CD28 and adult T-cell leukemia/lymphoma: The ATLL genome is characterized by frequent alterations in the TCR/NF-κB signaling pathway, including gain-of-function mutations in PLCG1, PRKCB, and CARD11, CTLA4::CD28 and ICOS::CD28 fusions, and REL truncation (Figure 3) (62), (63), (64).