Tumour cells import FFAs from the extracellular space and adipocyte. Subsequently, these can be stored into LDs to prevent the accumulation of ROS or degraded through β-oxidation to promote tumour growth and metastasis. LD accumulation is also triggered from ER stress to alleviate stress. In dendritic cells (DCs), accumulation of LDs dysregulates antigen presentation of tumour-associated antigens which may inhibit immune response. In parallel, LD-localised prostaglandin E2 (PGE2) might be secreted causing immunosuppression. In tumour cells, PGE2 promotes cell proliferation and cell survival. COX-2, cyclooxygenase-2.