Expression of PHLPP2 correlates with clinicopathologic characteristics and prognosis in colorectal cancer.

ABSTRACT

PH domain leucine-rich repeat protein phosphatase 2 (PHLPP2) belongs to the phosphokinase family, that has been reported to play an important role in several cancers. However, the expression of PHLPP2 and its correlation with clinicopathologic characteristics in colorectal cancer (CRC) have yet to be determined. The aim of this study is to investigate the expression of PHLPP2 and explore its role in CRC. The expression of PHLPP2, PTEN, PI3KCA, and PI3KCB in 130 cases of CRC and normal tissues was assessed by immunohistochemistry. In addition, the expression of PHLPP2, PTEN, PI3KCA, and PI3KCB in 32 pairs of CRC tissues and their corresponding normal tissues was determined by RT-PCR and western blotting, respectively. PHLPP2 expression in CRC was significantly lower than that of normal tissues. However, PHLPP2 mRNA shows no significant difference between CRC and normal tissue. PTEN expression in left colorectal cancer (LCC) was absent, while PI3KCA and PI3KCB in right colorectal cancer (RCC) were significantly higher than those in LCC. PHLPP2 was negatively correlated with p-Akt1 in CRC. The expression of p-Akt1 in PHLPP2 (+)/PTEN (+) in CRC tissues was significantly lower than that in other groups. PHLPP2 expression was correlated with differentiation, invasion, and lymph node metastasis. Kaplan-Meier analysis and multivariate analysis reveal that PHLPP2 is closely related to prognosis; more importantly, it is an independent prognostic factor for CRC. In conclusion, PHLPP2 may play a major role in the development, metastasis, and prognosis of CRC.