Extramedullary hematopoiesis in cancer

Hematopoiesis can occur outside of the bone marrow during inflammatory stress to increase the production of primarily myeloid cells at extramedullary sites; this process is known as extramedullary hematopoiesis (EMH). As observed in a broad range of hematologic and nonhematologic diseases, EMH is now recognized for its important contributions to solid tumor pathology and prognosis. To initiate EMH, hematopoietic stem cells (HSCs) are mobilized from the bone marrow into the circulation and to extramedullary sites such as the spleen and liver. At these sites, HSCs primarily produce a pathological subset of myeloid cells that contributes to tumor pathology. The EMH HSC niche, which is distinct from the bone marrow HSC niche, is beginning to be characterized. The important cytokines that likely contribute to initiating and maintaining the EMH niche are KIT ligands, CXCL12, G-CSF, IL-1 family members, LIF, TNF alpha, and CXCR2. Further study of the role of EMH may offer valuable insights into emergency hematopoiesis and therapeutic approaches against cancer. Exciting future directions for the study of EMH include identifying common and distinct EMH mechanisms in cancer, infectious diseases, and chronic autoimmune diseases to control these conditions. Changes to hematopoiesis, or the creation of blood and immune cells, in cancers are the focus of this review by Barisas et al. They discuss conditions that promote extramedullary hematopoiesis (EMH), which produces blood cells outside the bone marrow. They also discuss the impact of tumor-derived factors, including interleukin-1 alpha and leukemia inhibitory factor, on EMH. The team recently discovered that these specific factors stimulate the development of myeloid cells known for suppressing the immune system and aiding tumor growth. This suggests that targeting the pathways associated with these elements could be a new approach to cancer treatment. Research also indicates that EMH might be a common characteristic in other inflammation-related diseases, providing unique opportunities for further studies.This summary was initially drafted using artificial intelligence, then revised and fact-checked by the author.