SOX2 and neoplasm: SOX2 expression has previously been reported to be associated with increased expression of the Wnt effector genes AXIN2 and DKK1 (12), although in our analysis of TCGA tumor tissue samples, the expression levels of AXIN2 or DKK1 were not significantly correlated with those of SOX2. This lack of correlation suggests that the SOX2 and Wnt signaling pathways may be partially independent of each other; Wnt induction of AXIN2 and DKK1 may form negative feedback loops that dampen Wnt signaling, reducing the functional linkage to Wnt pathway inhibitor sensitivity (17, 31).