The ABC transporter proteins ABCB1 (MDR1/P-glycoprotein), ABCC1, and ABCG2 permit the transmembrane transport of different substrates, including chemotherapeutic agents; thus, they are implicated in multidrug resistance (MDR) in different types of tumors, such as lung cancer—reviewed in [92]. This evidence concerns the gene ABCG2 and lung carcinoma.