SE-derived ncRNAs regulate tumor metastasis. A. The transcription factor ZEB1 binds to the SE region upstream of lncRNA HCCL5 to activate its expression; activated SE-derived HCCL5 accelerates the EMT phenotype of hepatocellular carcinoma (HCC) by upregulating the expression of Snail, Slug, ZEB1, and Twist1. B. C19MC is overexpressed when transcription factor TTYH1 binds to the SE region and initiates the C19MC-LIN28A-MYCN circuit by inhibiting LIN28A and upregulating MYCN to regulate the progression of embryonal tumors with multilayered rosettes (ETMRs). C. The transcription factors FOS, ZEB1, and MAX bind to the SE region potentially upstream of the LINC00152 promoter; knocking out LINC00152 inhibits the invasion and metastasis of breast cancer cells. D. Transcription factor YY1 combines p65/p300 to form a transcription complex to promote quaking (QKI) expression by binding to the SE regions of QKI; meanwhile, QKI can cause the formation of circ-0008150 and circ-0007821 to promote the expression of EMT-related markers vimentin and zeb1 by adsorbing miR-615-5p and miR-381-3p.