Discrete genetic subtypes and tumor microenvironment signatures correlate with peripheral T-cell lymphoma outcomes

Peripheral T-cell lymphoma (PTCL) exhibits a diverse clinical spectrum, necessitating methods to categorize patients based on genomic abnormalities or tumor microenvironment (TME) profiles. We conducted an integrative multiomics study in 129 PTCL patients, performing whole-exome sequencing and identifying three genetic subtypes: C1, C2, and C3. C2 was characterized by loss of tumor suppressor genes and chromosomal instability, while C1 and C3 shared T follicular helper (TFH)-related genomic alterations, with C3 also showing a high incidence of IDH2 mutations and chromosome 5 gain. Compared to C1, survival was significantly worse in C2 (HR 2.52; 95% CI, 1.37-4.63) and C3 (HR 2.14; 95% CI, 1.17-3.89). We also estimated the proportions of immune cell fractions from the bulk RNA sequencing data using CIBERSORTx and classified TME signatures into the following hierarchical clusters: TME1 (characterized by increased B and TFH cells), TME2 (macrophages), and TME3 (activated mast cells). TME2 was associated with shorter survival (HR 3.4; 95% CI, 1.6-7.5) and was more frequent in C2 (64.3%) than in C1 (7.7%), whereas C1 had more TME3 signatures (80.8% vs. 28.6%). These findings highlight a significant relationship between genetic subtypes and TME signatures in PTCL, with important implications for clinical prognosis.