title: Performance of a Commercially Available MAL Antibody in the Diagnosis of Primary Mediastinal Large B-Cell Lymphoma.
abstract: Myelin and lymphocyte (MAL) protein has been previously reported as a highly specific marker for distinguishing primary mediastinal large B-cell lymphoma (PMBL) from diffuse large B-cell lymphoma, not otherwise specified (DLBCL, NOS). However, there has not been a commercially available MAL antibody for immunohistochemistry. We identified a commercially available MAL monoclonal antibody and evaluated it by immunohistochemistry on 43 cases of PMBL and 63 cases of DLBCL, NOS. We also compared this with a CD200 antibody that was previously reported useful in distinguishing PMBL and DLBCL, NOS. A threshold of 10% positive tumor cells was used to determine positive protein expression. MAL was expressed in 72% cases of PMBL and 0% of cases of DLBCL, NOS (sensitivity=72%, specificity=100%). CD200 was expressed in 81% of PMBL cases and 13% of DLBCL, NOS cases (sensitivity=81%, specificity=87%). To our knowledge, this is the first report on the utility of a commercially available MAL monoclonal antibody in the diagnosis of PMBL. There is a high specificity with good sensitivity in distinguishing PMBL from DLBCL, NOS, similar to previous studies with a noncommercial source. This antibody will likely prove useful in identifying cases of PMBL in routine practice.
authors.affiliation: Department of Laboratory Medicine, Robert J. Tomsich Institute of Pathology and Laboratory Medicine, Cleveland Clinic, Cleveland, OH.
authors.forename: Michael
authors.initials: M
authors.lastname: Gentry
authors.forename: Juraj
authors.initials: J
authors.lastname: Bodo
authors.forename: Lisa
authors.initials: L
authors.lastname: Durkin
authors.forename: Eric D
authors.initials: ED
authors.lastname: Hsi
mesh_terms: D000328:Adult; D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D014408:Biomarkers, Tumor / Q000032:analysis*; D015153:Blotting, Western; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D016393:Lymphoma, B-Cell / Q000175:diagnosis*; D016403:Lymphoma, Large B-Cell, Diffuse / Q000175:diagnosis; D008297:Male; D008479:Mediastinal Neoplasms / Q000175:diagnosis*; D008875:Middle Aged; D062806:Myelin and Lymphocyte-Associated Proteolipid Proteins / Q000032:analysis*; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; D062806:Myelin and Lymphocyte-Associated Proteolipid Proteins