According to the Human Protein Atlas high or medium expression of HDAC1, HDAC2, HDAC9, HDAC10, SIRT3, SIRT5, SIRT6, SIRT7 is present in 100% of patients with breast cancer (Figure 6A); while in carcinoid tumors is HDAC1, HDAC4, HDAC9, SIRT7 (Figure 6B). This evidence concerns the gene HDAC9 and breast cancer.