In the diabetic non-HCC group, Actinobacteria exhibited a significant inverse relationship with HbA1c (r = −0.52, p = 0.008), and Spirochaetes demonstrated strong positive correlations with both AFP (r = 0.710, p = 0.048) and total bilirubin (r = 0.821, p = 0.012). This evidence concerns the gene AFP and hepatocellular carcinoma.