Human CXCL1 (C-X-C motif chemokine ligand 1), also known as GRO-α (growth-regulated oncogene alpha), is a proinflammatory chemokine belonging to the CXC chemokine family, which includes related chemokines such as CXCL2 (GRO-β), CXCL3 (GRO-γ), and CXCL8 (IL-8) that regulate neutrophil recruitment during inflammatory responses. In humans (Homo sapiens), CXCL1 is produced by macrophages, epithelial cells, endothelial cells, fibroblasts, and tumor cells in response to infection, inflammatory cytokines, or tissue injury. CXCL1 primarily signals through the chemokine receptor CXCR2, promoting chemotaxis, activation, and migration of neutrophils and other innate immune cells to sites of infection or inflammation. Through these actions, CXCL1 plays an important role in host defense against bacterial infections and regulation of acute inflammatory responses, particularly in tissues such as the lung, skin, and gastrointestinal tract. Dysregulated CXCL1 expression has also been implicated in chronic inflammatory diseases, cancer progression, and tumor-associated inflammation, where CXCL1-mediated neutrophil recruitment and angiogenic signaling can influence the tumor microenvironment and disease progression. Because of its role in neutrophil trafficking and inflammatory signaling, human CXCL1 is widely studied in immunology, cancer biology, and inflammatory disease research.