Editor's Note:In 2025, the highly anticipated 30th European Hematology Association (EHA) Annual Congress was grandly held in Milan, Italy. This conference brought together top experts and scholars from around the world to discuss cutting-edge topics in basic research and clinical translation in the field of hematolog.Professor Daniel Hartson from the University of Cambridge delivered an insightful presentation on "Deciphering the Genomics of Aggressive Lymphoma." He systematically elaborated on the genetic complexity of Diffuse Large B-cell Lymphoma (DLBCL), shared his team's breakthrough achievements in constructing novel functional genomics models, and emphasized the critical importance of standardized molecular profiling for advancing future clinical research and personalized medicine.

As the most common type of non-Hodgkin lymphoma, the treatment of Diffuse Large B-cell Lymphoma (DLBCL) has seen relatively slow progress over the past two decades. Despite the continuous emergence of targeted drugs in preclinical studies, most large-scale clinical trials have failed to challenge the cornerstone status of the R-CHOP regimen. The recently approved R-Pola-CHP regimen has also offered only a modest survival benefit. At the beginning of his report, Professor Daniel Hartson pointedly remarked: “The fundamental problem we face is the indiscriminate use of these ‘precise’ targeted drugs without a sufficient understanding of the tumor’s biology. Biologically-targeted therapy must precisely target the biology itself.”

[The Genetic Complexity of DLBCL: A Challenge Far Beyond Single-Gene Diseases]

Professor Hartson pointed out that at the genetic level, DLBCL is not a single disease but a complex syndrome composed of multiple diseases. Reviewing several landmark exome sequencing studies, he highlighted the high degree of complexity and heterogeneity in the genetic landscape of DLBCL. “We are not just talking about single gene mutations. There are about 150 recurrently mutated genes in DLBCL, over 1,000 recurrent specific mutation sites, and each patient typically harbors a combination of 5 to 15 driver mutations.” This highly individualized genetic landscape means that nearly every patient’s tumor is unique, posing a significant challenge to understanding mutation function and devising effective treatment strategies.

Although different research teams have identified varying lists of mutated genes, they have collectively revealed a core principle: the genetic mutations in DLBCL are not random. Instead, patients can be clustered into different genetic subtypes based on similar mutation profiles. A large-scale sequencing study by Professor Hartson’s team, involving nearly one thousand patients, independently validated and refined the existing genetic subtyping systems, further confirming the universality and importance of the genetic subtype concept in DLBCL.

Breaking Research Bottlenecks: A Novel Human B-cell Model to Decode Mutation Function

To elucidate the biological significance of thousands of mutation combinations, reliable in vitro models are essential. However, traditional lymphoma cell lines have undergone significant changes due to long-term in vitro culture, while genetically engineered mouse models are limited by high costs, long timelines, and interspecies differences. Professor Hartson shared how his team overcame this challenge. His team successfully developed an innovative primary human germinal center (GC) B-cell in vitro culture and gene-editing system. The core breakthroughs of this system are:

l Simulating the microenvironment: By engineering immortalized follicular dendritic cells that express CD40 ligand and IL-21 to serve as a “feeder layer,” the team successfully mimicked the survival microenvironment for B-cells within lymph nodes, enabling them to proliferate robustly in vitro.

l Efficient gene delivery: To address the difficulty of transducing primary GC-B cells with conventional lentiviruses, the team developed chimeric viral vectors based on the Gibbon Ape Leukemia Virus envelope, increasing the gene transduction efficiency to nearly 100%.

“The establishment of this platform allows us to perform complex genetic manipulations—including gene overexpression, CRISPR knockout, and even precise single-base editing—on normal human B-cells isolated from the tonsils of healthy children,” Professor Hartson explained. Using this system, the team successfully generated “genetically-tailored” human DLBCL models in immunodeficient mice, which showed high histopathological similarity to clinical tumors.

Building on this platform, the team launched an ambitious project: to systematically dissect the function of every hotspot mutation in DLBCL. They constructed an Open Reading Frame (ORF) library containing 1,200 clones and, using competitive fitness screens and single-cell perturbational transcriptomics, successfully mapped the effects of 345 key mutations on cellular fitness, gene expression networks, and signaling pathways. “We can now clearly see that specific mutations, such as activating mutations in GNAI2 and CARD11, confer a stronger competitive advantage to B-cells than their wild-type counterparts, and we can precisely identify the downstream pathways they regulate.”

From Bench to Bedside: The Potential and Challenges of Using Genetic Subtyping to Guide Therapy

Professor Hartson further explored how to translate these basic research findings into clinical practice. Citing the PHOENIX study, which evaluated the efficacy of ibrutinib, he noted that although the study did not meet its primary endpoint in the overall population, a retrospective subgroup analysis revealed that ibrutinib significantly improved survival in patients with the MCD and NOTCH1 genetic subtypes. “This suggests that within many clinical trials deemed ‘failures,’ there might be hidden signals of efficacy for specific subtypes.”

Furthermore, his team’s research into the resistance mechanisms of Polatuzumab (an antibody-drug conjugate targeting CD79B) found that cell-surface sialic acid glycosylation is a key factor affecting drug binding. Through a CRISPR screen, they identified the key genes regulating this pathway and confirmed that inhibiting sialylation could increase cellular sensitivity to Polatuzumab by 10- to 50-fold. Approximately 10% of DLBCL patients have mutations in this pathway and could theoretically be “super-responders” to Polatuzumab. However, Professor Hartson lamented that due to the general lack of comprehensive molecular profiling data in existing clinical trials, these highly promising scientific hypotheses cannot be promptly validated.

The “Tower of Babel” Analogy: Standardized Molecular Profiling is the Path Forward

At the end of his presentation, Professor Hartson aptly used the biblical story of the “Tower of Babel” as an analogy for the current predicament in DLBCL research. “We are like the builders of Babel who failed due to an inability to communicate. In the field of DLBCL, different research centers use different gene sequencing panels and collect different genetic data. This lack of unified standards severely impedes effective dialogue and data integration between basic science and clinical trials.”

He emphasized that standardized, comprehensive molecular profiling data is the “common currency” that connects basic research with clinical practice. He concluded by alluding to the scripture: “If we, as a whole, perform standardized and comprehensive molecular profiling of DLBCL, then nothing we plan to do will be impossible for us.” This resonant call to action pointed the way forward for future research in aggressive lymphoma and deeply resonated with the attendees. Professor Hartson’s research not only provides new tools and perspectives for understanding lymphoma pathogenesis but, more importantly, proposes a highly constructive strategic vision for breaking down research barriers and accelerating the advent of the precision therapy era.