A method for treating cancer by inducing a double strand DNA break at a chromosomal site in cancer cells, inserting a nucleic acid encoding a suicide gene into the chromosomal site having the double strand DNA break, and expressing the suicide gene in the cancer cells, thereby inducing cell death upon expression of the suicide gene. The chromosomal site includes a protospacer adjacent motif (PAM) absent from a corresponding chromosomal site in normal cells. Also disclosed is a cancer treatment method that includes identifying a single nucleotide change in the genomic sequence of cancer cells from a subject as compared to the genomic sequence of normal cells, the single nucleotide change forming a PAM, inserting a suicide gene specifically into the cancer cell genomic sequence, and activating the suicide gene, thereby leading to cell death. Furthermore, provided is a clustered regularly interspaced short palindromic repeat-associated protein having RNA-guided DNA endonuclease activity.
