Immunohistochemical cell proliferation analyses have come into wide use for evaluation of tumor malignancy. Topoisomerase II alpha (topo II alpha), an essential nuclear enzyme, has been known to have cell cycle coupled expression. We here show the usefulness of quantitative analysis of topo II alpha mRNA to rapidly evaluate cell proliferation in brain tumors. A protocol to quantify topo II alpha mRNA was developed with a real-time RT-PCR. It took only 3 h to quantify from a specimen. A total of 28 brain tumors were analyzed, and the level of topo II alpha mRNA was significantly correlated with its immuno-staining index (p < 0.0001, r = 0.9077). Furthermore, it sharply detected that topo II alpha mRNA decreased in growth-inhibited glioma cell. These results support that topo II alpha mRNA may be a good and rapid indicator to evaluate cell proliferate potential in brain tumors. (c) 2005 Elsevier Inc. All rights reserved.