Since different cancer cell types display differences in the expression and relevance of EMT regulators [30–32], current attention is focused on systematically analyzing EMT-TFs’ regulatory mechanism and EMT-TFs/miR-34a feedback loop, like the role of TWIST1, SLUG, ZEB1/2 and SNAIL1 in promoting BC migration, invasion and metastasis. This evidence concerns the gene TWIST1 and breast cancer.