Milea Timbergen

45 distinguish the true treatment effects from natural growth behaviour. Moreover, the design of randomized controlled trials might be restricted by the rarity of the disease and the small number of DTF patients with an indication for systemic treatment. Despite these challenges, future studies should include signalling pathways other than Wnt/β-catenin signalling to uncover additional driver genes and pathways in DTF and to clarify the potential working mechanisms of target drugs in the setting of DTF. Acknowledgements We would like to thank Sabrina Gunput, MSc, from the Medical Library, Erasmus MC - University Medical Centre Rotterdam for assistance with the literature search. 2