There are many types of head and neck cancer. They typically begin in the squamous cells of the mouth, nose, and throat, according to the National Cancer Institute (NCI). Squamous cells are flat cells on the surface of the skin or that line hollow organs or tubes, such as the windpipe. But what causes these cancers? One of the most important risk factors is infection with the human papillomavirus (HPV). Read on to learn more about this connection.