Using the TIMER and QUANTISEQ algorithm, we found a positive correlation between the expression of FANCD2 in Hepatitis B-related HCC and the infiltration levels of B cells (P, 8.18e−07; P Spearman, 0.4), CD4 + T cells (P, 5.15e−06; P Spearman, 0.37), CD8 + T cells (P, 0.54; P Spearman, 0.05), Neutrophil (P, 1.31e−07; P Spearman, 0.42), Macrophage (P, 1.95e−06; P Spearman, 0.38), Myeloid dendritic cells (P, 1.25e−08; P Spearman, 0.45), and Treg cells (P, 0.001; P Spearman, 0.28) in Fig. 6. The gene discussed is CD4; the disease is hepatitis B virus infection.