Diverse mechanisms for activation of Wnt signalling in the ovarian tumour microenvironment

Wnt signalling pathways have been shown to play key roles in both normal development and tumorigenesis. Progression of many human cancers is associated with defined mutations in Wnt pathway components that result in dysregulated beta-catenin-mediated gene transcription. Although Writ pathway mutations are rare in epithelial ovarian cancer (with the exception of the endometrioid histotype), accumulating evidence supports a role for Writ signalling in ovarian tumorigenesis in the absence of genetic mutations. The present review summarizes evidence in support of activated Wnt signalling in ovarian tumours and discusses alternative mechanisms for Writ pathway activation in the ovarian tumour microenvironment.