Do we know what causes laryngeal and hypopharyngeal cancers?
We don’t know what causes each case of laryngeal or hypopharyngeal cancer. But we do know many of the risk factors for these cancers (see “What are the risk factors for laryngeal and hypopharyngeal cancers?”) and how some of them cause cells to become cancerous.
Scientists believe that some risk factors, such as tobacco or heavy alcohol use, may cause these cancers by damaging the DNA of the cells that line the inside of the larynx and hypopharynx.
DNA is the chemical in each of our cells that makes up our genes — the instructions for how our cells function. We usually look like our parents because they are the source of our DNA. But DNA affects more than how we look. Some genes have instructions for controlling when cells grow and divide into new cells. Genes that help cells grow and divide are called oncogenes. Genes that slow down cell division or cause cells to die at the right time are called tumor suppressor genes. Cancers can be caused by DNA changes that turn on oncogenes or turn off tumor suppressor genes.
Some people inherit DNA mutations (changes) from their parents that greatly increase their risk for developing certain cancers. But inherited gene mutations are not believed to cause very many cancers of the larynx or hypopharynx.
Gene changes related to these cancers usually happen during life, rather than being inherited. These acquired mutations often result from exposure to cancer-causing chemicals, like those found in tobacco smoke. Acquired changes in genes such as the TP53 and p16 tumor suppressor genes seem to be important in laryngeal and hypopharyngeal cancers, although not all cancers have these changes. Several different gene changes are probably needed for cancer to develop, and not all of these changes are understood at this time.
Inherited mutations of oncogenes or tumor suppressor genes rarely cause these cancers, but some people seem to inherit a reduced ability to detoxify (break down) certain types of cancer-causing chemicals. These people are more sensitive to the cancer-causing effects of tobacco smoke, alcohol, and certain industrial chemicals. Researchers are developing tests that may help identify such people, but these tests are not yet reliable enough for routine use.
Some forms of human papilloma virus (HPV) are emerging as important causes of some throat cancers (including cancers of the hypopharynx). Patients who develop HPV-linked throat cancers are less likely to have used tobacco and alcohol heavily. The outlook for people with these cancers appears to be better than for people whose cancers are the result of tobacco or alcohol use.
Last Medical Review: 12/14/2012
Last Revised: 01/18/2013