Significantly lower miRNA-34a-5p and miRNA-200c-3p expression levels were observed in the HS578T-Hyg breast cancer cells, M13HS-2 and -8 tumor hybrids and their ZEB1-KO variants, in comparison to the M13SV1-EGFP-Neo breast epithelial cells. The gene discussed is ZEB1; the disease is breast cancer.