miRNA Expression in PDGFRA Mutant GISTs. miRNA Expression in PDGFRA Mutant GISTs

Context: Gastrointestinal stromal tumors (GISTs) harboring mutations in the PDGFRA gene occur in only about 5–7% of patients. The most common PDGFRA mutation is exon 18 D842V, which is corre-lated with specific clinico-pathological features compared to the other PDGFRA mutated GISTs. Herein, we present a miRNA expression profile comparison of PDGFRA D842V mutant GISTs and PDGFRA with mutations other than D842V (non-D842V). miRNA expression profiling was carried out on 10 patients using a TLDA miRNA array. Then, miRNA expression was followed by bioinformatic analysis aimed at evaluating differential expression, pathway enrichment, and miRNA-mRNA networks. We highlighted 24 differentially expressed miRNAs between D842V and non-D842V GIST patients. Pathway enrichment analysis showed that deregulated miRNAs targeted genes that are mainly involved in the immune response pathways. The miRNA-mRNA networks highlighted a signature of miRNAs/mRNA that could explain the indolent behavior of the D842V mutated GIST. The results highlighted a different miRNA fingerprint in PDGFRA D842V GISTs compared to non-D842Vmutated patients, which could explain the different bio-logical behavior of this GIST subset. Overall design: qPCR miRNA expression profiling. Total RNA from serum of 10 GIST patients was extracted and PDGFRA Exon 18 D842V GISTs versus PDGFRA Exon 18 non D842V GISTs