Primary cytotoxic T-cell lymphomas harbor recurrent targetable alterations in the JAK-STAT pathway

Primary cytotoxic T cell lymphomas (CTCLs) are a rare subset of aggressive, poor-prognosis T-cell lymphomas targeting the skin; they include primary cutaneous γδT-cell lymphoma, primary cutaneous VD8+ aggressive epidermotropic T cell lymphoma (PCAETCL), and cytotoxic CTCL not otherwise specified. Lee et al report that all 3 subsets have JAK-STAT activation, but PCAETCL uniquely carries JAK2 gene fusions that may render them especially susceptible to JAK inhibitors.