P-glycoprotein and MRP1 expression in axillary lymph node metastases of breast cancer patients.
BACKGROUND
Only little information on the expression of P-glycoprotein (P-gp) and MRP1 in metastases of breast carcinomas is currently available. The aim of the present study was to investigate the expression of these two proteins in axillary lymph node metastases of breast cancer patients.


METHODS
We determined the expression of P-gp and MRP1 in axillary lymph node metastases of 63 breast cancer patients and, in 32 patients, compared this expression to the expression of corresponding primary tumors. P-gp was detected by means of C219 and Ab-2 monoclonal antibodies, and MRP1 by means of the MRPr1 monoclonal antibody.


RESULTS
In lymph node metastases, P-gp expression was positive, usually at low levels, in 28 (44%) specimens whilst MRP1 expression was positive in all specimens with low, intermediate and high levels in 3 (5%), 46 (73%) and 14 (22%) specimens, respectively. The percentage of P-gp expression was slightly lower in lymph nodes than in primary tumors while MRP1 expression showed a higher staining intensity in lymph nodes than in their corresponding primary tumors.


CONCLUSIONS
These data indicate that both P-gp and MRP1 are frequently expressed in lymph node metastases of breast cancer patients and that MRP1 expression is more pronounced in lymph node metastases than in corresponding primary tumors.
Zöchbauer-Müller
S
S
Division of Oncology, Department of Internal Medicine I, University of Vienna Medical School, Währinger Gürtel 18-20, A-1090 Vienna, Austria.
Filipits
M
M
Rudas
M
M
Brunner
R
R
Krajnik
G
G
Suchomel
R
R
Schmid
K
K
Pirker
R
R
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D001365:Axilla; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D002277:Carcinoma / Q000378:metabolism* / Q000556:secondary; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000378:metabolism* / Q000473:pathology; D008207:Lymphatic Metastasis; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D000074081:MutS Homolog 3 Protein
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D004268:DNA-Binding Proteins; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D000074081:MutS Homolog 3 Protein; C078444:MSH3 protein, human; C421109:multidrug resistance-associated protein 1