pathways. An unsupervised analysis on the entire cohort based on the expression of the identified B cell signature has allowed us to define two main patient clusters: low- B cell and high- B cell. The former cluster displayed a significant increase in the incidence of clinical events (p=0.03) and worse PFS compared to the high B-cell cluster (p=0.007). Additionally, elevated expression of PAX5, a key regulator of B-cell differentiation, was significantly associated with better PFS, with a 4-year PFS rate of 90% (95% CI 82.7-97.3) compared to 71% (95% CI 61.3-82.4) in patients with lower expression levels. Immunohistochemical evaluation of PAX5 in the tumor microenvironment further supported its potential as a prognostic marker. Conclusion: These results suggest that gene expression analysis may assist in the early detection of disease relapse and highlight the immune-modulatory role of B-cells in cHL progression. Citation Format: Stefano Pozzi, Francesca Reggiani, Tanja Lazic, Nizzoli Maria Elena, Alberto Bavieri, Benedetta Donati, Durmo Rexhep, Riccardo Valli, Attilio Gennaro, Cristian Ascione, Alessia Ruffini, Annibale Versari, Francesco Merli, Massimo Dominici, Alessia Ciarrocchi, Stefano Luminari. Unveiling a protective role of B-cells in classical Hodgkin lymphoma progression through gene expression signatures [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 3315.