The leukocyte migration inhibition response to certain breast cancer-related antigens (MCF-7 and MuMTV): their potential as discriminants.

Certain oncogenic viruses have been implicated in human breast cancer, including the murine mammary tumor virus (MuMTV) and the Mason-Pfizer monkey virus (MPMV). We have used the leukocyte migration inhibition (LMI) response to assay the response to several potential breast cancer-related antigens, including MuMTV, MPMV, and a breast cancer cultured cell line, MCF-7, in 96 breast cancer patients, in 32 women with benign breast disease, and in 67 normal women. The lowest tenth percentile of control (LMI) responses was used as the cutoff point to designate responders. Breast cancer patients showed significant responses to MuMTV (49% and to MCF-7 (50%), but not to MPMV (29%). In a paired-antigen study using MuMTV and MCF-7, 75% of the breast cancer patients responded, versus 18% of the normal women (P less than 0.0050). The potential for this assay to distinguish "normal" from "breast cancer" was analyzed using a migration index derived from discriminant analysis. The ability of the assay to discriminate "normal" from "cancer" was significant (P less than 0.001) and showed a sensitivity of detecting "cancer" of 75%. The overall responses to MuMTV and MCF-7 were analyzed with reference to certain prognostic factors, but showed no relation to age, menstrual status, estrogen receptor status, or stage of disease. The above reactions suggest that a large proportion of breast cancer patients exhibit presensitization to antigenfs found in MuMTV and MCF-7, which may be cross-reactive with antigens in the primary cancer. These responses appear to be independent of major prognostic variables. Further refinement of this assay may yield one which is more highly discriminating for breast cancer.