Downregulation of PCDH9 predicts prognosis for patients with glioma.

Recent evidence has indicated that biological markers are essential in estimating the prognosis of patients with gliomas. The aim of this study was to determine the status and clinical significance of a novel tumor suppressor, PCDH9 (protocadherin 9) in glioma using tissue microarrays and immunohistochemistry. Normal brain tissue showed strong positive immunostaining for PCDH9, but this was downregulated in the primary cerebral glial tumor samples (51.7%). Loss of PCDH9 expression was associated significantly with a higher histological grade. Survival analysis demonstrated that patients with PCDH9-negative tumors had significantly shorter survival times than those with PCDH9-positive tumors and that PCDH9 was an independent prognostic factor. Our results suggest that PCDH9 might function as a tumor suppressor during cancer development and progression and could be regarded as a useful biomarker for predicting the outcome of patients with cerebral glial tumors.