Multimodal spatial profiling reveals distinct myeloid-defined ENKTL subgroups and tumor-myeloid cooperativity within prognostic inflammatory niche.

Extranodal NK/T-cell lymphoma (ENKTL) is an aggressive Epstein-Barr virus (EBV)-associated malignancy with a heterogeneous tumor microenvironment, yet macrophage heterogeneity and tumor-macrophage crosstalk remain poorly defined. Here, we integrate spatial transcriptomic and proteomic profiling with single-cell spatial molecular imaging of ENKTL samples and identify two subgroups defined by distinct macrophage programs. Subgroup 1 is enriched for inflammatory macrophages exhibiting IFN-α/γ responses and immune-regulatory molecules including IDO1 and CD274, whereas Subgroup 2 is immune-quiescent and macrophage-sparse, with its macrophage compartment skewed towards STAB1 macrophages with scavenging features. Notably, an NF-κB-activated and EBV-associated tumor subset is specifically enriched in Subgroup 1, displaying concurrent immunostimulatory and immunoregulatory features that parallel the co-enriched myeloid states and showing reproducible sample-level associations with these myeloid states across datasets. Spatial neighborhood analysis further delineates an inflammation niche where NF-κB tumor cells physically co-localize with these inflammatory macrophages, accompanied by enhanced tumor-myeloid and myeloid-myeloid signaling, implicating a process of tumor-associated myeloid recruitment followed by CCL- and IL1-mediated myeloid self-reinforcement. Critically, higher abundance of this niche correlates with improved survival across independent cohorts, revealing contrasting spatial tumor-immune architectures with prognostic relevance. Together, our study provides a spatially resolved framework for understanding ENKTL biology and guiding immunotherapeutic strategies.