S100A11, also known as S100C and Calgizzarin, is a calcium binding protein that is secreted by keratinocytes and can be crosslinked by transglutamination in the cornified envelope of the skin. It binds to RAGE to induce keratinocyte proliferation and the production of EGF family proteins as well as chondrocyte hypertrophy and catabolism of the cartilage matrix. S100A11 is upregulated in various cancers where it supports tumor cell proliferation, invasion, and migration. In addition, S100A11 is produced in the ovary, and it acts on cumulus cells to inhibit oocyte fertilization. Calcium promotes S100A11 association with S100B as well as Annexins A1, A2, and A6.