CXCR4 and posterior cortical atrophy: Here we show that activation of CXCL12-CXCR4 axis upregulates the expression of TWIST2. Hence, we may speculate that overexpression of S18-2 leads to induction of CXCR4 expression and, consequently, TWIST2 upregulation and repression of epithelial markers in PCa cells.