The results showed that the percentage of cytotoxic lymphocytes (CD3+CD8+) and type II macrophages (CD11b+, F4/80+, CD206+) was higher in tumours from IL4‐treated than IL4‐untreated C26 hosts (cytotoxic lymphocytes: C26 = 13 ± 8%, C26 + IL4 = 25 ± 13%, Figure3C; macrophages: C26 = 27 ± 9%, C26 + IL4 = 37 ± 14%, Figure3E). Here, IL4 is linked to neoplasm.