PPARG and osteosarcoma: Interestingly, PPARγ also acts as an E3 ligase, mediating ubiquitination at Lys28 and leading to p65 proteasomal degradation, directly linking lipid metabolism to immune modulation in the tumor microenvironment (219).Targeting the UPS-PPARγ axis holds potential for modulating FA metabolism and inflammation, particularly in pediatric cancers like osteosarcoma and NB (209–214, 220).