DNA-PLOIDY AND S-PHASE IN RECURRENT ASTROCYTOMAS - A RETROSPECTIVE STUDY BY FLOW-CYTOMETRY OF DEPARAFFINIZED SPECIMENS

Twenty-two patients with recurrent astrocytic tumors were treated surg ically two or even three times. At the time of the first surgery 6 tum ors were fibrillary astrocytomas (grade II), 9 anaplastic astrocytomas (grade III) and 7 glioblastomas (grade IV). Histopathological specime ns from second surgery demonstrated in 12 cases signs of higher grades of malignancy. Flow cytometry (FCM) did not reveal any significant ch anges of S-phase fraction (p = 0.55). This study supports the theory t hat, given enough time, the histopathology of brain tumors change sign ificantly from more benign forms to more malignant ones. The flow cyto metry (FCM) could trace a weak tendency to higher S-phase fractions at the time of the second surgery. No apparent change of ploidy pattern was observed. In spite of the unequivocal histopathological changes of the recurrent astrocytomas the flow cytometry failed to indicate simi lar changes in terms of ploidy and S-phase fraction parameters.