Akademik Veri Yönetim Sistemi
HEALTH PROBLEMS OF CIVILIZATION, cilt.19, sa.2, ss.148-162, 2025 (ESCI)
Background. During cancer therapy, resistance to chemotherapeutic agents is common and
often linked to multidrug resistance mechanisms. Glutathione S-transferases (GSTs) and ATPbinding cassette (ABC) transporters, including multidrug resistance (MDR) proteins, multidrug
resistance-associated proteins (MRPs), and breast cancer resistance protein (BCRP), are
implicated in drug resistance.
Material and methods. Protein expressions were determined in the tumor and surrounding
tumor free breast tissues of 145 breast cancer patients by immunohistochemistry technique.
Among 145 patients, 50 received preoperative (neoadjuvant) chemotherapy, and 95 received
postoperative (adjuvant) chemotherapy.
Results. In 50 neoadjuvant breast cancer patients, GSTA1, GSTK1, GSTM1, GSTO1, GSTP1,
GSTS1, GSTT1, GSTZ1, MDR1, MRP1, MRP2, MRP3, MRP7, and BCRP expressions were
higher in tumor epithelium compared to normal epithelium (p<0.05). In 95 adjuvant breast
cancer patients, GSTA1, GSTK1, GSTM1, GSTP1, GSTT1, GSTZ1, MDR1, MRP1, MRP2,
and MRP3 expressions were higher in tumor epithelium than in normal epithelium (p<0.05).
GSTP1, GSTT1, and MRP3 expressions were significantly higher in neoadjuvant compared to
adjuvant-treated breast cancer patients’ tumor tissues (p<0.05). Conclusions. GSTP1, GSTT1, and MRP3 may be important in inactivating the
chemotherapeutic agents used in platinum-based treatment and are thus responsible for the drug
resistance in breast cancer patients.
Keywords: multidrug resistance, GST, drug resistance, breast cancer, chemotherapy