CASC2 inhibits miR-18a-5p level, and downregulating miR-18a-5p inhibits MM cell proliferation, migration, and invasion. (A) The miR-18a-5p level in MM tissues and normal skin tissues using qRT-PCR. (B) The miR-18a-5p level in A375 cells with pc-CASC2 or pcDNA3.1 (blank) using qRT-PCR. (C) The binding site between CASC2 and miR-18a-5p. (D) The luciferase reporter assay in cells with CASC2-wild type (wt) or CASC2-mutant (mut). (E) The miR-18a-5p level in A375 cells with miR-18a-5p inhibitor or inhibitor control using qRT-PCR. (F) The colony number of A375 cells with miR-18a-5p inhibitor and inhibitor control using the colony formation assay. (G) The migratory cell number of A375 cells with miR-18a-5p inhibitor or inhibitor control using Transwell analysis. (H) The invasive cell number of A375 cells with miR-18a-5p inhibitor or inhibitor control using Transwell analysis. *p < 0.05 and ***p < 0.001 compared with normal, blank, or inhibitor control.