ABSTRACT
Retinoic acid, through its signaling and downstream transcriptional targets, regulates the development and activity of hematopoietic cells and their myeloid and lymphocytic progenitors. The hematopoietic sites and the circulatory system (including both blood and lymph) have important multifaceted roles in the relationship between inammation and cancer. Their components are responsible for the homeostasis in the entire organism. They are involved in many processes, including delivering nutrients and removing waste; removing the preneoplastic/neoplastic cells or infectious agents like viruses, which could promote cancer, or in contrast, promoting angiogenesis and sustained inammation, which promotes solid tumor growth and metastasis; or becoming malignant themselves, as in the case of leukemias and lymphomas. Retinoic acid (RA), a metabolite of vitamin A, is an important regulator of differentiation, development, and functions of the hematopoietic and immune systems. This chapter tries to highlight some of the signaling events elicited by RA in the blood and immune cells.
