CHEK1 and Hodgkins lymphoma: By using cluster analysis on immunohistochemical results, considering the whole panel of DDR activation markers, aggressive B-cell neoplasms (DLBCL and BL) clearly clustered together, being characterized by higher constitutive CHK1, CDC25c, and H2AX phosphorylation, whereas indolent B-cell neoplasms and HL formed a separate cluster (Figure 1A).