BIRC5 and nasopharyngeal carcinoma: [31], [37] In NPC patients, the over-expression of BIRC5 has been shown to be extensively related to the poor outcome, including advanced clinical stage, tumor stage and lymph node metastasis, and lower 5-year survival. [23], [25] In the present study, however, we did not found any significant associations between the -31C/G polymorphism and the pathological stages of NPC.