miR-21, one of the most commonly upregulated miRNAs in solid cancers [68], is induced by TGF-β [69,70] and has been found to induce EMT in different cancer cell lines [70,71,72], with activation of Akt and ERK1/2 signalling seeming to be critical in the promotion of EMT by miR-21 [71,73]. The gene discussed is TGFB1; the disease is cancer.