USP7 and breast carcinoma: Circ0100519 can be encapsulated in exosomes and transported to tumor-associated macrophages by serving as a molecular scaffold to enhance the interaction between the deubiquitinating enzyme USP7 and nuclear factor NRF2 [143], which results in NRF2 deubiquitination modification mediated by USP7, in turn stimulating M2-type macrophage polarization and eventually accelerating breast cancer invasion and metastasis.