Signal transducer and activator of transcription 1 in breast cancer: Analysis with tissue microarray

Background: Constitutively activated signal transducer and activator of transcription (STAT) proteins are found in various types of tumors. However, there is still very limited information about the role of STATs in breast cancer. The power of the tissue microarray analysis (TAM) technique is the capability of performing a series of analyses of thousands of specimens in a parallel fashion with minimal damage to the original blocks. This study was designed to use TAM in determing the STAT1 status in breast cancer tissues. Materials and Methods: Archival tissue specimens from 102 patients with primary invasive breast cancer were selected and STAT1 expression was analyzed using immunohistochemical staining with tissue microarray. The data of primary tumor staging, age, estrogen receptor status, lymph node status, histological grading and TNM staging were also collected. Results: There were 18 patients (17.6%) with 0 expression in STAT1, 29 patients (28.4%) with I expression in STAT1, 21 patients (20.6%) with 2 expression in STAT1 and 34 patients (33.4%) with 3 expression in STAT1. There was no significant relationship between STAT1 expression and age (p=0.203), estrogen receptor status (p=0.221), histological grading (p=0.861), primary tumor staging (p=0.918), lymph node status (p=0.53), or TNM staging (p=0.826). There was no survival difference noted among the four groups with different STAT1 expression (p=0.859). Conclusion: Immuno-histochemical staining with tissue microarray analysis was convenient and feasible for the analysis of STAT1 expression status in breast cancer. STAT1 expression did not show significant correlation with the overall survival rate.