OS of the PTCL subtypes using IHC classification. (A) Significant differences in OS were observed between the PTCL-GATA3 and PTCL-TBX21 subtypes using the IHC algorithm and are comparable to the GEP classification (dotted line) in the training cohort. (B) OS curves in the validation cohort using the IHC algorithm. PTCL-GATA3 was significantly associated with worse prognosis in both cohorts. (C) Distribution (percentage) of IHC-defined subtypes was similar in both cohorts.