Expression Of BCRP, MRP2 And Sorcin And Their Relations With Prognosis In Breast Cancer

Objective To examine expression of BCRP, MRP2, Sorcin and to investigate the relationship between the expression and prognosis on protein and mRNA levels in primary breast cancer patients. Methods BCRP, MRP2 and Sorcin mRNA and protein levels were determined with reverse transcription polymerase chain reaction (RT-PCR) in samples of 30 primary breast carcinomas and with immunohistochemistry (IHC) in 60 primary breast cancer patients. Expression of BCRP, MRP2 and Sorcin in the tumors were studied on (i) relations with disease-free survival (DPS) and overall survival (OS), (ii) relations to clinicopathological factors, (iii) their expression diversity between primary tumors and axillary metastatic lymph nodes,(iv) their expression correlations between each other. Results Results obtained by both methods were almost concordant. (i) Expression of BCRP and MRP2 in breast cancer specimens were markedly higher than those in the normal breast tissue on mRNA levels, (ii) The carcinoma which negatively expressed BCRP seemed to have a longer DPS than those expressed positively. No relation can be established between expression of BCRP and other clinicophathological parameters, (iii) Through Cox multivariate regression analysis, we found that tumor size , axillary lymph node numbers, ER status showed significant associations with shorter DFS or OS; PR status showed significant associations with shorter OS. (iv) There was no relationship between expression of BCRP and MRP2 with clinicopathological factors on mRNA levels. But Sorcin expression was more frequently observed in patients under 50 years old. IHC analysis showed an association between BCRP expression and positive axillary nodes, ER and PR status, (v) There were positive correlations between BCRP and MRP2, BCRP and Sorcin, P-gp and MRP1 on proteinlevels, (vi) There was no significant difference in expression of BCRP, MRP2 or Sorcin between the primary and metastatic sites. Conclusion Expression of BCRP and MRP2 in breast cancer specimens were markedly higher than those in the normal breast tissue on mRNA levels. Expression of BCRP was correlated with shorter DPS in breast cancer patients. Sorcin expression was more frequently observed in patients under 50 years old. IHC analysis showed an association between BCRP expression and positive axillary nodes, ER and PR status. There were positive correlations between BCRP and MRP2, BCRP and Sorcin, P-gp and MRP1 on protein levels. The BCRP, MRP2 and Sorcin expression in metastatic lymph nodes may no reflect an aggressive biologic behavior in breast cancer.