STAT3 and primary cutaneous T-cell non-Hodgkin lymphoma: Incorporating additional diagnosis criteria, such as STAT3/5 copy number gain and STAT3/5 nuclear expression status by immunohistochemistry, could assist in a more accurate classification and subsequent therapeutic intervention of advanced CTCL subtypes, as this was the case with prognostic markers in other mature T‐cell leukemias, such as T‐PLL, PTCL‐NOS, or T‐LGLL (Herling et al, 2004).