VHL and breast cancer: Importantly,compound CSI212, synthesized as a negativecontrol having the 4-hydroxy group of 4-hydroxyproline in the S conformation (versus the VHL-based degraders with the4-hydroxy group in R conformation), did not haveany antiproliferative effect in prostate and breast cancer cell lines,further implicating the importance of the E3 ligase recruitment forpotency in cell lines.