Preliminary Study Of Biological Characteristics And Survival Analysis Of Luminal B Breast Cancer

Background and ObjectiveBreast cancer is now accounte for the first female lethal tumor in the most common malignant tumors in women. In recent years, the incidence of breast cancer in China is still rising with the annual growth rate is about3%to4%, and the age at iiagnosis is becoming younger and younger.Conventional diagnosis of breast cancer only relied on the microscopic findings, ind not be further broken down. The treatment method was substantially similar. With the rapid development of molecular biology in the mRNA levels of gene expression analysis, distinct molecular subtypes of breast cancer had uncovered These subtypes include HER2-enriched, basal-like, normal-like, luminal B and luminal A. The12th St Gallen International Breast Cancer Conference determined a new molecular classification criteria in the genetic level, divided breast cancer into four subtypes, including:Luminal A type of breast cancer (ER+and/or PR+, HER-2-, Ki-67+<14%), Luminal B type breast cancer (ER+and/or PR+, HER-2+and/or Ki-67+≥14%), HER-2positive breast cancer (ER-, PR-, HER-2+), triple negative breast cancer (ER-, PR-, HER-2-). This subtyping method maked the installments of luminal B breast cancer more reasonable, and could be a good solution to the heterogeneity of the tumor, the accuracy of the prognosis, and also provided an important basis for individualized treatment of breast cancer. The high expression of HER2and Ki-67in luminal B breast cancer makes it more resistant to endocrine therapy and has a poorer clinical prognosis and other aggressive characteristics compared with luminal A breast cancer. The purpose of this study was to research the biological characteristics of Luminal B breast cancer and compare the differences with the other three subtypes of berast cancer. Also, the survival analysis of luminal B breast cancer was studied in this study to provide some reference value in the future clinical understanding and individualized treatment of luminal B breast cancer.Material and method1ObjectiveThis study cllected544patients with breast cancer who have complete clinical and pathological data in the breast surgery department of the First Affiliated Hospital of Zhengzhou University. The youngest was25years old and the oldest was79years old, with a median age of48years old.2CriteriaAll biopsys were reviewed. Selected10randomly high-power field, and then counted the number of positive cells per field and averaged. Pathological staging and tumor grade and stage were according to the NCCN guidelines while Molecular subtypes judgment was according to the consensus of the12th St. Gallen International Breast Cancer Conference. Menopause standard was based on the2010version of the NCCN judgment.3Statistical AnalysisAll statistical analysis were performed using the SPSS version17.0statistical package for Microsoft. Pearson’s χ2test was used to evaluated the significance of differences between designated groups. Using Cox regression model for multivariate analysis and Kaplan-Meier method for survival analysis. α is0.05as the size of test.Result1Comparison Clinical Pathology Features of Different SubtypesThe namber and the rate of Luminal B, Luminal A, HER-2positive and Triple negative breast cancer were291(53.5%),102(18.8%),84(15.4%),67(12.3%), respectively. There were no statistically significant differences among different molecular subtypes in clinical pathology features.2The Analysis of the expression of Ki-67in Luminal B Breast CancerCorrelation analysis showed that the expression of Ki-67in Luminal B breast cancer was negatively correlated with ER and PR, but positively correlated with HER-2, and there was no correlation with the patient’s menopausal status.3Univariate and Multivariate Analysis of Luminal B Breast CancerUnivariate analysis showed that histological grade and age were not important prognostic factors of Luminal B breast cancer, but the size of the tumor and lymph node metastasis were prognostic factors. The Cox proportional hazards regression model showed that lymph node metastasis was the independent risk factor of the prognostic of Luminal B breast cancer.4Survival Analysis of the Four SubtypesThe survival analysis of different subtypes of berast cancer showed that there were no significant differences among Luminal B subtype, Luninal A subtype and triple negative subtye in both DFS rate and OS rate (5years). But the DFS rate and OS rate (5years) of Luminal B subtype was better than Her-2over-expressing subtype.ConclutionLuminal B breast cancer is the highest subtype in all of the four subtypes of breast cancer and there are no statistically significant differences in pathological features among the different subtypes. The expression of Ki-67is correlated with ER、PR and HER-2in Luminal B breast cancer. Survival analysis showed that the prognosis of Luminal B breast cancer is better than HER-2overexpression breast cancer.