[Mechanism of tumorigenesis caused by tumor suppressor gene]

Hereditary cancer syndrome is mainly caused by tumor suppressor genes, such as p53 gene in Li-Fraumeni syndrome and p16 gene in familial melanoma. There are 2 signal pathways of regulation of cell cycle, RB pathway and p53 pathway. Cyclin dependent kinase(CDK) was regulated by CDK inhibitor(CDKI) (p16, p15), and CDK-CDKI complex control RB by phosphorylation. p53 regulate RB pathway through p21. p53 is involved in apoptosis through bcl 2 or Bax 3. p19 coded by exon 1 beta and exons 2 and 3 of p16 gene, binds to MDM2 and regulate p53 pathway. Chromosome 9p21 locus, which p16, p15 and p19 genes are assigned, is important to regulate both RB and p53 pathways.