272 Preliminary results of a prospective evaluation of 3H-thymidine labeling index in gliomas

Abstract

The aim of the present study is to evaluate the biological meaning and the potential clinical usefulness of cell proliferation evaluation in gliomas, based on 3 H-thyrnidine labeling index (TLI) which provided powerful prognostic indications in several other malignancies. Twenty-nine patients with untreated primary gliomas have been to date enrolled, Fresh tissue samples were incubated with 3 H-thyrnidine for one hour. The fragments were then washed and fixed in paraffin. Five-micron sections were processed by autoradiography and stained with hematoxylin and eosin. TLI was expressed as the ratio between the labeled cells and the total number of tumor cells counted (at least 3000). Five cases were not evaluable due to massive tumor necrosis. In the other 24, the TLI ranged between 0.1% and 33.3%, with a median value of 4,8%; interquartile range was between 3.5% and 11%. TLI values did not show a significant association with the site or size of tumor but had a trend with hysto logical grade. In the few cases in which the follow-up has been already long enough, higher TLI values occurred in patients with shorter survival. These are preliminary findings until a number of events adequate for a statistical analysis is reached. The following preliminary conclusions can be drawn: (1) TLI is feasible in a high percentage of gliomas; (2) the wide range of TLI values found in the present series indicate that it may be used to select patient groups with different biological and/or clinical characteristics. Supported by AIRC (Associazione Italiana Ricerca sul Cancro).