Are Long Noncoding RNAs New Potential Biomarkers in Gastrointestinal Stromal Tumors (GISTs)? The Role of H19 and MALAT1

Long noncoding RNAs (lncRNAs) are emerging as key regulators of genetic and epigenetic networks, and their deregulation may underlie complex diseases, such as carcinogenesis. Several studies described lncRNA alterations in patients with solid tumors. In particular, HOTAIR upregulation has been associated with tumor aggressiveness, metastasis, and poor survival in gastrointestinal stromal tumor (GIST) patients. We analyzed expression levels of other lncRNAs, H19 and MALAT1, in FFPE tissue specimens from 40 surgically resected and metastatic GIST patients, using real-time PCR analysis. H19 and MALAT1 were both upregulated in 50% of GIST patients. MALAT1 lncRNA expression levels seem to be correlated with c-KIT mutation status. The percentage of both H19 and MALAT1 upregulation was significantly higher in patients with time to progression (TTP) < 6 months as compared to patients with TTP > 6 months. The median TTP was significantly lower in patients with both H19 and MALAT1 lncRNA upregulation as compared to those with lncRNA downregulation. These data suggest a potential role for both H19 and MALAT1 lncRNAs as prognostic biomarker for the clinical selection of the best candidate to first-line treatment with imatinib.