+ -Text Size  Causes, Risk Factors, and Prevention TOPICS  Do we
know what causes rhabdomyosarcoma?  Researchers still do not
know what causes most cases of rhabdomyosarcoma (RMS), but they
are learning how certain changes in DNA can cause normal cells
to become cancerous. DNA is the chemical in each of our cells
that makes up our genes – the instructions for how our cells
function. It is packaged in chromosomes (long strands of DNA in
each cell). We normally have 23 pairs of chromosomes in each
cell (one set of chromosomes comes from each parent). We usually
look like our parents because they are the source of our DNA.
But DNA affects more than how we look.   For example, people
with Li-Fraumeni syndrome have changes in the TP53 tumor
suppressor gene that cause it to make a defective p53 protein.
The p53 protein normally causes cells with DNA damage to either
pause and repair that damage or, if repair is not possible, to
self-destruct. When p53 is not working, cells with DNA damage
continue to divide, causin