Wessex Branch of the Association of Clinical Pathologists, December 1990 Meeting

j Y a'med to assess the reliability of a panel of antibodies in ' perent'a' diagnosis of lymphomas and germ cell tumours, n n'f ant'b?dies commonly used in lymphoma panels ^ CA, L26, MBl, MB2, CD21, UCHL-1, CD3, and CD30), the germ cell tumour marker, placental alkaline phosphatase and EMA were applied to paraffin sections of 16 seminomas, 15 teratomas and one mixed tumour. Reactivity was demonstrated using a streptavidin-biotin peroxidase method. The sections were screened by two investigators for reactivity with the tumour elements, lymphocytic infiltrate and normal testicular tissues. Antibodies MB1, MB2 and BerH2 reacted with seminomas. Occassional staining of undifferentiated teratoma cells with CD3 was observed. Tumour cells were negative with LCA, L26, CD21 and UCHL-1. MB2 (and occasionally MB1 and UCHL-1) stained mature germ cells and Leydig cells. In conclusion staining with MB1, MB2 or UCHL1 should not be regarded as diagnostic of lymphoma. LCA, L26, CD21 and CD5 should be included in any panel used in the diagnosis of mediastial tumours.