ESR1 and breast cancer: GATA3 codes for a transcription factor that is particularly abundant in luminal epithelial cells and directly correlates with ESR1 expression, thus is considered a marker of luminal breast cancer11,12, whereas S100B belongs to a family of genes coding for calcium-binding inflammatory proteins, regulators of p53, and might be involved in acid-induced EMT of ER-positive breast cancer cells in vitro14.