Multidrug resistance in locally advanced breast cancer

Atalay, Can
Gurhan, Ismet Deliloglu
Irkkan, Cigdem
Gündüz, Ufuk
Background: Advanced breast cancer cases can still be encountered resulting in poor prognosis. The primary treatment for these patients is chemotherapy, and multidrug resistance (MDR) is a serious obstacle in the treatment. Detecting drug resistance before first-line chemotherapy may increase the patient's survival. In this study, the role of MDR is evaluated in locally advanced breast cancer patients. Methods: Reverse transcriptase polymerase chain reaction was used for the detection of MDR genes, ABCB1 and ABCC1. Immunohistochemistry was used for the detection of MDR proteins, P-glycoprotein (Pgp) and MDR-associated protein 1. Results: Breast tissues from 25 patients both before and after chemotherapy were examined. Five patients were unresponsive to chemotherapy. Four had ABCB1 gene expression induced by chemotherapy, and Pgp positivity was detected in 9 patients after chemotherapy. Both the induction of ABCB1 gene expression (p < 0.001) and Pgp positivity (p < 0.001) during chemotherapy were significantly related with clinical response. Although 80% of the clinically unresponsive patients had ABCC1 gene expression, the relation between ABCC1 expression and clinical drug response was not significant. Conclusion: In locally advanced breast cancer, ABCB1 gene expression during chemotherapy contributes to clinical unresponsiveness. However, ABCC1 gene expression did not correlate strongly with the clinical response. Copyright (c) 2006 S. Karger AG, Basel


Multidrug Resistance Mediated by MRP1 Gene Overexpression in Breast Cancer Patients
Abaan, Ogan Demir; Mutlu, Pelin; Baran, Yusuf; Atalay, Can; Gündüz, Ufuk (2009-01-01)
Multidrug resistance (MDR) is a serious handicap towards the effective treatment of breast cancer patients. One of the most prevalent MDR mechanisms is through the overexpression of genes coding the proteins called Multidrug Resistance-associated Proteins (MRPs). The aim of this study was to investigate the expression of MRP1 in tumor tissues from breast cancer patients. In this study, a semi-quantitative RT-PCR approach was utilized. Our results suggest that MRP1 overexpression can mediate MDR in patients....
Multidrug resistance in logally advanced breast cancer
Atalay, Mustafa Can; Gündüz, Ufuk; Department of Biotechnology (2004)
Breast cancer is the most frequently detected cancer among women. Early diagnosis leads to long term survival when the patients are treated with surgery, radiotherapy, chemotherapy, and hormone therapy. Unfortunately, advanced disease could still be encountered in some patients resulting in a poorer prognosis. The primary treatment modality is chemotherapy for this group of patients. Drug resistance is a serious problem resulting in the use of different drugs during chemotherapy and knowing the possibility ...
Targeting HIF1-alpha/miR-326/ITGA5 axis potentiates chemotherapy response in triple-negative breast cancer
Assidicky, Ridho; Tokat, Unal Metin; Tarman, Ibrahim Oguzhan; Saatci, Ozge; Ersan, Pelin Gulizar; Raza, Umar; Ogul, Hasan; Riazalhosseini, Yasser; Can, Tolga; Sahin, Ozgur (2022-03-01)
Purpose Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer that is frequently treated with chemotherapy. However, many patients exhibit either de novo chemoresistance or ultimately develop resistance to chemotherapy, leading to significantly high mortality rates. Therefore, increasing the efficacy of chemotherapy has potential to improve patient outcomes. Methods Here, we performed whole transcriptome sequencing (both RNA and small RNA-sequencing), coupled with network simu...
Overexpressed genes/ESTs and characterization of distinct amplicons on 17q23 in breast cancer cells
Erson Bensan, Ayşe Elif; DEMERS, SK; ROUILLARD, JM; HANASH, SM; PETTY, EM (Elsevier BV, 2001-11-01)
17q23 is a frequent site of gene amplification in breast cancer. Several lines of evidence suggest the presence of multiple amplicons on 17q23. To characterize distinct amplicons on 17q23 and localize putative oncogenes, we screened genes and expressed sequence tags (ESTs) in existing physical and radiation hybrid maps for amplification and overexpression in breast cancer cell lines by semiquantitative duplex PCR, semiquantitative duplex RT-PCR, Southern blot, and Northern blot analyses. We identified two d...
Alqudah, Ali Mohammad; Algharib, Huda M. S.; Algharib, Amal M. S.; Algharib, Hanan M. S. (2019-02-01)
Breast cancer is the most frequent cancer type that is diagnosed in women. The exact causes of such cancer are still unknown. Early and precise detection of breast cancer using mammogram images or biopsy to provide the required medications can increase the healing percentage. There are much current research efforts to developed a computer aided diagnosis (CAD) system based on mammogram images for detecting and classification of breast masses. In this research, a CAD system is developed for automated segment...
Citation Formats
C. Atalay, I. D. Gurhan, C. Irkkan, and U. Gündüz, “Multidrug resistance in locally advanced breast cancer,” TUMOR BIOLOGY, pp. 309–318, 2006, Accessed: 00, 2020. [Online]. Available: