Squamous cells of the skin make up the middle and outer layers of the skin.
Normally, cells in the body will grow and divide to replace old or damaged cells. This growth is usually precise. Once enough cells are produced to replace the old ones, normal cells stop dividing. Tumors occur when there is an error and cells continue to grow uncontrollably. Squamous cell skin cancer develops from squamous cells.
Squamous cell carcinoma most often appears on areas of the body that have been exposed to the sun, but may occur anywhere on your body. Squamous cell carcinoma is usually not life-threatening, but left untreated, squamous cell skin cancer can spread to other parts of the body (metastasize).