Byline: Xing-hua Li (1), Jun-wei Song (2), Jun-ling Liu (1,3), Shu Wu (1), Le-shi Wang (4), Li-yun Gong (2), Xi Lin (1,5) Keywords: Breast cancer; SRPK1; Prognosis; Immunohistochemistry Abstract: Breast cancer is the most common cancer and the second leading cause of mortality for women worldwide. It is necessary to identify valuable molecular markers to predict breast cancer progression in patients and treatment effect. Serine--arginine protein kinase 1 (SRPK1), a member of SR kinase family, phosphorylates the SR splicing factors which plays essential roles in normal cell development and multiple human diseases. In the current study, we wanted to explore if there are any relationships between SRPK1 expression in breast cancer and its clinical characteristics. The results showed that SRPK1 is upregulated in breast cancer cell lines and tissues at both mRNA and protein levels, measured by quantitative reverse transcriptase PCR and Western blotting. Immunohistochemical analysis showed a high expression of SRPK1 in 132 paraffin samples of patients with breast cancer statistical analyses demonstrated that high expression of SRPK1 significantly correlated with clinical staging of patients with breast cancer (P Author Affiliation: (1) State Key Laboratory of Oncology in Southern China, Department of Experimental Research, Cancer Center, Sun Yat-sen University, 651 Dongfeng East Road, Guangzhou, 510060, Guangdong, People's Republic of China (2) Department of Biochemistry and Biology, School of Medicine, Shenzhen University, Ave 3688, Shenzhen, 518061, Guangdong, People's Republic of China (3) Medicine Oncology, Cancer Center, Sun Yat-sen University, 651 Dongfeng East Road, Guangzhou, 510060, Guangdong, People's Republic of China (4) Department of Stomatology, School of Medicine, Central South University, 87 Xiangya Road, Changsha, 410000, Hunan Province, People's Republic of China (5) Ultrasonic Department, Cancer Center, Sun Yat-sen University, 651 Dongfeng East Road, Guangzhou, 510060, Guangdong, People's Republic of China Article History: Registration Date: 13/06/2014 Received Date: 03/04/2014 Accepted Date: 13/06/2014 Online Date: 25/06/2014 Article note: Electronic supplementary material The online version of this article (doi: 10.1007/s12032-014-0083-8) contains supplementary material, which is available to authorized users.