IImmunology--Study of the body's mechanisms of resistance against disease or invasion by foreign substances.
Immunotherapy--A treatment that stimulates the body's own defense mechanisms to combat disease, such as cancer.
In Situ--In place; localized and confined to one area. A very early stage of cancer.
Incidence--The extent to which disease occurs in the population. Cancer incidence is the estimated number of new cases of cancer diagnosed each year.
Interferon--A natural body protein produced by normal cells that is capable of killing cancer cells or stopping their unrestrained growth. Interferon was originally discovered as an antiviral agent, but has now been found to have some anti-cancer activity as well. Interferon may be artificially produced in large quantities using the technique of recombinant DNA.
Involuntary Smoking--When nonsmokers breathe cigarette smoke from other people, they are involuntarily smoking. The risk of lung cancer in nonsmokers is now being studied. Also called passive smoking, side-stream smoking and second-hand smoking.