<unk>  is caused by a combination of factors: viral, environmental influences, and heredity. The viral influence is associated with infection with Epstein-Barr virus (EBV). The Epstein-Barr virus is one of the most common viruses. 95% of all people in the U.S. are exposed to this virus by the time they are 30–40 years old. The World Health Organization does not have set preventative measures for this virus because it is so easily spread and is worldwide. Very rarely does Epstein-Barr virus lead to cancer, which suggests a variety of influencing factors. Other likely causes include genetic susceptibility, consumption of food (in particular salted fish) containing carcinogenic volatile nitrosamines. Various mutations that activate NF-κB signalling have been reported in almost half of<unk>  cases investigated. The association between Epstein-Barr virus and<unk>  is unequivocal in World Health Organization (WHO) types II and III tumors but less well-established for WHO type I (WHO-I)<unk> , where preliminary evaluation has suggested that human papillomavirus (HPV) may be associated. EBV DNA was detectable in the blood plasma samples of 96% of patients with non-keratinizing<unk> , compared with only 7% in controls. The detection of nuclear antigen associated with Epstein-Barr virus (EBNA) and viral DNA in<unk>  type 2 and 3, has revealed that EBV can infect epithelial cells and is associated with their transformation. The cause of<unk>  (particularly the endemic form) seems to follow a multi-step process, in which EBV, ethnic background, and environmental carcinogens all seem to play an important role. More importantly, EBV DNA levels appear to correlate with treatment response and may predict disease recurrence, suggesting that they may be an independent indicator of prognosis. The mechanism by which EBV alters<unk>  cells is being elucidated to provide a rational therapeutic target. It is also being investigated as to whether or not chronic sinusitis could be a potential cause of cancer of the nasopharynx. It is hypothesised that this may happen in a way similar to how chronic inflammatory conditions in other parts of the body, such as esophagitis sometimes leading to Barrett's esophagus because of conditions such as gastroesophageal reflux disease.
Nasopharyngeal carcinoma
Laryngeal cancer
Oropharyngeal cancer
Hypopharyngeal cancer
Adenoiditis
Laryngeal papillomatosis
Nasopharyngeal cyst
Laryngeal cyst