anti-CD79a Molecule, Immunoglobulin-Associated alpha (CD79A) (Extracellular Domain) antibody: CD79alpha is non-covalently associated with membrane-bound immunoglobulins on B-cells to constitute the B-cell Ag receptor. CD79alpha first appears at pre B-cell stage and persists until the plasma-cell stage, where it is found as an intracellular component. CD79alpha is found in the majority of Acute Leukemias of precursor B-cell type, in B-cell lines, B-cell Lymphomas, and in some Myelomas. CD79alpha is a B-cell marker that is generally used to complement CD20. This antibody will stain many of the same Lymphomas as CD20, but also stains more B-precursor Lymphoid Leukemias than CD20. CD79alpha also stains more cases of Plasma-cell Myeloma and occasionally some types of endothelial cells as well. CD79alpha will stain many cases of Acute Promyelocytic Leukemia (FAB-M3), but only rarely stains other types of Myeloid Leukemia. Immunohistochemistry (IHC) is a complex technique in which immunological and histological detection methods are combined. In general, the manipulation and processing of tissues before immunostaining, especially different types of tissue fixation and embedding, as well as the nature of the tissues themselves may cause inconsistent results (Nadji and Morales, 1983). Endogenous pseudoperoxidase and peroxidase activity or endogenous biotin and alkaline phosphatase activity can cause non-specific staining results depending on the detection system used. Tissues that contain Hepatitis B surface antigen (HBsAg) can produce false positives when using HRP detection systems (Omata et al, 1980). Insufficient contrast staining and/or improper mounting of the sample may influence the interpretation of results.