LRP6 and cancer: We also demonstrated that the high cancer selectivity of NT4 peptides is due to their multimericity, which allows binding to membrane sulfated glycosaminoglycans (GAG) as well as to different membrane endocytic receptors of the low density lipoprotein receptor (LDLR) family, like LRP1 and LRP6, which are already known as potentially druggable tumor markers involved in many aspects of cancer biology.