Additionally, the reports of certain peptides interacting with overexpressed plasmatic proteins, such as ATP-binding cassette subfamily B member 1 (ABCB1) [204], or displaying a more selective effect against specific cancer types, mainly attributed to the differences in membrane composition and electrochemical properties [46], point to a path that has not been fully considered for the improvement of new candidate peptides. This evidence concerns the gene ABCB1 and cancer.