It is well-established that solid tumors in which the Wnt/β-catenin pathway is activated are immunologically cold and thereby insensitive to immune checkpoint inhibition. Several mechanisms have been reported to underlie this association but much remains to be experimentally validated. Using TALEN or CRISPR/Cas9 mediated disruption of the tumor suppressor gene APC in Xenopus tropicalis we previously generated a genetic model for Gardner syndrome, characterized by the presence of desmoid tumors, a tumor type strictly driven by Wnt pathway activation in absence of additional oncogenic insults. We meanwhile identified EZH2, which encodes a member of the polycomb repressive complex 2, as a dependency factor for these tumors. Furthermore, treatment of Xenopus carrying established desmoid tumors with the EZH2 inhibitor Tazemetostat caused a significant reduction in desmoid tumor volume. We found that the drug reduces Wnt/β-catenin pathway activity in human desmoid cell cultures without exhibiting an overt effect on cell proliferation or cell death. Therefore, we postulate that Tazemetostat induced tumor regression observed in the Xenopus model occurs via alleviating an immune suppressive environment and allowing the engagement of a natural anti-tumor immune response. Using a range of genetic experiments in Xenopus tropicalis this working hypothesis will be investigated.