Test Details: Immunohistochemical testing is carried out on biopsy/resected tissue specimen. This testing helps to identify specific antigens (proteins) within tissue sections utilizing an antigen-specific antibody .S100 protein family consists of about 25 homologous low molecular weight intracellular calcium-binding proteins encoded by different genes located at different chromosomes, mainly chromosome 1. It is expressed in Melanomas, schwannoma, histiocytic (Langerhans cell) neoplasms and neuroendocrine tumours.