On the other hand, HIFs downregulate several proteins such as tissue factor pathway inhibitor (TFPI) through binding to negative HREs sequences, which were identified as 5′-GACATG-3′ [13] and 5′-AAACAGGA-3′ in the human breast cancer MCF-7 cell line [14]. The gene discussed is TFPI; the disease is breast carcinoma.