IL4 and breast cancer: In contrast, exosomes isolated from 4T1 breast cancer cells delivering a miR-33 mimic into IL-4 induced M2 macrophages converted them to the M1 phenotype as indicated by an increase in expression of M1 markers, including IRF5, NOS2, and CD86, and a decrease in M2 markers including ARG, Ym1, and CD206.