DETERMINATION OF RADIOSENSITIVITY IN ESTABLISHED AND PRIMARY SQUAMOUS-CELL CARCINOMA CULTURES USING THE MICRONUCLEUS ASSAY

In this study, the cytokinesis-block micronucleus assay (CBMN) was use d to measure radiosensitivity in three established cell lines (SCC-61, V175 and V134) and 10 primary cell cultures of squamous cell, carcino ma (SCC) of the head and neck. Assessment involved optimisation of the assay to determine cytochalasin-B (CB) concentration and sampling tim e postirradiation. A much closer correlation between dose-response dat a measured in the clonogenic and micronucleus assays was found when th e micronucleus assay was performed under standardised conditions for e ach cell line (2 mu g/ml CB: 48 h postirradiation) instead of predeter mined optimised assay conditions. This indicates that, for these SCC c ell lines, the CBMN assay may be able to predict in vitro radiosensiti vity. To be of clinical use in predicting radiosensitivity, the CBMN a ssay also needs to be evaluated with primary cell cultures. In this st udy, no relationship between micronucleus frequency at 2 or 6 Gy and p atient clinical outcome 12 months following surgery and radiotherapy w as seen. Similarly, no association between patient outcome and tumour stage, nodal stage and histology was observed. These CBMN assay data f rom the primary cell cultures are presently inconclusive as a measure of patient tumour radiosensitivity. (C) 1997 Published by Elsevier Sci ence Ltd.