CHEK2 and mantle cell lymphoma: However, the pathogenesis of MCL is complex and the alterations in the genes involved in DNA damage response (ataxia telangiectasia mutated [ATM], checkpoint kinase 2 [CHK2], and TP53) and cell survival signalling pathways (Bruton’s tyrosine kinase [BTK], mammalian target of rapamycin [mTOR], nuclear factor-κB [NF-κB], tumour necrosis factor [TNF], and NOTCH) also play crucial roles5.