The role of p-STAT3 (ser727) revealed by its association with Ki-67 in cervical intraepithelial neoplasia

Abstract

Objectives. Constitutive activation of signal transducer and activator of transcription 3 (STAT3) has been described in many types of cancers. However, the role of phospho-STAT3 (p-STAT3) at serine residue 727 is in large part undetermined. Our purposes of this study were to evaluate the expression patterns of p-STAT3 (ser727) in cervical intraepithelial neoplasia (CIN) and to explore its possible role in the progression of cervical cancer. Methods. Paraffin-embedded sections from 56 patients including 20 CIN 1, 10 CIN 2, and 26 CIN 3 were collected in this study. Immunohistochemical analysis was performed, and the expression patterns of p-STAT3 (ser727) were categorized by semiquantitative method and further correlated with the CIN histopathologic grade using the χ 2 test with Bonferroni adjustment for multiple comparisons and with the proliferation marker Ki-67 expression using Fisher's Exact Test. Results. The categorized high p-STAT3 (ser727) expression group in nuclei of dysplastic cells was significantly higher in CIN 3 (76.92%), in comparison with CIN 1/2 (13.33%, P < 0.001). Moreover, both the nuclear and cytoplasmic p-STAT3 (ser727) expressions were correlated with Ki-67 nuclear staining ( P < 0.001 and < 0.001, respectively). Conclusions. Our result revealed that aberrant expression levels of p-STAT3 (ser727) were significantly correlated with CIN lesion grade and cell proliferation. Evaluation of p-STAT3 (ser727) expression may provide additional prognostic information for the clinical course of the disease and therefore to be developed as a prognostic indicator for cervical cancer.