The specific monoclonal antibody, DF3, for breast cancer and the correspond
ing tumor marker CA15-3 were evaluated in 108 patients with primary cancer
of the breast. These antigens correlated poorly with the known prognostic p
arameters. Elevated CA153 serum values were associated with the cytoplasmic
distribution of the DF3 antigen in the cell. The DF3 distribution pattern
and the CA15-3 serum values had prognostic significance for disease-free in
terval.