A murine monoclonal antibody to human breast cancer cells associated with DNA ploidy status.

A murine monoclonal antibody, 5D10, raised against the human breast cancer cell line MCF7 reacted preferably with mammary carcinomas and weakly with normal epithelial cells. The antigens recognised by the antibody had molecular weights of about 28 and 90 kD. The reactivity of the antibody to human breast carcinomas correlated with the DNA ploidy status of the tumour cells. Upon analysis of 54 breast carcinoma specimens, the percentage of antibody positive cells was significantly higher in tumours with an aneuploid stemline than in those with a diploid DNA content (P less than 0.001). This antibody therefore could be a useful tool in evaluating the prognosis of breast carcinomas.