APC and intestinal neoplasm: Quantitative RT-PCR analysis of the isolated tumors showed that expression of the WNT target genes and stem cell markers Lgr5, Ascl2, and Axin2 were suppressed in the Usp7 cKO tumors (Figure 3D), suggesting that Usp7 depletion inhibits WNT signaling in the Apc-deficient intestinal tumors.