The invention relates to the use of compounds of general structure (I) in modulation of the Wnt pathway wherein R1, R2, R3, R4 and R5 are each, independently, H or an alkyl group; D is selected from the group consisting of H, halogen, alkyl, cycloalkyl, aryl, and dialkylamino, each (other than H and halogen) being optionally substituted; Ar is an aryl or heteroaryl group, optionally substituted; Cy is an aryl, heteroaryl or a saturated ring containing at least one heteroatom, each being optionally substituted; and n is an integer from 1 to 3.