hsa-mir-619: Hsa-mir-619 is a key miRNA that is positively correlated with the presence of STC, while the other six key miRNAs show a negative correlation [PMC7646872]. Hsa-mir-619 is part of the turquoise module, along with hsa-miR-20b, hsa-miR-128, hsa-miR-129-3p, hsa-miR-30b, and hsa-miR-340 [PMC7646872]. In addition to its positive correlation with STC, hsa-mir-619 also shows negative correlations with other miRNAs such as hsa-miR-20b and hsa-miR-486-3p [PMC7646872]. Hsa-mir-619 and hsa-mir9 are both downregulated in both subtypes of STC and target the tumour suppressor gene MDGA2 [PMC5951834]. HSA-MIR495 (CDH2), HSA-MIR382 (FGA), HSA-MIR20A (MMP2, MMP3, CTSK), HSA-MIR449A (P2RY14), HSA-MIR5765P (F9), and HSA-MIR619 (KNG1) are predicted targets of various miRNAs [PMC6391078]. Interestingly, both hsa-mir619 and hsa-mir548a2 are derived from different types of transposable elements (TEs) [PMC7345915]. The hairpin structure of pre-miRNAs, such as hsa-mir-326, hsa-mir-421, and hsa-mir-619, is formed by TEs inserted in proximity to appropriate sequences that are similar to complementary sequences of TE heads or tails [PMC4482582]. The wild-type sequence contains binding sites for both miRNA binding sites for hsa-miR-4254 and hsa-mir-619, while the mutant sequence contains binding sites for hsa-miR-1207-3p and hsa-miR-3135b [PMC6377377].