Cancer Genes Coding for Growth Factors or Receptors for Growth Factors: Her-2 or neu or erbB-2 is a gene that codes for a growth factor receptor that sits on the cell's surface and relays a growth-stimulating signal to the cell's interior, the nucleus. The mutant gene has been detected in breast, salivary gland, and ovarian cancers.

The Sis oncogene product is a mutant or an altered form of a growth factor called platelet-derived growth factor. It is known to be associated with gliomas, a type of brain cancer.

RET proto-oncogenes code for a growth factor receptor. The mutant protein product of RET is associated with thyroid cancer.

Cancer Genes in the Cytoplasm Involved in Relaying Growth Signals: Ras proto-oncogenes code for proteins in the cytoplasm that drive the growth of the cell. Mutations in ras have been detected in lung, ovarian, colon, and pancreatic cancers.

APC (adenomatous polyposis coli) tumor suppressor gene codes for a cytoplasmic protein that relays extracellular signals from cell adhesion protein on the outside of the cell to the nucleus. The mutated protein is found in almost all colon tumors and a large percentage of benign colon polyps.

NF-1 is a tumor suppressor gene that codes for a protein located in the cytoplasm that functions in signal transduction. Alterations in the gene's protein product are involved in cancers (neurofibromas) of the peripheral nervous system.

Cancer Genes that Function Normally as Transcription Factors: The Myc protein is a transcription factor produced by the myc proto-oncogene. Transcription is the biochemical process that takes place in the nucleus of the cell by which a gene's DNA is "read" or transcribed into a specific message (RNA), which is in turn converted into a specific protein. The mutated Myc protein alters which proteins are produced in a cell and is associated with uncontrolled growth of cells.

The protein product of the p53 tumor suppressor gene normally functions as a transcription factor in the cell. Normal p53 protein prevents cells with damaged DNA from growing. If damage is major, p53 protein will accumulate in the cell, triggering cell death (apoptosis). The altered p53 protein is associated with many different cancers.

Other Genes Associated with Cancer: MSH-2 and MLH-1 are two genes known to function normally in DNA repair. Their mutated forms are associated with a form of colon cancer, hereditary nonpolyposis colon cancer. Alterations in these genes are also found in other tumors.

NTS-1/p16 is a tumor suppressor gene that normally functions as a cell cycle inhibitor. When mutated, the gene's protein product is associated with malignant melanoma and pancreatic cancer.

Cancer Genes Associated with Specific Cancers: Mutations in BRCA1 and BRCA2 proto-oncogenes increase an individual's risk for developing breast and ovarian cancers. Both normal proteins appear to be involved in transcriptional regulation and DNA repair.

Mutations in Rb1 are associated with childhood tumors of the eye and other tumors. The RB protein normally regulates transcription.

Mutations in APC gene are associated with colorectal cancer.

Mutations in MSH-2 and MLH-1 are associated with a form of colorectal cancer, hereditary nonpolyposis colon cancer.

Mutations in VHL are associated with von Hippel-Lindau syndrome, a condition that includes benign and malignant tumors of the kidney, retina, central nervous system, pancreas, and adrenal gland. The normal protein product is involved in transcriptional regulation.

Mutations in the NF1 gene are found in nerve tumors. The normal protein product activates other proteins.

Mutations in the RET gene are associated with thyroid and adrenal cancers. The normal protein product activates is a growth factor receptor.

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