Breastfeeding could drive terminal differentiation of breast ductal cells via increased production of the GATA family of transcription factors, specifically GATA-3, which has been shown to actively maintain the differentiated luminal epithelium actively; thus, conferring protection from aberrant transcription changes, GATA-3 may play a causal role in the loss of tumor differentiation and malignant conversion in breast cancer. Here, GATA3 is linked to breast cancer.