One study identified CTLA-4/CD28 fusion genes in 58% of AITLs, 23% of PTCL-NOS, and 29% of ENKTLs by reverse transcription-polymerase chain reaction and Sanger sequencing (Yoo et al., 2016). Here, CTLA4 is linked to mature T-cell and NK-cell non-Hodgkin lymphoma.