Overview Mechanism loss of function mutation in a tumor suppressor gene regulate cell growth and repair damage see Cell cycle topic because one functioning tumor suppressor gene copy can produce enough functioning protein to prevent neoplasia, two allele alterations needed for neoplasia two-hit model note many of the inherited cancer disorders have an inherited loss of 1 copy Examples Tumor Suppressor Genes Gene Associated Tumor Chromosome APC Colorectal cancer (associated with FAP) 5 p16 Melanoma 9 WT1 Wilms' tumor 11 Rb Retinoblastoma and osteosarcoma 13 BRCA2 Breast cancer 13 NF1 Neurofibromatosis type 1 17 BRCA1 Breast and ovarian cancer 17 TP53 Most human cancers and Li-Fraumeni syndrome 17 DPC Pancreatic cancer (stands for deleted in pancreatic cancer) 18 DCC Colon cancer (stands for deleted in colon cancer) 18 NF2 Neurofibromatosis type 2 22