Through the comparison of miRNA profiling of ovarian cancer-derived exosomes in normoxia with those in hypoxia using miRNA microarray, they showed that several miRNAs, such as miR-21-3p, miR-125 b-5p and miR-181 d-5p, were enriched in hypoxic ovarian cancer-derived exosomes They further demonstrated that these three miRNAs regulate the SOCS4/5/STAT3 pathway to modulate macrophage M2 polarization [29]. Here, STAT3 is linked to ovarian cancer.