In our study, from 46 breast cancer patients, 26 patients had negative HER-2 expression and 20 patients with positive HER-2 expression, the IL-2 levels were significantly higher in the group with positive HER-2 expression compared to negative ones (11.154 pg/mL and 7.120 pg/mL, P = 0.001). The gene discussed is ERBB2; the disease is breast cancer.