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 .CD34 is a cell surface adhesion glycoprotein expressed on the surface of precursor hematopoietic cells of myeloid and lymphoid lineage, a subset of mesenchymal stem cells and endothelial cells, and a large number of tumours originated from these cells. CD34 is a widely used marker to highlight blood vessels and vascular tumours, but it is less specific than CD31.