S-100 proteins (S100s) is a heterogeneous fraction of dimeric polypeptides (alpha and beta subunits) that can exist in different combination forms within the various tissues.

Members

Immunochemistry in normal cells

 dendritic cells

• interdigitating reticulum cells
• Langerhans cells
• follicular dendritic reticulum cells

), other S-100-positive cells belonging to the mononuclear/phagocytic system

Immunochemistry in tumor cells

 follicular center cell lymphoma