Mechanistically, circ0001666 acts as a sponge for miR-1251 to weaken the inhibition of miR-1251 on the downstream target SOX4, and the high expression of SOX4 in turn regulates the EMT of cancer cells by upregulating the expression of EZH2 and promoting the invasive properties of pancreatic cancer cells (94). The gene discussed is SOX4; the disease is cancer.