In addition, phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit delta (PIK3CD), mitogen-activated protein kinase kinase kinase 7 (MAP3K7) and mitogen-activated protein kinase kinase 6 (MAP2K6) are downregulated in peripheral T-cell lymphoma during chemotherapy resistance. The gene discussed is MAPK6; the disease is peripheral T-cell lymphoma, not otherwise specified.