[Protein S-100 in the histological diagnosis of tumors]

Review deals with the use of the antibodies against protein S-100 in the diagnosis of tumours in man and experimental animals. Protein S-100 was first isolated from the bovine brain and then identified in glial and Schwann cells of the nervous system, epidermal Langerhans cells, myoepithelial cells of the salivary and mammary glands and in many other cells of various organs. In spite of the lack of specificity to any tissue antibodies against protein S-100 are widely used in the diagnosis of human tumours, mainly for the differentiation between neurogenic and soft tissue tumours (positive response to S-100 protein is regularly observed in benign schwannomas, neurofibromas and granular cell tumours while fibroblastic tumours are S100-negative), for the differentiation between nonpigmented melanomas (positive) and anaplastic carcinomas (negative). The knowledge of S-100 protein distribution in normal organ facilitates the establishment of the tumour origin. Antibodies against S-100 protein allowed one to establish the neurogenic origin of some rat soft tissue tumours which were considered otherwise to be of mesenchymal origin and gave additional proof of the neurogenic origin of the rat endocardial tumours.