Study of the DNA content by flow cytometry and proliferation in 281 brain tumors

In this paper we investigate the distribution of DNA ploidy as well as proliferation rate (S phase of the cell cycle Ki-67 staining) in 281 tumors of the central and peripheral nervous system (87 meningiomas, 75 astrocytomas, 44 nerve sheath tumors, 25 brain metastases, 18 pituitary adenomas, 17 ependymomas, 12 oligodendrogliomas and 3 medulloblastomas) and their correlation with the histopathological grade. Considering all 281 tumors, aneuploidy is the most frequent finding present: 52%. This percentage increases with malignancy: 69% of malignant tumors are aneuploidy. Levels of aneuploidy decrease from brain metastases to pituitary adenoma (92% in brain metastases, 83% in oligodendrogliomas, 59% in nerve sheath tumors, 47% in ependymomas, 40% in astrocytomas, 35% in meningiomas and 33% in pituitary adenomas), but aneuploidy is also found in many benign tumors. With respect to proliferation rate of tumors, S phase above 20% were recorded in the more malignant tumors: brain metastases, oligodendrogliomas, high-grade ependymomas, high grade astrocytomas, and in atypical and malignant meningiomas, but this parameter is not able to distinguish between low and high grade tumors. However, Ki-67 reactivity was equivalent in all histologies with significant differences between low and high grade tumors.