CD30 expression is highest on Reed–Sternberg cells and in systemic anaplastic large-cell lymphoma (sALCL), whereas it is lower and more variable in other lymphoma subtypes, including peripheral and cutaneous T-cell lymphomas (PTCL and CTCL). This evidence concerns the gene TNFRSF8 and mature T-cell and NK-cell non-Hodgkin lymphoma.