ABCG2 and breast cancer: Acetylenic oxylipins of the falcarinol-type have, for example, shown to bind covalently to the efflux protein ABCG2 (also known as the breast cancer resistance protein (BCRP)) involved in breast cancer chemotherapy resistance [17] as well as to the cannabinoid receptor 1 (CB1) and GABAA receptors resulting in modulation of the activity of these receptors [15,18].