KRT14 and breast cancer: Despite the fact that LOXL3 is specifically expressed by the myoepithelial cells of the mammary gland and the observation that PyMT PDO models show focal upregulation of LOXL3 in CK14 positive cells that are in contact with collagen, we do not find an association between LOXL3 expression and triple negative/basal (ERNEG/PRNEG/HER2NEG) breast cancers (Supplementary Table 2; p = 0.721).