LIF-Induced Tumor Plasticity Establishes an Immunosuppressive Myeloid Niche in LKB1-Mutant Lung Cancer.

LKB1 mutations in lung cancer promote an immunosuppressive tumor microenvironment, but the underlying mechanisms remain unknown. Using genetically engineered mouse models and human tumor samples, we demonstrate that LKB1 loss leads to high expression of the cytokine leukemia-inhibitory factor (LIF), which through a cancer cell-autonomous autocrine loop, orchestrates the infiltration of immunosuppressive SiglecFHi neutrophils and Arg1+ interstitial macrophages. Genetic deletion of Lifr, the receptor for LIF, on Lkb1-mutant lung tumors revealed that autocrine LIF signaling induces tumor plasticity and the emergence of a Sox17+ dedifferentiated inflammatory cell state. Antibody-mediated LIF neutralization selectively eliminates the Sox17+ tumor cell state, reduces immunosuppressive myeloid cells, and enhances antitumor T-cell responses. Our study uncovers a novel LKB1-LIF axis driving immune evasion and identifies LIF as a potential therapeutic target in LKB1-mutant lung cancer. This work highlights the interplay between tumor genetics, cellular plasticity, and immune regulation in lung cancer progression. SIGNIFICANCE: LKB1-mutant lung cancers express LIF, which induces an immunosuppressive Sox17+ tumor state. Anti-LIF therapy eliminates this state and restores antitumor immunity, revealing a novel vulnerability in this aggressive cancer subtype lacking effective targeted therapies.