DNA Ploidy, Bromodeoxyuridine labelling index, S-phase fraction and AgNOR counts in brain tumours

Abstract

DNA ploidy and the proliferative potential in 88 brain tumours were investigated using the bromodeoxyuridine labelling index (BrdUrd LI), S-phase fraction (SPF) and an argyrophilic nucleolar organizer regions (AgNOR) technique. The study included 65 highly malignant (AIII–AIV), and 23 low-grade (AI–AII) gliomas. One fragment of the tumour was fixed in Carnoy's solution for AgNOR test, while the other fragments were used for flow cytometric determination of the labelling index, SPF and DNA ploidy. For the BrdUrdLl, tumour samples from each patient were incubated in vitro for one hour at 37°C with BrdUrd using a high pressure oxygen method. After fixation and staining, the percentages of BrdUrd-labelied cells (BrdUrdLI) and unlabelled S-phase cells (SPF) were evaluated. The tumours showed variability in the BrdUrdLI values, SPF and AgNOR counts/cell nucleus. However, grade dependent differences in the proliferating rate were only found to exist on the basis of BrdUrdLI and AgNOR counts. The same percentage of DNA aneuploidy (56 %) was found in high-grade as well as in low-grade gliomas. A linear – regression analysis showed a significant correlation between the results of three applied methods: BrdUrdLl, SPF and AgNOR counts.