Squamous cell carcinoma of the lung is the growth of abnormal cells in the lung. These abnormal cells increase in number and produce a tumor. Squamous cell carcinoma is one of the non-small cell lung cancers. Most squamous cell tumors tend to start in the center of lungs and often spread to other parts of the body. Current or previous smokers, people with asbestos or radon exposure are at greater risk for development of this type of cancer.