POPDC1 and breast cancer: The hypothesis that cAMP-mediates inhibition of breast cancer cell migration and proliferation via POPDC1 signalling is further strengthened by restoration of the cell migration and proliferation in MCF7, MDA231 and SKBR3 cells by elevating cAMP following POPDC1 knockdown (Figure 7A and B) which suggests that these effects are dependent upon a cAMP-induced increase in POPDC1 levels.