Are CTCs metastatic precursors?

Yu et al. (1) recently described the use of microfluidic technology to capture circulating tumor cells (CTCs) labeled with green fluorescent protein (GFP) from a mouse pancreatic cancer model. Single-molecule RNA sequencing demonstrated that WNT2 is selectively highly expressed in the CTCs. Expression of WNT2 in human pancreatic cancer cells was found to suppress anoikis (apoptosis induced by cell detachment), enhance anchorageindependent sphere formation, and increase metastatic potential.