When LOXL2 was knocked down in two independent breast cancer cell lines, Eo771 and MDA-MB-231 expressing high endogenous LOXL2 levels16, 59, XBP1 splicing and transactivation of the UPRE and ERSE gene reporters were abrogated or strongly decreased in both cell lines (Fig. 3a,b). Here, LOXL2 is linked to breast carcinoma.