Among other cytokines associated with the Th2 profile, IL-4 has been shown to induce polarization of macrophages to M2 type with immunoregulatory, anti-inflammatory and tumor-promoting activity [57, 58], coherent with prior findings evidencing association between a cytokine hypoproducing phenotype, like IL-6 (OR = 4.8; P = 0.002), and the existence of malignant brain tumor, added to the significantly higher expression of the − 1082 (AA) phenotype, IL-10 hypoproducer, in the group of patients with benign neoplasia (OR = 8.0; P < 0.001) [16]. This evidence concerns the gene IL6 and neoplasm.