Squamous Cell Carcinoma

Squamous cell are relatively hearty cells since they are exposed to the environment during breathing; however, they can only tolerate cigarette smoke and other toxic substances for a certain period of time. Squamous cell carcinoma shows a remarkable dose-dependence with cigarette smoking. This means that the risk of developing this types of lung cancer increases in direct proportion to the number of cigarettes smoked over time.

Squamous cell carcinoma is the second most common type of lung cancer accounting for about 30% of all lung cancers. Squamous cells are “scale-shaped” and occur along the “tubes” of the lungs, that is, the trachea and bronchi. Under a microscope, squamous cell carcinoma is characterized by “keratin pearls” that are recognized by a pathologist. In some ways squamous cells are like skin cells: they can tolerate contact with air (for the most part) and they tend to slough off (exfoliate) like skin cells.

In contrast to lung adenocarcinoma, squamous cell carcinoma is usually found near the center of the lungs. While it is usually not possible to obtain a biopsy of squamous cell carcinoma from the outside of the body, it may be possible to collect cells for analysis from the inside. To perform a biopsy in this fashion, a bronchoscope (a thin tube with a light, a camera, and small surgical instruments in the tip) can be advanced down the throat, into the trachea, and to the bronchus that contains the tumor.