Studies of Hodgkin lymphoma identified a pro-tumoral role of IL-9 in IL-9R-expressing target cells.55 Similarly, our studies revealed that tumour cells in experimental colorectal neoplasias exhibited a higher IL-9R expression that controls IECs, suggesting that tumuor cells are sensitive to IL-9-mediated signal transduction. This evidence concerns the gene IL9 and Hodgkins lymphoma.