ABC transporters are transmembrane proteins that enable translocation of various substances across cellular membranes, and as such are essential in maintaining integrity and homeostasis of whole metabolism. These proteins are composed of multiple domains, and interactions between domains and their conformational changes are crucial in translocation process. These transbembrane proteins utilize energy by hydrolysis of ATP, which causes a conformational change. ABC gene family are classified based on domain homology into seven subfamilies. Different ABC transporter proteins perform different functions in the body and are present in different cells and tissues of the body. Different types of ABC transporters are responsible for the transfer of substrates with heterogeneous structure, origin and function in the cell. Although they participate in the transfer of endogenously synthesized substrates and the foreign substances, they were primarily discovered because of their role in the removal of anticancer drugs from tumor cells thereby reducing the efficiency of tumor ttreatment. Efficiency of the treatment of tumors affects other than drugs, and other factors such as cell physiological condition and polymorphisms of ABC transporters. Different genetic variant coding for a particular protein affect its conformation and the possibility of maintaining its function in cells. Research based on various malignancies in humans has shown that different gene variants of ABC transporters affect outcomes - either increase or decrease treatment efficiency. Further research should contribute to understanding polymorphisms in ABC transporters and their function in translocation mechanisms across the membrane and thus allow better understanding and more efficient treatment of malignant diseases.