Five-Gene Panel Confirmed as Diagnostic for High-Risk Pediatric Rhabdomyosarcoma

By LabMedica International staff writers
Posted on 28 Oct 2015

A recently published paper confirmed the usefulness of a five-gene panel for identifying children with a high risk form of the muscle cancer rhabdomyosarcoma (RMS).

RMS has two common histological subtypes: embryonal (ERMS) and alveolar (ARMS). PAX–FOXO1 fusion gene status has been shown to be a more reliable prognostic marker than alveolar histology, whereas fusion gene–negative (FN) ARMS patients are clinically similar to ERMS patients. Children with FN-RMS usually present with a more aggressive form of the disease.

Image: Photomicrograph of alveolar rhabdomyosarcoma showing nodules of tumor cells separated by hyalinized fibrous septae (50x, HE stain). Inset: Discohesive large tumor cells with hyperchromatic nucleus and scant cytoplasm (200x, HE stain) (Photo courtesy of Wikimedia Commons).

A five-gene expression signature (MG5) was shown previously to identify two diverse risk groups within the population of FN-RMS patients, but this had not been independently validated.

In the current study, investigators at The Institute of Cancer Research (London, United Kingdom) used a NanoString Technologies (Seattle, WA, USA) nCounter analysis system to profile MG5 gene expression in samples taken from 68 patients from the Children's Oncology Group's (Monrovia, CA, USA) D9803 study of children with intermediate-risk RMS.

Results revealed that the MG5 signature score showed a significant correlation with overall and failure-free survival. The MG5 test sorted fusion-negative patients into two distinct groups, based on the activity of the five genes. Patients with high scores had significantly worse survival chances than those with low scores, suggesting the test could ultimately be included in assessment of children with RMS.

"Our research showed a significant link between a particular gene signature from tumor samples and higher-risk, aggressive rhabdomyosarcoma. This study is an important step towards introducing an approach that identifies children who are unlikely to benefit from current, standard treatments and can be offered more intensive or new treatment strategies that will improve their outcome," said contributing author Dr. Janet Shipley, professor of cancer molecular pathology at The Institute of Cancer Research. "We now hope to bring our test for this gene signature to the clinic as soon as possible. Our aim is to identify these high-risk cases of rhabdomyosarcoma more quickly in the clinic, and ultimately improve treatment for these children."

The paper was published in the October 15, 2015, online edition of the journal Clinical Cancer Research.

Related Links:
The Institute of Cancer Research
NanoString Technologies
Children's Oncology Group