Diagnostic value of PRND gene expression profiles in astrocytomas: Relationship to tumor grades of malignancy

Doppel (PRND) is a paralogue of the mammalian prion (PRNP) gene. It is abundant in testis and, unlike PRNP, it is expressed at low levels in the adult central nervous system (CNS). Besides, doppel overexpression correlates with some prion-disease pathological features, such as ataxia and death of cerebellar neurons. Recently, ectopic expression of doppel was found in two different tumor types, specifically in glial and haematological cancers. In order to address clinical important issues, PRND mRNA expression was investigated in a panel of 111 astrocytoma tissue samples, histologically classified according to the World Health Organization (WHO) criteria (6 grade I pilocytic astrocytomas, 15 grade II low-grade astrocytomas, 26 grade III anaplastic astrocytomas and 64 grade IV glioblastoma multiforme). Real-time PRND gene expression profiling, after normalisation with GAPDH, revealed large differences between low (WHO I and II) and high grade (III and IV) of malignancy (P<0.001). Extensive differences in PRND gene expression were also found within each grade of malignancy, suggesting that PRND mRNA quantitation might be useful to distinguish astrocytoma subtypes, and important in disease stratification and in the assessment of specific treatment strategies.