Spatial dynamics of the tumor microenvironment in emerging resistance to targeted therapy in EGFR-mutated NSCLC
Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) provide therapeutic benefit in EGFR mutation-positive non-small cell lung cancer, but some individuals develop early resistance. We performed spatial transcriptomics analysis of pre- and posttreatment tumor samples from the same patients to explore the underlying mechanisms of such early resistance. The proportion and activation of fibroblasts increased in association with the development of early resistance, whereas a distinct tumor cell cluster showed activation of tumor necrosis factor- signaling via the NF-{kappa}B pathway even before treatment. Also in the early resistance sample, specific tumor cell clusters interacted with immune and stromal cells. Immature tertiary lymphoid structures (TLSs) were enriched in the early resistance sample, whereas mature TLSs were observed in the long-term response sample. These findings implicate tumor heterogeneity and an inflammatory tumor microenvironment in early EGFR-TKI resistance, providing insight into potential therapeutic strategies to improve treatment outcomes.