The PMR value for the Mex3a promoter was remarkably lower in patients with HBV-associated HCC (median: 0.289% and interquartile range: 0.126%–0.590%) than in those with CHB (median: 0.999%, interquartile range: 0.417%–1.268%, and p < 0.001) and significantly lower than in HCs (median: 2.172%, interquartile range: 1.225%–3.098%, and p < 0.001), as determined by the Kruskal–Wallis test. This evidence concerns the gene MEX3A and hepatocellular carcinoma.