Consistent with these findings, immunohistochemical (IHC) analyses of human breast cancer biopsy samples revealed that ΔNp63α and FOXO3a protein levels were significantly decreased in invasive breast cancer specimens compared to primary breast cancer specimens, whereas ATF6 and GRP78 protein levels were markedly increased in invasive breast cancer specimens (Fig. 6B, C). Here, ATF6 is linked to breast cancer.