Molecular genetic analysis as a tool for evaluating stereotactic biopsies of glioma specimens

Over the last years, distinct genetic lesions have been associated with ind ividual tumor entities. Stereotactic biopsy has become an essential diagnos tic tool in surgical neuro-oncology. In order to evaluate the potential of molecular analyses in stereotactic biopsies, we examined a series of 156 hu man brain tumors from patients undergoing stereotactic biopsy for molecular alterations typically seen in astrocytic gliomas and compared those result s with a control group of 268 astrocytic tumors obtained at open surgery. S tereotactic biopsies of astrocytomas with borderline histopathological feat ures between the WHO grades II and III showed a higher rate of allelic loss es on chromosome 10 than these of the WHO grade II from open surgery (p = 0 .011). Stereotactic biopsies of astrocytomas with borderline histopathologi cal, features between the WHO grades III and IV showed a higher rate of all elic losses on chromosome IO than those of the WHO grade III from open surg ery (p = 0.013). This indicates that stereotactic biopsies with features in termediate between grades are likely to correspond to the higher malignancy grade. Our data demonstrate that molecular genetic approaches can be succe ssfully applied to stereotactic glioma biopsies. The difference in the dist ribution of malignancy associated genetic alterations between a stereotacti c and openly resected group of gliomas indicates that histopathology may un derestimate the malignant potential in some stereotactic specimens. We prop ose to further evaluate the molecular analysis of stereotactic glioma biops ies as a useful adjunct to standard histopathological procedures.