Stratification of PTCL-NOS cases into 4 microenvironmental signatures. (A) Workflow of transcriptomic analysis using the nCounter system. (B) Heat maps show correlation matrix among genes representing microenvironmental immune cells (left) and T/NK cells (right). The correlation matrix was subjected to unsupervised hierarchical clustering. Gene names (right) and corresponding cell-types (bottom) are shown. (C) Hierarchical clustering of 68 PTCL-NOS cases was performed using indicated gene sets. (D) Dot plots represent the Davies-Bouldin Index for each gene set. A gene signature representing a low index score (eg, B cell) serves as a useful classifier. **P < .01 (Wilcoxon rank-sum test). Mø, macrophage.