Abstract
Immunohistochemical methods are widely used for estimating growth potential and malignancy of brain tumors. Bromodeoxyuridine labeling index (LI) is the most classical one. MIB-1 immunohistochemistry is now the most popular method. An antibody against topoisomerase II-alpha also has become familiar. Cell proliferation kinetics was determined not only by growth fraction but also by cell cycle time and cell loss. Immunohistochemical methods measure a parameter related to the growth fraction. In untreated tumors, they are of value to predict the growth speed since the mean cell cycle time in individual tumor cells and cell loss rate may be relatively constant, or may change tightly coupling with growth fraction. However, when a tumor is treated with irradiation or chemotherapy, cell loss may become prominent and cell cycle time prolongs. In this situation, immunohistochemical methods are no longer reliable. The degree of over-estimation varies among the proliferation markers depending on the phase of cell cycle arrest or prolongation.
