The most common include the following: (i) luminal A and luminal B, characterized by low (luminal A) or high (luminal B) levels of the protein Ki-67, while both expressing estrogen receptor (ER) and progesterone receptor (PR), but not the human epidermal growth factor receptor (Her2); (ii) Her2 positive, expressing Her2, but not ER or PR; and (iii) triple-negative breast cancer (TNBC), expressing none of the above-mentioned receptors. This evidence concerns the gene PGR and triple-negative breast carcinoma.