ZEB2 and head and neck squamous cell carcinoma: PTEN [26] and zinc finger E-box-binding homeobox 2 (ZEB2) [27], which are direct target genes of miR-21 and miR-221, respectively, are significantly downregulated in HNSCC cells treated with exosomes derived from FaDu spheroid + CAF co-culture compared to exosomes derived from FaDu cell + CAF co-culture or other single culture.