Triple-negative breast cancer, pregnancy, and HLA alloreactivity: a cause for concern?

Triple-negative breast cancer (TNBC) remains the most aggressive form of breast cancer in women worldwide, with an incidence that varies considerably depending on genetic background and ethnicity. Since parity is a known risk for TNBC, here we propose that in HLA alloreactivity resulting from immunization against paternal antigens expressed by the fetus, 50% fetus-mother HLA dissimilarity in natural pregnancy and 100% fetus-mother HLA dissimilarity in surrogate motherhood, may be a risk factor in women with predisposing genetic background and ethnicity due to immune suppression and immunologic tolerance vis-à-vis a developing breast cancer with TNBC characteristics.