Prognostic significance of nuclear DJ-1 expression in astrocytoma

The present study was conducted to determine whether any correlation exists between the expression of DJ-1 and WHO grading of the tumor or patient prognosis, and to analyze the function of this oncogene in astrocytomas. Twenty-nine formalin-fixed and paraffin-embedded glioblastomas (grade IV), 21 anaplastic astorocytomas (grade III), and 14 diffuse astrocytomas (grade II) were immunohistochemically studied to identify the expression of DJ-1 protein. The expression of DJ-1 was detected both in the nucleus and cytoplasm of tumor cells; however, such expression varied from case to case. While there was no difference in the cytoplasmic expression of DJ-1 among astrocytomas, its nuclear expression was inversely correlated with the WHO grading of astrocytomas. Moreover, the overall survival of patients with maintained (group 1) or mixed (groups 2 and 3) was significantly longer than those with decreased (group 3) expression (p=0.0063). The present study demonstrated that the survival of patients with astrocytomas was correlated with the nuclear DJ-1 status of the tumor. We herein demonstrated for the first time that the DJ-1 molecule might therefore play an important role as a tumor suppressor in astrocytomas.