Our data, in combination with the results of previous studies, suggest that the tumor-suppressive function of PD-1 signaling in T cell lymphoma may be not restricted to PRKCQ amplification and may be applicable in other patients with oncogenic TCR activation, although the intracellular pathways that mediate PD-1 function in lymphoma cells are inadequately defined and it is still unknown whether PD-1 expression on malignant T cells is a direct result of T cell oncogenesis. This evidence concerns the gene PDCD1 and lymphoma.