Oncogenes up-regulate cell division. If they are mutated or translocated to another site, cells may divide out of control, causing cancer. A contributing factor can be mutations in tumor suppressor genes, which dampen the ability of cells to divide. If tumor suppressor genes mutate or are translocated, the body's normal controls against cancerous growth can be lost. With 10 million cells dividing in the human body every minute, and the external environment impacting upon the body, genetic mutations inevitably occur.
Humans also have genes which can repair DNA damage.
But if these repair genes themselves become mutated, DNA errors may go uncorrected. An early accomplishment by Jefferson's cancer researchers was the identification of a gene that plays a crucial role in promoting types of leukemia and lymphoma. Cancer occurs when the TLC-1 gene is moved out of its normal sequence on chromosome 14, and placed next to other elements known as enhancers which cause the gene to produce too much of its protein product. Recently, Jefferson investigators led by Dr. Croce and Professor Kay Huebner, Ph.D. discovered the FHIT gene, the second largest gene yet identified, which is involved in many common cancers. All Rights Reserved.