To gain further insights into the molecular mechanism by which IL-9 promoted survival of DLBCL cells, we treated LY1 and LY8 cells with IL-9 (80 ng/ml) for 72 h and then we investigated the differential changes in expression of six JAK-STAT downstream regulatory genes, including MYC, BAX [20], p21CIP1, PIM1 [21, 22], BCL2L1 and MCL1 [23]. The gene discussed is CDKN1A; the disease is diffuse large B-cell lymphoma.