Differences in the microRNA expression of G1 and G2 pancreatic neuroendocrine tumors (A19)

Introduction: Targeted testing of microRNAs implicated in the biology of pancreatic neuroendocrine tumors (PNET) was performed via RT-QPCR to uncover differentially expressed microRNAs that could be used as diagnostic markers characteristic for tumor grade.

Aim(s): By extending the sample cohorts included in our last year’s study, we have reexamined the expression of hsa-miR-96-5p and hsa-miR-130b-3p, and also tested two further microRNAs (hsa-miR-106b and hsa-miR-194-5p).

Materials and methods: Now, in total, 33 formalin-fixed paraffin-embedded (FFPE) tissue samples were included (16 grade 1 and 17 grade 2). The samples were sectioned for RNA isolation and sections were evaluated by expert pathologists to have the specific grade and region of interest containing the tumor tissue only. Total RNA was isolated with Recover ALL Kit (Thermo Fisher Scientific) from 80 µm of FFPE sections and the expression levels of hsa-miR-96-5p, hsa-miR-106b, hsa-miR-130b-3p, and hsa-miR-194-5p were determined and analyzed compared to the geometric mean of RNU48 internal control and cel-miR-39 external spike-in-control as calibrators by quantitative RT-qPCR on Quant studio 7 Flex instrument using TaqMan chemistry.

Results: Both hsa-miR-130b-3p (p=0.0110) and hsa-miR-194-5p (p=0.0245) were significantly underexpressed in G2 PNET as compared to G1, whereas hsa-miR-96-5p and hsa-miR-106b were not significantly different.

Conclusion: In conclusion, hsa-miR-130b-3p and hsa-miR-194-5p could be promising biomarkers to differentiate G1 and G2 PNET, and their circulating counterparts might also be investigated in liquid biopsy samples.

Keywords: mirna expression, pnet g1 and g2, rt-qpcr, hsa-mir-130b-3p, hsa-mir-194-5p, hsa-mir-96-5p, hsa-mir-106b, ffpe tissue