Localisation of phospho-ribosomal protein S6 kinase 1 expression in infiltrating breast cancer and the association with the clinicopathological characteristics and prognosis

Objective To assess the relation of the localisation of phospho-ribosomal protein S6 kinase 1 (p-S6K1) expression with clinicopathological characteristics,as well as prognosis in infiltrating breast cancer.Methods The expression of p-S6K1 in different subcellular sites was evaluated in 185 samples of infiltrating breast cancer tissues.The relationship between the expression of different sites and the clinicopathologic variables was analyzed,as well as the prognosis of breast cancer.Results The positive expression rate of cytoplasmic p-S6K1 was 48.1％ in tumors and 20.0％ in the adjacent tissues,respectively (P ＜0.05).The expression of cytoplasmic p-S6K1 was significantly associated with lymph node metastasis (P ＜ 0.05),whereas its nuclear expression was correlated with clinical stage (P ＜ 0.05).The disease-free survival of tumors with p-S6K1 positively expressed in cytoplasm was significantly shorter than that of the tumors with negative expression (P ＜ 0.05).Clinical stage,lymph node metastasis and cytoplasmic expression of p-S6K1 were independent prognostic factors (P ＜ 0.05).Conclusion Cytoplasmic p-S6K1 expressions can be considered as indicators of different clinicopathological characteristics of tumors and may act as an independent prognostic factor of infiltrating breast cancer. Key words: Infiltrating breast carcinoma;  Phospho-ribosomal protein S6 kinase 1 ;  Cytoplasmice;  Prognosis