Polyketide-peptide genotoxin-induced DNA double stranded breaks, incomplete DNA repair, and induced aneuploidy and tetraploidy [50] Colibactin dependent mutations likely through alkylation of DNA on adenine residues and subsequent double stranded DNA breaks [51] Infection by cancer-associated E coli. Increased COX-2 expression by macrophages in a p38 MAPK dependent manner [52]. Here, PTGS2 is linked to cancer.