The significant increase of miR-140-5P in papillary thyroid cancer samples

Abstract Background and objective Epi-miRNAs as a class of miRNA target genes involved in the epigenetic pathway like DNMTs and HDACs. They can play a role as a proto-oncogene or tumor suppressor. The present study evaluates the expression pattern of miR-140-5P, as a commonly mentioned tumor suppressor that targets DNMT1 and HDAC4 genes, in papillary thyroid cancer (PTC). Methods 32 tissue and normal tumor margins samples of PTC were collected. The relative expression of miR-140-5P, DNMT1, and HDAC4 genes were evaluated and compared between these two groups. Results The results revealed no significant change in the relative expression of DNMT1 and HDAC4 in PTC samples. However, the expression of miR-140-5P, contrary to our hypothesis, significantly increased in the tumor group compared to the control. Conclusion According to the common role of miR-140-5P as a tumor suppressor gene in different groups of cancer, the expression increasing of it seems not to be acceptable. However, considering the increased expression of miR-140-5P as only reason for declining this role is also not sufficient.