Association of morphologic patterns and additional immunophenotypic features in PTCL subtypes classified by the IHC algorithm. (A) Heatmap representation of the morphologic patterns (1-4) and CD4, CD8, TIA-1, granzyme B, and CD30 immunostain and EBER in situ hybridization positivity in PTCL subtypes in training and validation cohort studied on TMA (n = 57). Each case is represented by a column, with CD4/CD8 reported as positive and negative and cytotoxic markers/CD30 positivity graded as 0-3. EBERs was evaluated semiquantitatively calculating the average number of positive cells per field (f): 0/f = 0; <1/f = 1+; 1 to 9/f = 2+; 10 to 50/f = 3+; and >50/f = 4+. Distribution of (B) CD4 and CD8 single-positive, double-positive, or double-negative immunophenotype; (C) cytotoxic markers; (D) CD30; and (E) EBER in the 2 PTCL subtypes. *There is a significant association of cytotoxic marker expression with PTCL-TBX21 subtype (P < .001).