The patient is then injected with a drug that is non-toxic and harmless to healthy cells, but which becomes toxic on encountering the enzyme in the cancer cells, thereby causing those cells to die.
自殺基因療法就是利用病毒這種特性，把自殺基因放進癌細胞中，癌細胞便會產生這種蛋白質酵素，再給病人施打無毒藥劑，藥劑進入癌細胞被轉換成具有毒性，進而殺死癌細胞。