(American Association for Cancer Research) – Among children with intermediate-risk rhabdomyosarcoma (RMS) that is negative for a fusion gene, those who had a high score of a specific gene signature called MG5 had poorer survival outcomes compared with those who had a low score of MG5, according to a study published in Clinical Cancer Research, a journal of the American Association for Cancer Research.
The study was conducted using archived tumor samples from patients enrolled in the Children’s Oncology Group D9803 clinical trial, and the results suggest that a risk-stratification approach using the MG5 score has the potential to be readily adaptable across all clinics if validated in a bigger cohort.
“RMS is a rare but aggressive malignancy of childhood and is of two types, embryonal and alveolar, based on histology. Most alveolar RMS are positive for PAX-FOXO1 gene fusions, which portends an unfavorable prognosis,” said Pooja Hingorani, MD, clinical assistant professor of pediatrics at the University of Arizona College of Medicine in Phoenix, and an attending physician of the Solid Tumor Team at Phoenix Children’s Hospital.
Hingorani explained that for patients with fusion gene-negative RMS, no molecular prognostic factors are currently employed in the clinic to identify those that may have poorer outcomes; hence, all receive similar treatment based on the clinical-pathological features of their tumors.
“We tested whether the expression of a five-gene signature, MG5, in these fusion gene-negative, intermediate-risk patients may be able to divide them into two separate risk groups. MG5 was previously identified and shown in a separate cohort to be associated with outcome. If increased risk of relapse or progression could be identified upfront, treatment might be intensified. Conversely, for patients who are identified as having a decreased risk of relapse or progression, we might be able to decrease their therapy and minimize toxicity,” Hingorani said.