Expression of cyclin kinase subunit 2 in human breast cancer and its prognostic significance.

Cyclin kinase subunit 2 (CKS2) protein is a small cyclin-dependent kinase-interacting protein, which is essential for the first metaphase/anaphase transition of mammalian meiosis. CKS2 is up-regulated in various malignancies, suggesting that CKS2 maybe an oncogene. However, data on its expression pattern and clinical relevance in breast cancer are unknown. The aim of this study is to investigate CKS2 expression and its prognostic significance in breast cancer. The CKS2 expression was examined at mRNA and protein levels by real-time quantitative polymerase chain reaction (RT-PCR) and Western blotting analysis in paired breast cancer tissues and the adjacent normal tissues. The expression of CKS2 protein in 126 specimens of breast cancer was determined by immunohistochemistry assay. The relations between CKS2 expression and clinicopathological features were analyzed. The result show the expression of CKS2 mRNA and protein was higher in breast cancer than the adjacent normal tissues. Compared with adjacent normal breast tissues, Overexpression of CKS2 was detected in 56.3% (71/126) patients. Overexpression of CKS2 was significantly associated with large tumor size (P = 0.035), poor cellular differentiation (P = 0.016), lack expression of progesterone receptor (P = 0.006), and decreased overall survival (P = 0.001). In multivariate analysis, CKS2 expression was an independent prognostic factor for overall survival (Hazard ratio [HR] = 3.404, 95% confidence interval [CI] 1.482-7.818; P = 0.004). CKS2 is up-regulated in breast cancer and associated with large tumor size, lack expression of progesterone receptor, poor tumor differentiation and survival. CKS2 may serve as a good prognostic indicator for patients with breast cancer.