PREDICTION OF HUMAN CELL RADIOSENSITIVITY - COMPARISON OF CLONOGENIC-ASSAY WITH CHROMOSOME-ABERRATIONS SCORED USING PREMATURE CHROMOSOME CONDENSATION WITH FLUORESCENCE IN-SITU HYBRIDIZATION

Purpose: The purpose of the present investigation was to determine whe ther chromosome aberrations scored by premature chromosome condensatio n (PCC) and fluorescence in situ hybridization (FISH) can predict the radiosensitivity of human cell lines, thereby providing a possible mea ns of assessing the in situ radiosensitivity of normal tissues and the radiocurability of individual human cancers. Methods and Materials: W e used four cells lines of different radiosensitivity: normal human fi broblasts (AG1522), ataxia-telangiectasia fibroblasts (AT2052), a huma n fibrosarcoma cell line (HT1080), and a human melanoma cell line (mel anoma 903). These were irradiated in plateau phase with a range of dos es and assessed both for clonogenic cell survival and for aberrations in a single chromosome (number 4) immediately after, and 24 h after ir radiation. Results: The initial number of breaks in chromosome 4 was p roportional to irradiation dose and was identical for all the differen t human cell lines, irrespective of radiosensitivity. On the other han d, the number of chromosome 4 breaks remaining 24 h after irradiation reflected the radiosensitivity of the cells such that the relationship between residual chromosome aberrations and cell survival was the sam e for the different cell lines. Conclusions: These results suggest tha t the scoring of chromosome aberrations in interphase using FISH with PCC holds considerable promise for predicting the radiosensitivity of normal and tumor tissues in situ.