Immunohistochemical staining for apolipoprotein B in human sarcomas

A study of immunocytochemical staining for apolipoprotein B (apo B) in 52 human sarcomas and eight benign soft-tissue tumors is described. A peroxidase-antiperoxidase technique was employed using a rabbit anti-apo B antiserum. All 27 liposarcomas examined were positive for apo B, and 23 of these tumors showed at least 2-plus staining on a scale of 0 to 3 plus. Of the ten myxoid liposarcomas within this group, seven showed 2-plus or 3-plus staining, while the other three stained 1 plus. By contrast, 11 of 13 malignant fibrous histiocytomas were negative for apo B; the remainder showed 1-plus staining. Myxoid areas present in three of these cases were negative for apo B. Five of seven rhabdomyosarcomas stained at least 2 plus for apo B. Both benign and malignant peripheral nerve sheath tumors showed no consistent pattern of staining. We conclude that apo B immunocytochemical staining tends to be high in tumors whose normal tissue counterparts exhibit relatively large numbers of low-density lipoprotein receptors. Furthermore, immunoperoxidase staining for apo B should be a useful adjunct in the evaluation of soft-tissue sarcomas, particularly in cases with myxoid differentiation.