Used to treat certain blood cancers by mobilizing hematopoietic stem cells from the bone marrow into the bloodstream. This allows for easier collection of stem cells for autologous transplantation in patients with lymphoma or multiple myeloma. It works by blocking the CXCR4 receptor, disrupting the interaction between stem cells and the bone marrow stroma. Typically administered with granulocyte-colony stimulating factor (G-CSF) to enhance stem cell release. Also investigated for use in stem cell mobilization for gene therapy and in patients who failed prior mobilization attempts.