• Study of molecular features of Her2‐low and BC• Three groups Her2+, Her2−, Her2‐low• PA: taurine/hypotaurine metabolism increased in HR− v HR+ Her2‐low BC• PA: NS: glutathione, cysteine/methionine, ascorbate/aldarate metabolism in HR− vs. HR+ Her2‐low. This evidence concerns the gene ERBB2 and breast cancer.