부산대학교 도서관

Cell growth and division is a complex process that is controlled by various factors. Both positive control (when factors turn a process on) and negative control (when factors turn a process off) exist. The protein p53 is a negative regulator, known as a tumor suppressor gene. The normal gene encoding the protein inhibits growth of cancer cells grown in tissue culture and inhibits growth of tumors in animals. The p53 protein and its effect can be altered or inactivated by genetic mutations (changes) or through interactions with DNA tumor viruses. This alteration or inactivation can lead to the development of cancer or uncontrolled cell growth. The p53 gene can also be altered in a way that it then can actually stimulate cell division. These types of genetic changes appear to occur very commonly in human cancer. An altered p53 gene has been found in cancers that are inherited, such as Li-Fraumeni syndrome, (a syndrome characterized by multiple cancers at different sites in the body), but also in cancers that are not inherited. A mutated p53 gene has been found in 75 to 80 percent of colon cancers that have been analyzed. Other types of cancer in which mutated p53 genes are found include lung cancer, brain and breast tumors, and chronic myelogenous leukemia. (Consumer Summary produced by Reliance Medical Information, Inc.)