CXCR2 and posterior cortical atrophy: We next knocked down TCF7L1 and further treated cells with the WNT4 protein, and found that TCF7L1-KD cells exhibited abolished expressions of WNT4-mediated IL-8 and CXCR2 (Fig. 5G, H), supporting that WNT4 upregulation associated with IL8/CXCR2 expression is TCF7L1-dependent in PCa cells.