Ablation of CDK6 and STAT5B rewires T cell developmental dynamics and prevents ALK+ lymphoma formation

Abstract

CDK6 and STAT5B are well-established oncogenic drivers, but their interplay during transformation remains poorly understood. Here, we demonstrate that simultaneous genetic deletion of Cdk6 and Stat5b in an NPM-ALKTg/+ mouse model completely prevents tumor formation. Immature DN2/3 thymocytes are identified as the cellular origin of ALK-driven malignancy. Single-cell transcriptomics reveals a tumor-specific differentiation trajectory that is fully disrupted by combined Cdk6/Stat5b loss, coinciding with a developmental shift. We uncover shared transcriptional targets of CDK6 and STAT5B involved in cell-cycle regulation and apoptosis at the tumor initiation stage. In human ALCL cells, dual deletion of CDK6 and STAT5B induces context-dependent synthetic lethality, exposing a potential therapeutic vulnerability. A transcriptional signature derived from CDK6/STAT5B-dependent tumor initiation genes identifies a high-risk subgroup of ALCL patients with worse survival. Together, these findings establish a molecular link between thymocyte development, the crosstalk of CDK6 and STAT5B, oncogenic signaling, and clinical outcome in ALCL. Although CDK6 and STAT5B are established oncogenic drivers, how they cooperate during lymphoma initiation remains poorly understood. The authors show that combined Cdk6 and Stat5b deletion completely prevents ALK-driven anaplastic large cell lymphoma (ALCL) tumorigenesis, and suggest a prognostic signature linked to poor outcome in ALCL.