RSPO3 and prostate carcinoma: Similar to our in vitro experiments, 22RV1.shRSPO3 cells displayed higher rates of extravasation in CAM assay compared to 22RV1.shCtrl cells (Fig. 3d; 5.7 ± 1.0% versus 15.0 ± 1.9% extravasation; a 2.6-fold increase), further supporting a tumour-suppressor role for RSPO3 in prostate cancer.