Aflatoxin
Aflatoxin is a toxin produced by aspergillus fungi that can contaminate food when exposed to certain environments, mostly warm and humid ones. Exposure can cause hepatocellular carcinoma without cirrhosis. Aflatoxin is mostly present in developing countries.
Aflatoxin causes a very characteristic mutation in the p53 gene called a signature mutation. If this mutation is present in an HCC it’s certain that the etiology was aflatoxin.