CCND1 and mantle cell lymphoma: Of note, KPT-185 strikingly targeted cyclin D1 and its downstream signaling in MCL cells, and the blastoid-variant Z138 with high baseline expression of cyclin D1 was the most sensitive to KTP-185 among the tested MCL cell lines, suggesting that cyclin D1 is a critical target of KPT-185 for its anti-tumor activity.