Role Of Transcription Factors Ets1 And Stat3 In Regulating Angiogenesis In Breast Infiltrating Ductal Carcinoma

Objectives: To detect the expression of transcription factors Ets1, Stat3, c-Jun and the downstream proteins MMPl and HER2 in breast intraductal proliferative lesion (IPL) and infiltrating ductal carcinoma, and further investigate the role of transcription factors and the relative proteins in breast tumorigenesis. Some clues for target anti-angiogenesis therapy might expect to be obtained from this study. Methods: Immunohistochemistry and Computer-assisted image analysis system were used to detect the expression of transcription factors Ets1, Stat3, c-Jun and the downstream protein MMPl and HER2 in 152 routinely paraffin embedded specimens including 18 cases of normal breast (NB group), 20 cases of usual ductal hyperplasia (UDH group), 29 cases of atypical ductal hyperplasia (ADH group), 15 cases of ductal carcinoma in situ(DCIS group), and 70 cases of infiltrating ductal carcinoma (IDC group) . To evaluate MVD associated with the expression of these factors in different hyperplastic phases of breast intraductal epithelium and compared with clinico-pathological parameters. Results: 1. The location and expression of five proteins Etsl, c-Jun, Stat3, MMPl and HER2in IPL and IDC.(1) The location of these proteins: immunoreaction to Etsl was observed mainly in the cytoplasm and part of the nuclear of tumor cells. c-Jun was mainlyimmunostained in the nuclear of tumor cells. Stat3 was mainly stained in the nuclear and part of cytoplasm of tumor cells. MMP1 was stained in the cytoplasm of tumor cells;HER2 was stained in the membrane of tumor cells, some stromal cells were also stained by all these factors.(2) The positive expression of these proteins: Mean optical density (MOD) of positive expression of Etsl in NB, UDH, ADH, DCIS and IDC group was 0.00±0.00, 0.00±0.00, 0.06±0.04, 0.13±0.05 and 0.24±0.08 respectively. Accordingly, MOD of c-Jun was 0.00±0.00, 0.08±0.03, 0.10±0.05, 0.22±0.05 and 0.31±0.08 respectively;MOD of Stat3 was 0.05±0.00, 0.06±0.05, 0.12±0.05, 0.27±0.08 and 0.34±0.08 respectively. MOD of MMP1 was 0.03±0.01, 0.03±0.01, 0.12±0.02, 0.24±0.08 and 0.36±0.10 respectively and MOD of HER2 was 0.00±0.00, 0.00±0.00, 0.05±0.05, 0.17±0.06 and 0.31±0.10 respectively. The positive expression of Etsl, c-Jun, Stat3, MMP1 and HER2 was increasingly according to the degree of the hyperplasia of breast intraductal epithelium, in IDC exhibited a significantly increased immunoreactivity compared with IPL (P<0.001). There was no significantly difference between NB and UDH group, but the significantly differences among the other groups were found in Etsl, Stat3, MMP1 and HER2 (PO.001). The difference in every two groups was found in c-Jun (PO.001).2. Correlation between these factors in IPL and IDC(1) Correlation between Etsl and c-Jun, MMP1, HER2: In NB and UDH, no correlation was found between Etsl and c-Jun, MMP1 and HER2;In ADH, Etsl significantly correlated with c-Jun and HER2 (r=0.477 and 0.584, PO.01), while no correlation between Etsl and MMP1;In DCIS, no correlation was found inthese factors;In IDC, Etsl significantly correlated with c-Jun , MMP1 and HER2 (r=0.246, 0.548, 0.377 respectively , PO.01)(2) Correlation between Stat3 and MMP1, HER2: In NB, UDH, ADH and DCIS groups, no correlation was found between Stat3 and MMP1, HER2;while in IDC groups, Stat3 significantly correlated with MMP1 and HER2 (r=0.392, 0.307, P<0.01)o3. Correlation between these factors and MVD, VEGF in IPL and IDC: In IPL, nocorrelation was found between these factors and MVD, VEGF. In IDC, Etsl, c-Jun, Stat3, MMP1 and HER2 were all significantly correlated with MVD (r=0.57, 0.28, 0.52, 0.60 and 0.49 respectively, PO.01). Etsl, Stat3, MMP1 and HER2 were all significantly correlated with VEGF (r=0.46, 0.54, 0.31 and 0.46 respectively, PO.01 for all), while c-Jun was not related with VEGF.4. Correlation between these factors and clinico-pathological parameters in IDC group: Etsl, Stat3, MMP1 and HER2 were significantly related with histological grade, clinical stage and axillary lymph node metastasis (PO.05)Conclusions:1. In this study, we provided a series of basic parameters for study the mechanism of transcription factors Etsl and Stat3 in regulating angiogenesis in vivo in breast tumorigenesis.2. The expression of Etsl, c-Jun, Stat3, MMP1 and HER2 were significantly increased in IDC and the expression of MMP1, HER2 and VEGF were all closely correlated with Etsl and Stat3, which implied that transcription factors Etsl and Stat3 may up-regulated the expression of proangiogenic factors MMP1, HER2 and VEGF. Etsl and Stat3 might be the key point in regulating angiogenesis ofbreast cancer.3. The correlation between these factors and MVD in IDC group implied that these factors play an important role in promoting angiogenesis in breast cancer. No correlations were found among groups of IPL, which implied that the effects of these factors were not significantly in IPL.4. Correlation between the expression of Etsl, Stat3, MMP1 and HER2 and clinical data implied that they could evaluate the prognosis of patient.5. As the important transcription factors in regulating angiogenesis in breast cancer, Etsl and Stat3 might become an important target of gene therapy ofanti-angiogenesis in breast cancer.