S100 calcium binding protein A8 (S100-A8) is also kown as Cystic fibrosis antigen, Migration inhibitory factor-related protein 8 60B8AG, CAGA, CFAG, CGLA, CP-10, L1Ag, MA387, MIF, MRP8, NIF and P8, is a member of the S100 family of proteins containing 2 EF-hand calcium-binding motifs. S100 proteins are localized in the cytoplasm and/or nucleus of a wide range of cells, and involved in the regulation of a number of cellular processes such as cell cycle progression and differentiation. S100 genes include at least 13 members which are located as a cluster on chromosome 1q21. Most S100 proteins are disulfide-linked homodimer, and is normally present in cells derived from the neural crest, chondrocytes, macrophages, dendritic cells, etc. S100A8 plays a role in various functions of myeloid cells by forming a heterocomplex with S100A9. S100A8 and S100A9 are known to be overexpressed in certain species of carcinomas. S100A8 may function in the inhibition of casein kinase and as a cytokine. Altered expression of this protein is associated with the disease cystic fibrosis. S100A8 plays an important role in differentiation of thyroid carcinoma possibly by forming a complex with S100A9. S100A8 and S100A9 may also play a key role in inflammation-associated cancer.