PSMB9 and Epstein-Barr virus infection: EBV infection of Nasopharyngeal carcinoma (NPC) in the type II latency program, where tumor cells typically express the EBV-encoded proteins of EBNA1, LMP1 and LMP2, all of which play a main role in preserving EBV infection and prompting the rest B lymphocytes persistent hyperplasia [7,8,9,10,11].