Expressions of resistance proteins P-gp,BCRP and LRP:a comparison between primary and metastatic breast carcinoma

Objective To investigate the differences in expressions of P-glycoprotein(P-gp),breast cancer drug resistance protein(BCRP) and pulmonary resistance protein(LRP) between primary breast carcinoma and metastatic lymph nodes.Methods The expressions of P-gp,BCRP and LRP in breast cancer tissues,including 126 primary carcinoma and 66 metastasis lymph nodes,were determined immunohistochemically on formalin-fixed,paraffin-embedded tumor sections.Results(1)The positive expression rates of P-gp,BCRP and LRP were 41.27%(52/126),38.89%(49/126),and 65.87%(83/126) in primary breast carcinoma,and were 59.09%(39/66),63.64%(42/66),and 60.61%(40/66) in metastatic lymph nodes,respectively.The positive rates of P-gp and BCRP in the metastatic lymph nodes were significantly higher than those in primary cancer tissue(P0.05);there was no significant difference in expression of LRP(P0.05).(2) There was a poor consistency in P-gp and BCRP expression between the primary and metastatic sites(P0.01,Kappa value were 0.276 and 0.356);there was a consistency in LRP expression between the primary and metastatic sites(P0.05).(3) The co-expression rate of two resistance proteins in primary breast carcinoma was 35.71%(45/126),of three resistance proteins was 15.08%(19/126),and of two or three resistance proteins was 50.79%(64/126),being significantly higher than that of a single protein 33.33%(42/126,P0.05).The co-expression rate of two resistance proteins in metastasis lymph nodes was 53.03%(35/66),which was significantly higher than that of a single protein 27.27%(18/66,P0.05).The co-expression rate of three resistance proteins was 16.67%(11/66),two or three resistance proteins was 69.70%(46/66),which was significantly higher than that of a single protein(P0.01).Both the co-expression levels of two resistance proteins and two or three resistance proteins in metastatic lymph nodes were significantly higher than those in primary cancer(P0.05).(4)Kaplan-Meier analyses revealed that patients with P-gp,BCRP and LRP expressed in the metastatic lymph nodes had a lower 5-year survival rate compared with patients whose primary breast cancer being positive for them.Conclusion The expression of P-gp and BCRP is different between the primary and metastatic breast cancer sites,and there is no significant difference in LRP expression.Coordination of multi-protein expression is a major feature of resistance.Metastasis lymph nodes may have a stronger resistance.