It has been suggested that chromosome instability is a constitutional factor which may be characteristic of families with an increased risk for the development of malignancies. In this study spontaneous chromosome aberrations, sister chromatid exchanges (SCEs) and chromosome sensitivity to bleomycin were analysed in cultured lymphocytes from 13 families with sporadic non-hereditary unilateral retinoblastoma patients. The significantly increased chromosome instability was detected only by the bleomycin test. Higher mean values of breaks/cell were found in all groups of relatives: patients, parents and siblings.
S. Zajaczek, Department of Genetics and Pathomorphology-Hereditary Cancer Centre, Pomeranian Medical University, Al. Powstancow Wlkp. 72, 70-111 Szczecin, Poland