IL9 and cancer: They are also critical drivers of allergy-associated pathologies, like allergic asthma and atopic dermatitis and associated eosinophilia and are seen in the TME of different cancers (Figure 3), such as breast cancer, where their anticancer action is governed by liver X receptor (LXR) activation in response to oxidized cholesterol, which inhibits IL-9 expression, which in turn inhibits Tc9 differentiation and function [222,224,225,226].