In a major research advance, scientists at the University of Texas Southwestern
Medical Center in Dallas have identified the cells that cause tumors to form
in neurofibromatosis type 1 when a "good gene" goes bad. Their work may ultimately
shed light on the way in which many common cancers begin.
Luis Parada, a molecular biologist, and colleagues at UT Southwestern and in
France, developed genetically engineered mice that had one good and one bad
copy of the NF1 gene - the gene linked to the disease. They were able to show
that Schwann cells, which insulate nerve fibers, are the cells that start a
tumor when the good copy of the gene mutates.
The neurofibromatoses are genetic disorders that cause many benign tumors,
which may eventually become malignant, to grow along various types of nerves.
The disease also can affect the bones and skin, and sometimes includes developmental
abnormalities such as learning disabilities. It's been classified into two types:
NF1 and NF2. In NF2, in addition to basic neurofibromatosis symptoms, people
experience hearing loss.
In addition to the initial finding, the research showed that mast cells, which
are immune system cells, assist in the formation of tumors. Tumors formed only
when the mast cells also had one bad copy of the NF1 gene. This finding is important
because it sheds light on the role of non-cancerous cells in forming tumors.
That may ultimately help to explain why, for instance, some people known to
inherit cancer-causing mutations don't develop the disease.