To further clarify the role of PRA1 in EBV infected NPC cells, siRNA knockdown of PRA1 was performed to generate PRA1-knockdown NPC clones, which were analyzed by the isobaric mass tags (iTRAQ) labeling approach coupled with 2D LC-MS/MS (Liu et al., 2011). This evidence concerns the gene RABAC1 and nasopharyngeal carcinoma.