The major source of VEGFC during pregnancy has been postulated to be the uterine natural killer (uNK) cells, but some positive staining for VEGFC in the extravillous trophoblast has also been observed [40] . We saw significant induction of VEGFC by PSG1 in HTR-8/SVneo cells, which express high basal levels of this growth factor, but this was not reproducible in four other independent experiments (Fig. 6D ).