Ck5/6Protein Expression In Different Molecular Type Of Breast Cancer And Its Clinical Significance

Objective: Breast cancer has become the most malignancy in woman. Recently theincidence of Chinese breast cancer is increasing. Breast cancer is a type of highlyheterogeneous disease on molecular level. Some tumors of different patients in samepattern showed different responses to same drug treatment and different prognoses due totheir molecular genetic variant. Until now estrogen receptors (ER), progesterone receptor(PR) and C-erbB-2(human epidermal growth factor receptor-2, Her-2) were receptorsknown clearly in the carcinogenic mechanism, and became the targets for molecular drugs,These drugs have been more and more used clinically. At present, based on the results ofimmunohistological detection about the expressions of the breast cancer-associatedreceptors as ER, PR and Her-2, the cancer has been divided into Luminal A [ER (+) or PR(+) and HER-2(-)], Luminal B [ER (+) or PR (+) and HER-2(+)], HER-2expression type[ER (-),and PR (-) and HER-2(+)] and ER (-), the PR (-) and HER-2(-) type so-calledthree negative expression type. On this classification, the survival times in some patienthave been prolonged and their quality of life with has been improved. Recently threenegative expression type breast cancer is divided by the expression of CK5/6protein intotwo subtypes: basal-like cell sample type [ER (-),and PR (-) and HER-2(-) CK5/6(+)] andnormal breast-like type [ER (-), and PR (-) and HER-2(-),and CK5/6(-)]. Cytokeratin5/6called as CK5/6belongs to the high molecular weight CKs, expressing in epithelial cellsfor maintaining the morphological integrity of the epithelial cells. The patients withpositive expression of CK5/6have shorter survival time. CK5/6has been considered to beindependent prognostic for the patient with breast cancer. In this research, we detected theexpressions of CK5/6and ER, PR and HER-2immunohistologically and analyzed therelationship in CK5/6expression to the clinical pathology parameter such as age, TNMstaging, tumor size, histological type, histological grade, lymph node metastasis, nerve invasion, molecular pathological type and vascular invasion. We also analyzed therelationships among CK5/6, ER, PR, HER2and Ki67.Methods: The breast cancer tissues with clear pathological diagnosis of235patientswere collected in the hospital of Dalian from2011to2013. The protein expressions ofCK5/6, ER, PR, Ki67and HER2of the tissues were detected by immunohistochemistry.We analyzed the relationships of the CK5/6to ER, PR and HER2expressions andclinicopathological agents including the age, TNM, tumor size, node metastasis,histological grade, pathological types, invasion of vessels or nerves in the patients. We alsoanalyzed the relationships between CK5/6and molecular type of breast.Results:1. The positive expression rate of CK5/6was12.8%(30/235). The CK5/6positive expression had obviously positive correlation with histological grade. The CK5/6positive expression rate in grade3being21.4%(15/70) was significantly higher group thanthat in grade13.1%(1/32) being and grade2being10.5(14/133)(P=0.018).2. The positive expression rate of CK5/6in ER negative group being30.4%(21/69) wassignificantly higher than that in ER positive group being5.4%(9/166)(P=0.000). Thepositive expression rate of CK5/6in PR negative group being22.1%(21/95) wassignificantly higher than that in ER positive group being6.4%(9/140)(P=0.000). Thepositive expression rate of CK5/6in Ki67positive group being19.3%(21/109) wassignificantly higher than that in Ki67negative group being7.1%(9/126)(P=0.005).3.The positive expression rates of CK5/6in Luminal A, Luminal B, HER2+and threenegative expression type were3.8%(6/160),33.3%(4/12),5.9%(1/17) and41.3%(19/46)respectively. There were obvious differences among these groups (P=0.000). The positiveexpression rates of CK5/6in the three negative expression type group and Luminal B weresignificantly higher than those in the Luminal A type and HER2+type groups.Conclusion:1.The breast cancers with ER and PR expression could.hardly expressCK5/6protein.2. Some of breast cancers in Luminal B type and three negative expression type couldexpress CK5/6protein.3. The breast cancer with high proliferation could express CK5/6protein easily.4. The detection of CK5/6protein could enrich molecular pathological classification tosome extent.