The article discusses the role of ATP-dependent transporters in multidrug resistance (MDR) in cancer. MDR is a significant challenge in chemotherapy, as it allows cancer cells to become resistant to multiple drugs. The cellular mechanisms of MDR are categorized into two main classes: impaired drug delivery and genetic/epigenetic alterations within the cancer cells. Impaired drug delivery can result from poor absorption, increased metabolism, or excretion, leading to reduced drug levels in the blood and diffusion into the tumor mass. Environmental factors, such as the tumor vasculature and geometry, also play a role in drug resistance. Genetic and epigenetic alterations, including the expression of ATP-dependent efflux pumps like PGP (ABCB1 or MDR1), can affect drug sensitivity. PGP is a broad-spectrum multidrug efflux pump with 12 transmembrane regions and two ATP-binding sites. Other ABC transporters, such as MRP1, MRP2, and ABCG2 (BCRP), also contribute to MDR. These transporters can pump drugs out of cells, reducing their intracellular accumulation and effectiveness. The article highlights the importance of understanding these mechanisms to develop strategies to overcome MDR, such as using PGP inhibitors. However, the clinical efficacy of PGP inhibitors has been challenging due to pharmacokinetic interactions and the need for more specific inhibitors. Future prospects include predicting drug resistance based on molecular markers and preventing the emergence of resistance by increasing intracellular drug concentrations early in treatment.The article discusses the role of ATP-dependent transporters in multidrug resistance (MDR) in cancer. MDR is a significant challenge in chemotherapy, as it allows cancer cells to become resistant to multiple drugs. The cellular mechanisms of MDR are categorized into two main classes: impaired drug delivery and genetic/epigenetic alterations within the cancer cells. Impaired drug delivery can result from poor absorption, increased metabolism, or excretion, leading to reduced drug levels in the blood and diffusion into the tumor mass. Environmental factors, such as the tumor vasculature and geometry, also play a role in drug resistance. Genetic and epigenetic alterations, including the expression of ATP-dependent efflux pumps like PGP (ABCB1 or MDR1), can affect drug sensitivity. PGP is a broad-spectrum multidrug efflux pump with 12 transmembrane regions and two ATP-binding sites. Other ABC transporters, such as MRP1, MRP2, and ABCG2 (BCRP), also contribute to MDR. These transporters can pump drugs out of cells, reducing their intracellular accumulation and effectiveness. The article highlights the importance of understanding these mechanisms to develop strategies to overcome MDR, such as using PGP inhibitors. However, the clinical efficacy of PGP inhibitors has been challenging due to pharmacokinetic interactions and the need for more specific inhibitors. Future prospects include predicting drug resistance based on molecular markers and preventing the emergence of resistance by increasing intracellular drug concentrations early in treatment.