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 .The MUM-1 protein (multiple myeloma 1) is a lymphocyte-specific transcriptional activator also known as interferon regulatory factor 4 expressed in the final differentiation stage of intra-germinal centre B cells. MUM-1 is a marker for post-germinal centre B cells, plasma cells, and subset of T cells and related lymphoma types in addition to Hodgkin cells. It is expressed in Plasma cell neoplasms, diffuse large B-cell lymphoma ABC type. It is also expressed in Hodgkin’s lymphoma, CLL, marginal zone lymphoma, DLBCL, malignant melanoma.