Our goal was thus to investigate the expression status of DUSP22 isoforms in normal lymphocytes and PTCL, the mechanism of second allele silencing in PTCL with 6p25.3 rearrangements, and whether DUSP22 exerted tumor-suppressor properties. The gene discussed is DUSP22; the disease is mature T-cell and NK-cell non-Hodgkin lymphoma.