The analysis showed that the following biological pathways were over-represented in the NPC tissues as compared to the normal tissues : the mitogen-activated protein kinase (MAPK) signaling pathway, the phosphatidylinositol-3 OH kinase/protein kinase B (PI3K-Akt) signaling pathway (Fig. 5a), the apoptotic pathway, and the tumor necrosis factor (TNF) signaling pathway (Fig. 5b). Here, TNF is linked to nasopharyngeal carcinoma.