Scientists have designed a biocomputer which can identify and kill cancer cells without harming the healthy ones. Biocomputers use biologically derived materials such as DNA or proteins to perform programmed functions.
http://www.ummid.com/news/2011/September/05.09.2011/biocomputer_kills_cancer_cells.htm
http://www.ummid.com/news/2011/September/05.09.2011/biocomputer_kills_cancer_cells.htm