CHEK1 and mantle cell lymphoma: The JEKO-1 and JEKO-1 R cells were equally sensitive to bendamustine and bortezomib, two chemotherapeutic drugs commonly used in clinic for the treatment of MCL [25], and to other DNA damaging agents implying that the acquisition of the resistance to Chk1 inhibitors should not be related to resistance to other chemotherapeutic drugs.