This assay was based on the evaluation of 21 genes, of which 16 are tumor-associated and five used as controls; the 16 cancer-related genes include five genes that are involved in proliferation (Ki-67, STK15, Survivin, Cyclin B1, MYBL2), invasion (Stromelysin 3, Cathepsin L2), estrogen (ER, PR, Bcl2, SCUBE2), HER2 (GRB7 and HER2), and GSM1, BAG1, and CD68 [58]. This evidence concerns the gene ESR1 and cancer.