Use of HBA 71 and anti-beta 2-microglobulin to distinguish peripheral neuroepithelioma from neuroblastoma.

Peripheral neuroepithelioma (PN) can be difficult to distinguish from undifferentiated neuroblastoma (NBL) in the absence of molecular and cytogenetic studies. These primitive neural tumors of childhood are similar in morphology and immunocytochemistry, despite their distinct biochemical and behavioral characteristics. The recently developed monoclonal antibody HBA 71 is specific for the product MIC2, a marker of peripheral primitive neuroectodermal tumors. Because beta 2-microglobulin also is selectively expressed by most tumors in this subset, we examined whether a combination of the antibodies HBA 71 and anti-beta 2-microglobulin could facilitate the differentiation of the two malignancies. We histologically confirmed the diagnoses of 45 paraffin-embedded tumors of presumed neuroectodermal origin (19 PNs and 26 NBLs) from the pathology files of St Jude Children's Research Hospital. Samples were immunohistochemically stained using HBA 71 and anti-beta 2-microglobulin. Molecular and cytogenetic data were correlated with the results in a subset of eight patients. Sixteen (84%) of the 19 PNs reacted with HBA 71 and 13 (76%) of 17 PNs reacted with anti-beta 2-microglobulin. None of the NBLs reacted with either antibody. Three PNs were identified by HBA 71 alone and one was identified by anti-beta 2-microglobulin alone. Cellular genetic findings were consistent with the results. HBA 71 and anti-beta 2-microglobulin, when used in combination, can facilitate the differential diagnosis of PN and NBL.