In order to induce EMT, TNFα needs to be constantly present in vicinity to the tumor cells. Determination of the reversibility of the TNFα-induced EMT effects. (a) MCF-7 cells were stimulated by TNFα (1000 U/ml) for 72 hr, followed by determination of membranous expression of E-cadherin in live cells, using flow cytometry. (b) The non-stimulated cells of part (A) were grown for additional 72 hr without TNFα. In contrast, the previously-stimulated cells (by TNFα) were grown for additional 72 hr without (b1) or with (b2) TNFα (1000 U/ml). Thereafter, the membranous expression of E-cadherin was determined in live cells by flow cytometry. The experiment is a representative of n = 3.