ABCG2 and cancer: Therefore, there is still a need for further studies concerning the modulation of ABC transporters by phytochemicals to clarify which ones are suitable as co-adjuvants and also concerning the role of the patient’s diet in the interaction between therapeutic drugs and the intestinal barrier, the ultimate goal being a balance between xenobiotic export for homeostasis maintenance and drug uptake and bioaccumulation into cancer cells for optimal therapeutic purposes.