CDKN1B and osteosarcoma: Although Antxr1 knockdown was reported to reduce Ccnd1 and to increase Cdkn1a and Cdkn1b expression in osteosarcoma cells [32], their expression was not changed in the limb cartilage of Antxr1 tg mice compared with that in wild-type mice at E15.5 by microarray analysis (data not shown).