Prognostic significance of phosphorylated STAT-1 expression in premenopausal and postmenopausal patients with invasive breast cancer.

Aims:   STAT-1 is the first member of the family of signal transducers and activators of transcription (STATs). In breast cancer experimental models, an apoptotic and antiproliferative effect has been demonstrated. Our aim was to study the role of phosphorylated STAT-1 (pSTAT-1) in invasive breast carcinoma and its prognostic significance in premenopausal and postmenopausal patients.

Methods And Results:   Immunohistochemistry was performed in 165 patients in order to detect the expression of pSTAT-1 and its correlation with oestrogen receptor (ER), progesterone receptor (PR), caspase-3, and pAkt. pSTAT-1 was immunodetected in the cytoplasm of the malignant cells (11.6%). In premenopausal patients, cytoplasmic pSTAT-1 was positively correlated with stage (P = 0.014), ER (P = 0.008), caspase-3 (P = 0.029), and pAkt (P = 0.045). Univariate analysis showed that cytoplasmic pSTAT-1 was associated with poor overall survival (P = 0.042) and the phenotype of pSTAT-1/ER or PR coexpression with shorter disease-free survival (P = 0.012). In contrast, in postmenopausal patients, no association with clinicopathological parameters and survival was observed, except for the relationship of pSTAT-1/ER or PR coexpression with longer disease-free survival (P = 0.034).

Conclusions:   This is the first study examining the role of pSTAT-1 in premenopausal and postmenopausal women with invasive breast cancer. Our results suggest that pSTAT-1 is related to tumour progression in premenopausal patients through the advanced stage and worse survival.