The complex pathways of Wnt 5a in cancer progression.

In contrast to the transforming members of the Wnt family, shown to be upregulated in many cancers, the role of Wnt 5a is still controversial. While it has been attributed a tumour suppressor function in some malignancies, there is increasing evidence of promigratory and proinvasive effects in others, mediated predominantly through the planar cell polarity pathway and activation of protein kinase C. Obviously, the outcome of an individual Wnt 5a signal is dependent on a multitude of variables, ranging from availability of receptors, downstream effectors, and inhibitors to external influences coming from the tumour microenvironment and the extracellular matrix.