TGFB1 and cancer: To gain abundant high-purity CSCs by sphere culture based on the expression of a limiting ratio of differentiated cancer cells and CSCs in (5), we suggest the following regulatory measures: obtaining a highest initial ratio of CSCs, inhibiting the differentiation or asymmetric division of CSCs and promoting the conversion of differentiated cancer cells to CSCs, such as by culturing with TGF-β to boost EMT [15], [26].