Bioinformatics tools and dual-luciferase reporter assays indicated that miR-340-3p was a potential target gene of H19 that acted as a ceRNA to promote BC cell proliferation, metastasis, and EMT by regulating tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta (YWHAZ) and potentiating the Wnt/β-catenin signaling in BC cells. The gene discussed is YWHAZ; the disease is breast cancer.