Most of the cancers arise due to changes in the lifestyle, including tobacco, smoking, and alcohol abuse, bacteria and viruses. Cytokines are a group of small, mainly secreted proteins that affect the behaviour of cells in a diverse number of ways. The binding of cytokines to specific cell membrane cytokine receptors can induce a number of activities within the cell, such as growth, differentiation, or death. This text book emphasize the role of cytokines in carcinogenesis of smokers and chewers. In addition to diagnostic tools like vital staining, biopsy, chemiluminescence, tissue fluoresecence cytokines can also be used as a marker for cancer.