CD79α is encoded by the mb-1 gene and was previously called Igα. The antibody recognizes an extracellular epitope expressed on the CD79α molecule. Results aid in the classification of B-cell neoplasms in routine biopsy material. In addition to the expression in B cells, CD79α has been found to be co-expressed with CD3 in 10% of cases of T-lymphoblastic leukemia/lymphoma. Antibodies to CD79α may also be a useful aid for classification of Hodgkin's disease.