A number of molecular as well as histological abnormalities occur in the various subtypes of rhabdomyosarcoma (RMS):
N-Myc is over-expressed in embryonal RMS and C-Myc in alveolar rhabdomyosarcoma.
- Embryonal RMS does not have recurrent structural chromosome rearrangements, but has frequent chromosome gains (most notable gains in ERMS are chromosomes 2, 8, 11, 12, 13, and 20).
- Has a loss of heterozygosity at the 11p15 locus; with duplication of paternal genetic material and loss of maternal genetic material.
- The N-Ras and K-Ras genes are mutated in 35% of embryonal RMS
- 70% of alveolar RMS cases contain one of two recurrent chromosomal translocations: t(2;13)(q35;q14) or less commonly t(1;13)(p36;q14). These translocations do not occur in embryonal RMS.
- In disseminated disease, the translocation t(2;13)(q35;q14) is associated with a poorer prognosis.
General RMS at the Atlas of Genetics and Cytogenetics in Oncology and Haematology