S100A2 belongs to the S100 family of proteins containing 2 EF-hand calcium-binding motifs. S100A2 may function as a modulator against excess calcium accumulation in normal human mammary epithelial cells and also have a role in suppressing tumor cell growth. This protein may have a tumor suppressor function. Chromosomal rearrangements and altered expression of this gene have been implicated in breast cancer. Cytoplasmic overexpression may also be of prognostic significance when observed in oral cancer patients, and the S100A2 has also been identified as significantly down-regulated in gastric cancer.