The results showed that the level of IL-2 and TNF-α in Th1 cells in the observation group was higher than that in the control group at 3 months after treatment (P < 0.05), whereas the levels of IL-4, IL-6, and IL-10 in Th2 cells were lower than those in the control group (P < 0.05) indicating that iodine-125 seed implantation combined with chemotherapy in patients with primary liver cancer can maintain the balance of Th1/Th2 cells in peripheral blood, enhance the body's immunity, and facilitate the recovery of patients. This evidence concerns the gene IL2 and liver cancer.