CCL22 and osteosarcoma: Additionally, Wolf-Dennen et al. revealed that exosomes released by metastatic osteosarcoma cells initiate a conversion in alveolar macrophages towards a tumor-promoting M2 phenotype by activating IL10, TGFB2, and CCL22 mRNA, a process correlated with diminished capability in eradicating apoptotic cells and tackling tumor cells, thereby contributing to increased immune suppression and tumor progression in osteosarcoma (Wolf-Dennen et al., 2020).