Expression and significance of CDC6 in breast cancer tissues

OBJECTIVE:To determine the expression of cell division cycle 6(CDC6)in breast cancer(BC)and investigate its relationship to HER-2/neu gene amplification and clinical significance.METHODS:Totally 315primary BC cases diagnosed in Tianjin Medical University Cancer Institute and Hospital were selected in this study,including 120cases with HER-2/neu FISH results from January 1to March 31of 2013and 195cases with long-term follow-up(30lobular hyperplasia cases during the same time were selected as control group)from January 1to April 30of 2005.The expressions of CDC6were detected by immunohistochemistry(IHC).We analyzed relationship of CDC6expression to HER-2/neu gene amplification and its effect on clinicopathological characteristics and prognosis for BC patients.RESULTS:In 120IDCNOS cases,25cases(20.8%)had CDC6negative expression and 95cases(79.2%)had CDC6positive expression;In CDC6negative and positive groups,12cases(48.0%)and 74cases(77.9%)had HER2/neu gene amplification.CDC6was positively correlated with HER2/neu gene amplification(r=0.242,P=0.008).Among 22.6%(44/195)and 77.4%(151/195)of cases,CDC6had negative and positive expressions respectively.The rate of positive expression of CDC6in BC cases was significantly higher than that in Lobular hyperplasia cases(60.0%,P=0.040).CDC6expression was found to be associated with unfavorable features of BC patients,including tumor size(P=0.025),histological grade(P=0.021),pTNM stage(P=0.023),HER2/neu expression(P=0.022)and Ki-67expression(P=0.003).The expression of CDC6was negatively correlated with disease-free survival(DFS)time(P=0.020).CONCLUSIONS:CDC6is a protein associated with HER2/neu amplification and expression,its expression is related to cell proliferation and poor prognosis in BC patients.Therefore CDC6is expected to become a new target for breast cancer therapy.