title: False-positive rate of the immunoperoxidase stains for MART1/MelanA in lymph nodes.
abstract: MART1 and MelanA are considered sensitive markers of melanocytic differentiation and are used to increase the detection of melanoma micrometastases in sentinel lymph nodes (SLNs). However, the false-positive rates of these two antibodies have not been adequately evaluated. We examined 217 lymph nodes (LNs) from patients with no history of melanoma: 117 SLNs from breast cancer patients, 79 LNs from other nonmelanoma malignancy patients, and 21 reactive LNs. Capsular melanocytic nevi were identified in 5 SLNs from 5 breast cancer patients by both antibodies. Two of these 5 SLNs with capsular nevus also contain MART1- and MelanA-positive cells within the lymph node parenchyma. Individual immunoperoxidase-positive cells were also identified within the parenchyma of lymph nodes without capsular nevus (9 LNs with MART1 and 3 LNs with MelanA). The false-positive rate is 5.1% for MART1 and 2.4% for MelanA. In conclusion, MART1- or MelanA-positive cells may be present in lymph nodes from patients without melanoma. Therefore, MART1- and MelanA-positive cells in SLNs from melanoma patients, without corresponding atypia or hematoxylin and eosin findings, should be interpreted with caution.
authors.affiliation: Department of Pathology, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756, USA.
authors.forename: Shaofeng
authors.initials: S
authors.lastname: Yan
authors.forename: Jeoffry B
authors.initials: JB
authors.lastname: Brennick
mesh_terms: D000951:Antigens, Neoplasm; D015415:Biomarkers / Q000032:analysis; D001943:Breast Neoplasms / Q000737:chemistry / Q000473:pathology; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008198:Lymph Nodes / Q000737:chemistry* / Q000473:pathology; D058965:MART-1 Antigen; D009363:Neoplasm Proteins / Q000032:analysis*
chemical_list: D000951:Antigens, Neoplasm; D015415:Biomarkers; D058965:MART-1 Antigen; C548667:MLANA protein, human; D009363:Neoplasm Proteins