PROLIFERATING CELL NUCLEAR ANTIGEN IN THE DETERMINATION OF GROWTH-RATES IN ACOUSTIC NEUROMAS

The growth rate of acoustic neuromas is difficult to predict clinicall y; however, the ability to do so would be of benefit to the clinician for patient prognostication. Laboratory studies utilizing flow cytomet ry and immunologic methods have been used to investigate growth rates of acoustic neuromas. The purpose of this pilot immunohistochemical st udy, using proliferating cell nuclear antigen (PCNA) on 22 randomly se lected vestibular schwannomas, was to compare the growth factors, dete rmined immunohistochemically, with the growth rate in this class of le sions. Proliferating cell nuclear antigen is an antibody against DNA p olymerase delta, which is expressed in late G1 through S phase of the cell cycle. The advantage of using PCNA is that standard archival form alin-fixed, paraffin-embedded tissues may be analyzed and that PCNA de tects cells in G1 through S phase, allowing relative comparison to stu dies utilizing S-phase fractions, determined by flow cytometry. Result s indicate that PCNA immuno-histochemical analysis may potentially off er prognostic information relating to the growth potential of each tum or for individual patients with vestibular schwannomas. Further study with an expanded patient population is planned to explore this potenti al.