Fig. 1.

Role of AFB₁ in development of HCC. AFB₁ is activated by metabolism to form an electrophilic epoxide, which binds to DNA to form mutagenic AFB₁-DNA adducts. The two adducts shown, AFB₁-N⁷-Gua and AFB₁-FAPY, are mutagenic in vivo and cause the type of mutation that is seen most frequently in HCCs (the G:C→T:A transversion). Shortly after dosing, it is proposed that a “founder” or “exposure” mutational spectrum forms. As the tissue ages, subsequent mutational processes continue to mature the founder spectrum into the mutational spectrum seen in end-stage cancer.