ABCC4 and familial pancreatic carcinoma: The fact that we established that high MRP4 levels: (a) are typical of high-grade pancreatic cancer cell lines, (b) co-express with mesenchymal markers, (c) cause differential expression of genes related with chemotaxis, migration and adhesion, and (d) are upregulated in CTC from PDAC patients, led us to propose that MRP4 is coupled to cancer development and plays a role in the maintenance of an aggressive phenotype.