In addition, they described that HIF-1α plays a critical role in collagen biogenesis in breast tumors by upregulating the expression of P4HA1, P4HA2, PLOD1, and PLOD2 hydroxylases as well as the lysyl oxidase family members LOX, LOXL2, and LOXL4. This evidence concerns the gene P4HA1 and breast neoplasm.