These mutations cause cells to grow uncontrollably and continue living after healthy cells would normally die. It is not clear what causes the mutation that causes throat cancer. NPC is a type of cancer that forms in the epithelial lining of the nasopharynx, the area of the upper throat that lies behind the nose. Researchers found that the genetic variation within the human leukocyte antigen (HLA) and the three genes known as TNFRSF19, MDS EVI1 and CDKN2A/2B can significantly influence a person's risk of developing NPC. Throat cancer is also indiscriminate due to the fact that smoking and/or chewing tobacco, excessive drinking, poor dental hygiene, and a poor diet. All of these factors are done through a person’s choice, making them …show more content…
More than 75% of cases are believed to be due to these two factors. Tobacco smoke is one of the main risk factors for head and neck cancer and one of the most carcinogenic compounds in tobacco smoke is acrylonitrile. Acrylonitrile appears to cause DNA damage indirectly by increasing oxidative stress. cigarette smokers have a lifetime increased risk for head and neck cancers that is 5- to 25-fold increased over the general population. The ex-smoker's risk for squamous cell cancer of the head and neck begins to approach the risk in the general population twenty years after smoking cessation. The high prevalence of tobacco and alcohol use worldwide and the high association of these cancers with these substances makes them ideal targets for enhanced cancer prevention. Smokeless tobacco is cause of oral and pharyngeal cancers (oropharyngeal cancer). Cigar smoking is an important risk factor for oral cancers as well. Other potential environmental carcinogens include occupational exposures such as nickel refining, exposure to textile fibers, and woodworking. Use of marijuana, especially while younger, is linked to an increase in squamous-cell carcinoma cases while other studies suggest use is not shown to be associated with oral squamous cell carcinoma, or associated with decreased squamous cell