To further classify PTCL subtypes, TFH-associated markers (CD10, BCL6, PD1/CD279, ICOS, CXCL13) and cytotoxic T-cell markers (TIA-1, granzyme B, perforin) should also be evaluated. The gene discussed is CXCL13; the disease is mature T-cell and NK-cell non-Hodgkin lymphoma.