Inhibition of PI3K in vitro resulted in decreased proliferation and increased cell death in primary CD4+ PTCL cells harvested from patient lymph nodes, further illustrating the reliance of canine CD4+ PTCL on PI3K/AKT/mTOR signaling for tumor cell proliferation and survival. The gene discussed is CD4; the disease is mature T-cell and NK-cell non-Hodgkin lymphoma.