LOXL4 and breast cancer: HIFs promote premetastatic niche formation by regulating the expression of multiple members of the LOX family of proteins (LOX, LOXL2, LOXL4) and different family members were found to be expressed in different human breast cancer biopsies and induced by hypoxia in different breast cancer cell lines, but in all cases the induction was HIF-dependent and could be blocked by HIF inhibitors [27, 43].