Predictive Value of micro-RNA Expression Profiling in Pediatric Desmoid Fibromatosis

Background: Lack of clinical predictors of desmoid fibromatosis (DF) outcome highlight the need for biological markers to anticipate DF behavior. In this study we assessed micro-RNA expression profiles in a cohort of children with DF and correlated these findings with patient outcomes aiming to detect predictors of DF outcome.Procedure: A retrospective analysis of 40 DF patients treated at the Children Cancer Hospital Egypt from January 2007 to December 2016 was carried out. Based on initial treatment approach, patients were categorized into three groups. Upfront excision was performed in 14 patients (35%). Nine patients (23%) were subjected only for careful observation while 17 patients (43%) received upfront metronomic chemotherapy. Tumor samples underwent micro-RNA expression analysis. Both unsupervised analysis as well as predictive supervised analysis was performed for the entire cohort.Results: Median time to progression was 71.7, 26.9 and 8.7 months for observation group, chemotherapy and upfront surgery respectively with P = 0.002. Among the nine untreated patients (observation group), four (44%) of them progressed which was strongly correlated with downregulation of miR-378a-5p & hsa-miR-133a-3p, Padj < 0.05. Extremity site was the location for 23 patients, 15 (65%) of them experienced progression. Three downregulated miRNAs hsa-miR-378a-3p, hsa-miR-1-3p and hsa-miR-451a were differentially expressed for those with disease progression, Padj < 0.05.