Uncovering Rare RUNX1-USP42 Gene Fusions in Pediatric AML

BACKGROUND

Pediatric acute myeloid leukemia (AML) accounts for about 25% of childhood cancer cases. While survival rates have risen dramatically in the past few decades, 30% of patients still relapse. Fortunately, recent studies have uncovered a variety of genetic abnormalities specific to the disease that both (A) provide important hints about its clinical course and (B) may serve as therapeutic vulnerabilities.

THE STUDY

A recent publication - Pediatric acute myeloid leukemia with t(7;21)(p22;q22) - dug deeper into one of these abnormalities, the RUNX1/USP42 gene fusion, in a small cohort of pediatric AML patients. In all 3 cases, conventional karyotyping revealed a reciprocal translocation between chromosomes 7 and 21. This ruled out the possibility of many of the more frequent RUNX1 fusions, and lead the team to test for RUNX1/USP42 using fluorescent in situ hybridization (FISH.) Beyond RUNX1/USP42, the patients were also found to harbor additional abnormalities, the most common being 5q and 11p deletions.

TAKEAWAY

This team expanded on an incredibly rare AML-specific gene fusion, one that could’ve been easily ignored if it wasn’t for careful genetic testing. Then, drawing on the 12 cases already reported, they managed to narrow in on several unique genetic and clinical features shared by these patients. Findings like these are invaluable in cancer detection, monitoring, and profiling, especially for subtypes, like pediatric AML, with a high rate of relapse.