EXPRESSION OF BETA(2)-MICROGLOBULIN BY HUMAN BENIGN AND MALIGNANT MESENCHYMAL AND NEUROGENIC TUMORS

Human myosarcomas, liposarcomas, meningosarcomas, glioblastomas and ma lignant schwannomas, their benign counterparts and normal cells from w hich these tumours derive, were examined for the expression of beta2-M icroglobulin (beta2m). Formalin fixed specimens from these tumours wer e studied by light microscopy employing the immunoperoxidase method wi th the use of antibodies directed towards beta2m. The malignant tumour s showed a broad spectrum from unstained to strongly stained tumours, most pronounced among myosarcomas. In addition, most stained tumours d isplayed a mosaic staining pattern in that unstained areas alternated with stained. There was a tendency towards increased staining for beta 2m in malignant compared to normal cells; this was also observed in th e benign tumours although to a lesser degree. The results differ from most earlier studies, mainly of carcinomas which have shown a tendency towards down-regulation of MHC I molecules on the tumour cells. The r esults are discussed in relation to concepts of immune surveillance of tumours.