Most of these can be excluded by features in the clinical presentation, somewhat different morphology (usually with small to intermediate-sized lymphoma cells), different immunophenotype along with lack of CD30 expression, positivity for EBV (NK/T-cell lymphoma and hydroa vacciniforme-like lymphoproliferative disorder), or positivity for HTLV-1 (adult T-cell leukemia/lymphoma). The gene discussed is TNFRSF8; the disease is T-cell non-Hodgkin lymphoma.