Biology as vulnerability in follicular lymphoma: genetics, epigenetics, and immunogenetics

ABSTRACT: Follicular lymphoma (FL) represents a heterogeneous group of B-cell neoplasms with distinct genetic, epigenetic, microenvironmental, and clinical features. It is the most prevalent indolent non-Hodgkin lymphoma, characterized by a relapsing course and risk of transformation to aggressive diffuse large B-cell lymphoma. Recent advances in high-throughput sequencing, spatial transcriptomics, and imaging technologies uncovered genetic, epigenetic, and immunogenetic features underpinning FL, offering insights into its biology and potential therapeutic vulnerabilities. Although FL is primarily driven by the hallmark t(14;18) translocation involving BCL2, its pathogenesis requires additional oncogenic mutations, particularly in genes regulating chromatin and histone modifications. These early genetic and epigenetic alterations promote the persistence and evolution of cancer precursor cells, setting the stage for lymphomagenesis. The tumor microenvironment is also crucial in FL progression and patient prognosis, with T cells, stromal cells, and macrophages playing pivotal roles in facilitating tumor immune escape. Targeted therapies, including B-cell lymphoma 2 (BCL2) inhibitors, epigenetic modulators, and immunotherapies, have emerged from this deeper understanding of FL biology. Achieving a cure for FL will require targeted therapies that selectively eliminate cancer precursor cells with minimal impact on normal cells, thus preventing relapse and avoiding harmful side effects. Eradicating minimal residual disease should be a primary objective rather than waiting for clinical relapse. Future research must prioritize the development of accurate experimental models, the elucidation of FL precursors, and a deeper understanding of its heterogeneity, dependencies, progression, and mechanisms driving transformation. Implementing targeted therapies at FL early stages, instead of the current "watch and wait" approach, will be essential to improve patient outcomes.