Breast Cancer Resistance Protein (BCRP) is a type of protein that plays a crucial role in the body's defense against certain drugs and toxins. It is part of the ATP-binding cassette (ABC) transporter family, which helps transport various substances across cell membranes. BCRP is particularly important in the context of cancer treatment, as it can affect the effectiveness of chemotherapy drugs by pumping them out of cancer cells, leading to drug resistance. BCRP is found in various tissues, including the intestines, liver, and blood-brain barrier. Its expression can vary among individuals, influencing how well certain medications work. Understanding BCRP's function is essential for developing strategies to overcome drug resistance in cancer therapies, potentially improving treatment outcomes for patients with breast cancer and other malignancies.