Molecular Pathogenesis and Targeted Treatment of Richter Transformation

Area of Science:

• Hematology
• Oncology
• Molecular Biology

Background:

• Richter transformation (RT) is a rare, aggressive complication of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), evolving into diffuse large B-cell lymphoma (DLBCL).
• DLBCL-RT exhibits rapid progression and resistance to conventional chemoimmunotherapy, necessitating novel therapeutic strategies.
• Clonal relatedness is a hallmark of RT, with most cases arising from the antecedent CLL clone, leading to a poorer prognosis.

Purpose of the Study:

• To review current understanding of Richter transformation pathogenesis, including clonal evolution and genetic drivers.
• To explore the immunosuppressive tumor microenvironment in DLBCL-RT and its role in immune evasion.
• To summarize emerging therapeutic strategies for DLBCL-RT, emphasizing personalized and combination approaches.

Main Methods:

• Review of multi-omic data and genetic analyses of RT cases.
• Analysis of the tumor microenvironment, including immune cell populations and checkpoint molecule expression.
• Synthesis of preclinical and clinical data on novel therapeutic agents and approaches.

Main Results:

• RT commonly originates from pre-transformation subclones, representing an early evolutionary trajectory rather than a late event.
• Key genetic lesions (e.g., TP53, CDKN2A/B) and metabolic rewiring (OXPHOS, mTOR) drive transformation and aggressive growth.
• The RT microenvironment is characterized by immunosuppressive cells (Tregs, M2 macrophages) and immune checkpoints (PD-1/PD-L1), facilitating immune escape.

Conclusions:

• RT pathogenesis involves early clonal evolution, specific genetic alterations, and a highly immunosuppressive microenvironment.
• Emerging therapies including targeted agents, bispecific antibodies, and CAR-T cells show promise.
• Biomarker-driven stratification and rational therapeutic combinations are crucial for improving outcomes in DLBCL-RT.