CDKN2A and mature T-cell and NK-cell non-Hodgkin lymphoma: On the other hand, in the PTCL-NOS group, p16 positivity was noted in 3/20 (15%) cases, including 1/3 (33.3%) with high expression (score 5–6) and 2/3 (66.7%) with low expression (score 1–4).