Classical Hodgkin Lymphoma (cHL) is one of the most common cancers in young adults. While chemo-radiotherapy is effective, many patients continue to die of cHL or to suffer long-term treatment toxicities, such that more effective and less toxic drugs are needed. Studying the mechanisms underlying the puzzling biology of cHL (the only B cell-derived lymphoma loosing its B-cell identity) should illuminate its pathogenesis and possibly aid in developing better therapeutic strategies. In this project, I will study the function of mutations in the DNA binding domain of the STAT6 transcription factor, which the host laboratory identified as one of the most frequent genetic lesions in cHL. I will perform genome-wide ChIP- and RNA-seq studies to uncover aberrant gene expression regulation and occupancy by mutant versus wild-type STAT6 in cHL versus non-Hodgkin lymphoma (NHL) cell lines, and investigate their functional consequences at the cellular level. I will then express mutant STAT6 in germinal center (GC) B cells, the cHL cell of origin, to evaluate their role in early lymphomagenesis. Because genes mutated in cHL greatly overlap with those altered in NHLs, from which cHL is strikingly different, I will also explore whether unidentified mutations in non-coding regulatory regions may underlie the peculiar cHL pathogenesis. Recurrent somatic non-coding mutations will be identified through whole-genome sequencing of primary cases and will be annotated to the non-coding elements specifically active in cHL cell lines, which I will identify through RNA- and ChIP-seq for key histone marks. Finally, I will use appropriate techniques (e.g. genome topology and CRISPR editing) to assess how such mutations may alter regulatory networks important for cHL biology and identity. The project will also expand my expertise in genomic regulation in lymphomas, boost my research productivity after a career break, and support my transition to an independent investigator.