Copy number gain of the 1q32.1 chromosomal region was shown in cases of HB and HCC, including in 28 of 56 HB tumors in a study that showed that this was the most frequent allelic imbalance in HB tumors, and MDM4 has been proposed as the candidate oncogene in this amplicon19–21. This evidence concerns the gene MDM4 and hepatocellular carcinoma.