Indeed, the H&E staining revealed that more than 30% of tumour area in the IL4‐treated C26‐bearing mice (sacrificed at Day 31 after C26 cell injection) was necrotic (eosin positive) probably surrounded by small inflammatory cell infiltrate, a pattern that could not be observed in tumours isolated from C26 hosts (Day 13 after C26 implantation; Figure3A and 3B).24 A possible limitation of these results is that the histological analysis compares Day 13 C26 with Day 31 C26 + IL4 tumours. This evidence concerns the gene IL4 and neoplasm.