TWIST1 and neoplasm: In the TME, CSCs could transdifferentiate into cells (such as TECs) that differ from their own original lineage along the axis of Twist1-Notch-KLF4 [7] or differentiate into their original lineage of tumor cell progeny, of which the latter differentiation process is bidirectional, meaning that the differentiated tumor cells can conversely dedifferentiate into CSCs.