Identification and Characterization of the Gene Responsible 
for Neurofibromatosis Type 1 
stitute for GAPs in switching oflf growth signals 
that might otherwise resuh in uncontrolled pro- 
liferation of cells and produce a tumor. 
Thus the NFl product may have a role in hu- 
man biology that is much broader than its rele- 
vance-to neurofibromatosis, as important as that 
will prove to be for NFl sufferers and their fami- 
lies. The NFl protein is likely to open new ave- 
nues of inquiry about normal cellular processes 
and about events that lead to cancer. Projects to 
investigate several of these avenues are now 
under way in our laboratory. 
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