Poster Presenter

Link Betweeen Multidrug Resistence-Related Proteins And Histo-Pathological Features In Breast Cancer.
S. Rybárová, I. Hodorová, Vecanová, J. Slovak Republic.
Slovakia

The aim of this work was to determine the expression of the multidrug resistance (MDR) proteins, namely MDR1 (P-glycoprotein), MRP1 (multidrug resistance-related protein) and LRP (lung resistance related protein) in breast carcinoma.

Detection of these proteins was provided in 87 samples of breast cancer by using of indirect enzymatic immunohistochemistry. Our findings were compared with other clinical and pathological parameters, as are: expression of Her2/neu, estrogen (ER) and progesteron (PR) receptor status, histological grade and regional lymph node status. For statistical anlysis, non-parametric two sided Mann-Whitney - U - test was used.

Majority of breast carcinoma specimens show the positivity for these proteins. The MDR1 and MRP1 signal was found in the cytoplasm od cancer cells. The expression of LRP was found in the cytoplasm close to the nuclear membrane. The samples were positive for MDR1 protein in 57%, for MRP1 in 84% and for LRP in 79%. In comparison of our results with other clinical and pathological parameters, the negative correlation between ER, PR and MDR1 expressions and histological grading status was found. No associations were observed between the two proteins and histological grading, as well as between the expression of all three proteins and other clinicaly relevant parameters.

In conclusion, high frequency of expression of MDR proteins in breast carcinoma cells suggests, that these proteins might be an important factor of drug resistance in breast cancer. Nevertheles, the negative correlation between the histological grade of malignancy of tumor and the expression of ER, PR and MDR1 indicates the possible influence of progressive tumor cell dediferentiation. However, this findings has to be confirmed in additional evaluations.

We are grateful to League Against Cancer of Slovak Republic for generous finantial support of our work. This study was also supported by the VEGA grant 1/0388/08.

References:

1. Burcombe RJ, Makris A, Richman PI , Daley FM, Noble S, et al.: Evaluation of ER, PgR, Her-2 ans Ki-67 as predictors of response to neoadjuvant anthracycline chemotherapy for operable breast cancer. Br. J. Cancer 2005, 92: 147-155.

2. Larkin A, O´Driscoll L, Kennedy S, Purcell R, Moran E, et al.: Investigation of MRP-1 protein and MDR-1 P-glycoprotein expression in invasive breast cancer: a prognostic study. Int. J. Cancer 2004, 112: 286-294.

3. Li EX, Li Y, Yang J, He J, Chen L, et al.: Influence of P-glycoprotein expression on chemotherapeutic response of metastatic breast carcinoma. Ai Zheng 2002, 21: 430-432.