CXCR4 and neoplasm: Circ-TMX4 acts as a sponge for miR-622, resulting in upregulation of CXCR4, a key mediator of metastasis, thus establishing the ERβ1/circ-TMX4/miR-622/CXCR4 axis as a novel pathway linking ERβ1 to tumor aggressiveness and therapy response [111].