Melanoma

S-100is structurally similar to calmodulin and gets its name from the fact that it is 100% soluble in ammonium sulfate at neutral pH.

Also known as MART-1, for Melanocytic Antigen Recognized by cytotoxic T lymphocytes from melanoma patients, it is a sensitive and specific cytoplasmic protein for melanoma.

The brain tissue surrounding this metastatic tumor mass has acute neuronal necrosis.