DETECTION AND ENRICHMENT OF CARCINOMA-IN-SITU CELLS IN SEMEN BY AN IMMUNOMAGNETIC METHOD USING MONOCLONAL-ANTIBODY M2A

Carcinoma-in-situ (CIS) is a precursor of germ cell cancers in the tes tis. Early detection and treatment of CIS can prevent the development of invasive cancer. We have developed an immunomagnetic approach for e nrichment of CIS cells from semen. Immunomagnetic beads were coated wi th monoclonal antibody (mAb) M2A, which is specific for seminoma and C IS. In preliminary mixing experiments, cultured human HEY cells, which express the M2A surface antigen, were added to semen samples and reco vered selectively by incubation with M2A-coated immunomagnetic beads f ollowed by magnetic activated cell sorting (MACS). Application of this procedure to ejaculates from five subjects with CIS and 22 control su bjects with no evidence of testicular neoplasia resulted in the prefer ential recovery of a population of large round cells from a 0.5 ml sem en sample obtained from CIS subjects (median 1 x 10(4), range 2 x 10(3 ) to 2 x 10(4)) relative to controls (median 2 x 10(2); range 0 to 10( 3)), with no overlap between the two groups (p<0.001). These results s uggest that a subpopulation of large round cells recovered from the se men of CIS patients by incubation with M2A-coated immunomagnetic beads and MACS are CIS cells. Immunomagnetic enrichment of CIS cells in sem en will facilitate the definitive identification of exfoliated CIS cel ls in ejaculates and could be an important first step in a non-invasiv e screening procedure for testicular CIS.