CHEK2 and neoplasm: Certain carcinogenic bacteria, such as pks+ Escherichia coli (E. coli) and ETBF, encode and secrete carcinogenic toxins that induce DNA damage, which results in faster tumour onset and greater mortality.140 Moreover, FadA, a key adhesin secreted by F. nucleatum, promotes E-cadherin/β-catenin activation to upregulate checkpoint kinase 2 (CHK2), causing DNA damage in mouse CRC cells.141F.