IL9 and hepatitis B virus infection: Serum IL-9 level was notably reduced in both CHB patients (103.8 ± 12.95 pg/mL), and hepatitis B-related HCC patients (95.27 ± 12.53 pg/mL) compared with in NC (134.6 ± 6.49 pg/mL) (P<0.0001, SNK-q tests, Figure 2A).