The Expression Of P53in Different Breast Cancer Molecular Subtypes And The Relationship Between P53with Drug Resistance Proteins

Objective:This study explored the expression and significance of the p53in different breast cancer molecular subtypes,and discussed the relationshipbetween p53and drug resistance proteins,that could provide more theoreticalbasis for application of p53in breast cancer molecularclassification.Methods:We collected ER,PR,Her-2and Ki-67of postoperativehistopathologic examination in every patient,and divided breast cancer patientsinto four molecular subtypes including Luminal A subtype,Luminal Bsubtype,Her-2over-expression subtype and Basal-like subtype by St.Gallenclassification rules.Then we selected50patients in every subtype completelyrandom,that were altogether200cases.We collected some kinds of pathologicaldata including tumor sizes,lymph node metastases,histological types and WHOhistological grades of these patients,then analyzed the pathologicalcharacteristics of every subtype.We got the p53, Pgp、GSTπ、Topo Ⅱproteinexpression status in200breast cancer patients including four molecularsubtypes by immunohistochemical SP method,then we analyzed expressionstatus of these protein and the relationship between p53and drug resistanceproteins.Results:1.We found there were statistically significanct（P<0.05） intumor sizes,lymph node metastases,histological subtypes and WHO histologicalgrades among four breast cancer molecular subtypes.2.After detecting p53 positive rate in each molecular subtype,we found Luminal A subtype was30.0%,Luminal B subtype was22.0%,the p53positive rate of Her-2over-expression subtype and Basal-like subtype was higher than two subtypesbefore,they was48.0%and46.0%each other,the difference was statisticallysignificant（P<0.05）.3.Pgp positive rate was54.0%,34.0%,32.0%and28.0%each other in Luminal A subtype,Luminal B subtype,Her-2over-expressionsubtype and Basal-like subtype.The difference was statistically significant（P<0.05）.GSTπ positive rate was60.0%,44.0%,10.0%and40.0%each otherin four molecular subtypes.The difference was statistically significant（P<0.01）.In four subtypes,Ⅰ-Ⅱ grade expression of Topo Ⅱ proteinwas84.0%,94.0%,80.0%,86.0%each other，Ⅲ-Ⅳ grade expression of TopoⅡprotein was16.0%,6.0%,20.0%,14.0%each other,their differences weren’tsignificant（P>0.05）.4.In Luminal A subtype and Luminal B subtype,Pgppsitive rate and GSTπ positive rate of p53(+) group was80.0%and86.7%eachother in the former subtype, that was63.6%and72.7%each other in the lattersubtype,these protein positive rate was higher than p53(-) group,and thedifference was statistically significant(P<0.05).In two Luminal subtypes,therewasn’t statistically significant difference between p53(+) group and p53(-)group in TopoⅡ protein positive expression status(P>0.05).In Her-2over-expression subtype and Basal-like subtype,there weren’t statisticallysignificant difference between p53(+) group and p53(-) group in Pgp,GSTπ andTopoⅡ protein positive expression status(P>0.05).Conclusion:1.Differentbreast cancer molecular subtypes have different clinicopathological characteristics,Luminal subtype is more likely to early TNM stage,highdifferentiation and low malignancy,Her-2over-expression subtype andBasal-like subtype are converse.2.It is possible that p53exists differentialexpression in different breast cancer molecular subtypes.3.It is possible thatPgp and GSTπ exists differential expression in different breast cancer molecularsubtypes.4.It found a positive correlation between the expression of p53andPgp,GSTπ in Luminal A and B subtype.5.P53that detects byimmunohistochemical method can be applied to breast cancer molecularclassification for assessment of clinical and pathological characteristics andjudgement of chemotherapy sensitivity in every molecular subtypes. Thedetection of p53is easy and feasible, the molecular diagnosis and therapy ofbreast cancer can get better development through the application of p53,so thatwe can treat breast cancer individually.We think that p53possess good clinicalapplication value.