Thoughts on Beta-integrins and a postulated pathogenesis for nasopharyngeal carcinoma
The Epstein-Barr virus (EBV) has been definitively implicated in the development of nasopharyngeal cancer (NPC). However, little is known about how specifically EBV gains entry into the cells to effect carcinogenic change, and why this affects certain ethnic populations more than others. The current dogma regarding EBV infection in NPC has been that of late infection, followed by multiple postulated mechanisms for immune evasion of EBV against the host defences, leading to eventual trigger of carcinogenesis. This paper postulates that beta-integrin 6, which is primarily expressed during embryonic development and possibly in neonatal life, may play a role in the development of NPC by facilitating entry of EBV into cells within the nasopharynx during the perinatal period, and this, coupled with ethnic differences in cell—mediated and innate immunity, leads to latent infection within the nasopharynx. Subsequent accumulation of further environmental and/or oncogenic changes leads to the eventual development of NPC in the patient in later life.