TP53 and hepatocellular carcinoma: For example, exposure to ultraviolet light is correlated with TP53 transitions at dipyrimidine sites (CC>TT) [12]; aflatoxin B1 exposure with G∶C>T∶A transversions in codon 249 in hepatocellular carcinoma; and exposure to cigarette smoke with G∶C>T∶A transversions in lung carcinoma [12].