ODC mRNA as a prognostic factor for predicting recurrence in meningiomas

In proliferating neoplastic cells, activity of the enzyme ornithine decarbo xylase (ODC) increases. Among other brain tumors, ODC activation could also be observed in meningiomas. In the present study, we have investigated ODC gene expression in primary and recurrent meningiomas at the transcriptiona l level. ODC mRNA (messenger ribonucleic acid), ODC activity, number of mitoses, and Ki-67 index as a marker for nuclear proliferation were quantified in three different groups of meningiomas: tumors without recurrence in a 8.4 years median follow-up period, tumors with recurrence within a median follow-up o f 3.0 years, and their corresponding recurrent tumors. ODC mRNA level was significantly higher in meningiomas with later recurrenc e as compared to meningiomas without recurrence (p less than or equal to 0. 01), whereas it declined in the recurrences of the second group (p less tha n or equal to 0.001). In contrast, ODC activity showed no difference betwee n the two groups of primary tumors, but a significant increase of enzyme ac tivity could be observed in the recurrences as compared to the correponding primary tumors (p less than or equal to 0.001). Likewise, an increase of t he Ki-67 index could be detected in the recurrent group (p less than or equ al to 0.001). These results suggest that ODC mRNA may represent a prognosti c factor for predicting recurrence in meningiomas.