Study Of The Expression Of P73α And 14-3-3σ In The Benign And Malignant Tissues Of Breast And The Relationship Between Their Expression And The Clinical Biological Behaviour

Objective: Breast cancer is one malignant tumor which threatened the health of women. According to statistics, there are about 1200,000～1400,000 new breast cancer cases every year all over the world, and 500,000 of them died from it. Recent years, the incidence of breast cancer in China had increased by 3% every year. Studies showed that, carcinogenesis and development of breast cancer had multiple steps and was the results of the function of multiple genes. With the increasing of the incidence of breast cancer, it becomes one hot issue in the oncology field to study the susceptibility gene and correlative gene and its product. We detected the expression of carcino-suppression gene p73αand a negative regulation factor of cell cycle 14-3-3σin the normal breast tissues, tissues besides tumor and tumor tissues on the transcriptional and protein level by using Reverse transcription- polymerase chain reaction and Streptavidin peroxdase conjugated method; Together with the retrospective analysis of the correlation of the expression of p73αand 14-3-3σin the breast cancer tissue and their clinicobiological behaviour, we anticipated to provede a new molecular biological index and target to the early discovery and targeted therapy of breast cancer.Methods: Detect the expression and interaction of anti-oncogene p73αand the negative regulation factor of cell cycle 14-3-3σin the normal breast tissues, tissues besides tumor and tumor tissues on both transcriptional and protein level by using reverse transcription-polymerase chain reaction and streptavidin peroxdase conjugated method. And retrospectively analyze the relationship between the expression of p73α, 14-3-3σand the clinical biological behavior including tumor size, TNM stages, pathological types, histology grades, metastasis of axillary lymph nodes, haemal tube tumor embolus, ER/PR and HER-2.Results:1 Expression of p73αin the normal breast tissues, tissues besides tumor and tumor tissues1.1 Expression of p73αon the mRNA levelp73αwas positively expressed in 25 of 33 normal breast tissue (75.8%); 22 of 33 were positively expressed in the tissues besides tumor (66.7%), and 20 of 33 were positively expressed in the tumor tissues (60.6%). The rectificational value of p73α(p73/GAPDH)in the normal breast tissues, tissues besides tumor and tumor tissues were respectively 0.8378±0.5921,0.9199±0.8441 and 0.6150±0.3756, and no significant difference was found among the three groups (F=1.139,p=0.326). 1.2 Expression of p73αon the protein levelp73αprotein was positively expressed in 25 of 33 normal breast tissue (75.8%); 30 of 33 were positively expressed in the tissues besides tumor (90.9%), and 10 of 33 were positively expressed in the tumor tissues (30.3%). Significant difference was found between the tumor tissues and tissues besides tumor or normal tissues (χ2=17.860, p=0.000;χ2=8.726, p=0.003), and no significant difference was found between the tissues besides tumor and the normal breast tissues (χ2=3.385, p=0.066).2 Expression of 14-3-3σin the normal breast tissues, tissues besides tumor and tumor tissues2.1 Expression of 14-3-3σon the mRNA level14-3-3σwas expressed in all the 33 normal breast tissues; 32 of 33 were positively expressed in the tissues besides tumor (97.0%), and were positively expressed in all the 33 tumor tissues (100%). The rectificational value of 14-3-3σ(14-3-3σ/ GAPDH)in the normal breast tissues, tissues besides tumor and tumor tissues were respectively 2.8231±0.1973,2.1950±0.1864 and 1.4680±0.0840, and no significant difference was found between the tumor tissues and tissues besides tumor, and between the tissues besides tumor and the normal breast tissues (p=0.075, p=0.123); The expression of 14-3-3σin the tumor tissues were much lower than that of the normal breast tissues, and significant difference was found (F=5.640, p=0.005).2.2 Expression of 14-3-3σon protein level14-3-3σprotein was strongly positively expressed in 18 of 33 normal breast tissue (54.5%); 11 of 33 were strongly positively expressed in the tissues besides tumor (33.3%), and 6 of 33 were strongly positively expressed in the tumor tissues (18.2%).The expression level of 14-3-3σprotein was negatively correlative with the cellular proliferation (r=-3.093, p=0.003); And significant differences were found between the normal breast tissues and tumor tissues(χ2=14.029, p=0.000), between tissues besides tumor and tumor tissues (χ2=6.344, p=0.012), but no significant difference was found between the normal breast tissues and tissues besides tumor (χ2=2.752, p=0.097).3 Relationships between the expression of p73αprotein and the clinical parameters16.7% (4/24) were p73αpositive in the haemal tube tumor embolus group; and 40.4% (21/52) were p73αpositive in the no haemal tube tumor embolus group, and significant difference was found (χ2=4.185, p=0.034). In the patients of positive expression of ER and PR, the positive rate of p73αwas 72.7% (16/22); and in the patients of negative expression of ER and PR, the positive rate was 33.3% (8/24); and only one was positively expressed in the group of positive expression of ER but negative expression of PR or negative expression of ER but positive expression of PR, the rate was 3.3% (1/30). Significant differences were found in every two groups (χ2=27.692, p=0.007). Relationships between the protein expression of p73αand the other clinical parameters: no significant correlation were found between the p73αexpression and clinical stages (χ2=0.217, p=0.887),metastasis of axillary nodes (χ2=0.007, p=0.564),numbers of metastasis of axillary nodes (χ2=0.002, p=0.579),tumor size (χ2=0.953, p=0.329),pathological types (χ2=1.907, p=0.167) histology grades (χ2=0.02, p=0.888) and the over-expression of HER-2 (χ2=1.931, p=0.126).4 Relationships between the protein expression of 14-3-3σand the clinical parametersPositive rate of 14-3-3σprotein expression decreased along with the increase of the histology grades, and negative correlativity was found between them (γ=-0.369,χ2=6.133, p=0.013); In the group whose HER-2 was hyper-expressed (more than ++), the strong positive rate was 16.8% (8/48), and in the group whose HER-2 was hypo-expressed, the rate was 44.4% (12/28), and significant difference was found (χ2=6.173,p=0.014); No significant differences were found between the expression of 14-3-3σand pathological types (χ2=1.462, p=0.227), metastasis of axillary nodes (χ2=1.373, p=0.179), number of the metastasis of axillary nodes (χ2=0.468, p=0.349),haemal tube tumor embolus or not (χ2=1.684, p=0.154) , tumor size (χ2=1.317, p=0.251), clinical stages (χ2=0.079, p=0.779) and ER/PR (χ2=0.044, p=0.834).5 Relationship between 14-3-3σand p73αin the p53 gene mutation breast cancer45 of 76 breast cancers were p53 positively expressed (59.2%). In the 45 breast cancer patients, the rate of both p73αand 14-3-3σpositively expressed was 61.1% (11/18), and the rate of both p73αand 14-3-3σnegatively expressed was 78.6% (22/28), positive correlativity was found(r=0.384,χ2=6.490, p=0.013).6 Relationship between the protein expression of p53 and p73αin the breast cancer tissuesPositive rate of p73αwas 42.2% (19/45) in the p53 positive group, and the rate was only 19.4% (6/31) in the p53 negative group, and they were positive correlation (r=0.239,χ2=4.919, p=0.027).Conclusions:1 p73αprotein was more hyper-expressed in the normal breast tissues and tissues besides tumor than in the tumor tissues, and negative correlation was found between the hyper-expression of p73αprotein and the haemal tube tumor embolus of the tumor tissues, especially in the patients whose ER and PR were all positive. It indicated that as an anti-oncogene, the attenuation of p73αexpression had something to do with the formation and development of breast tumor.2 The negative regulation factor of cell cycle 14-3-3σhad an attenuation tendency in the course from normal breast tissues to hyperplasia and to cancerization, and it was negative correlation with the histology grades and HER-2, Which indicated that it maybe an important suppressor factor in the carcinogenesis and development of breast cancer.3 Hyper-expression of p53 protein and the expression of p73αgene were positive correlation, and positive correlation was also found between the expression of p73αand 14-3-3σgene in the p53 gene mutated breast cancer tissues, which indicated that when p53 gene mutated, the expression of p73αgene increased to replace p53 to up-regulated the downstream factor 14-3-3σto exert the function of restraining the cell proliferation.