Objective Defect in apoptosis plays an important role on lymphoma progression.Cellular FLICE inhibitory protein (c-FLIP) is a key inducer of resistance to extrinsic apoptosis.Methods c-FLIP expression was measured by quantitative RT-PCR in 61 patients with peripheral T-cell lymphomas (PTCLs) and correlated with clinical parameters.Biological behavior related to c-FLIP and key cellular signaling pathways involved were further evaluated in T-lymphoma cell lines Jurkat and H9 and xenograft model established with subcuteneous injection of Jurkat cells.