[Chromosome disorders in retinoblastoma cells].

The karyotype of 7 unilateral retinoblastomas was studied. Loss or a gain of chromosomes and structural chromosomal changes were observed in all tumors. Modal chromosome number was pseudodiploid in four and near-diploid in three tumors. There were no sex chromosomes (X or Y) in 3 tumors. Four tumors were characterized by the presence of an identical marker chromosome--i(6p). Two other markers--lp+ and 17q+ (probably, not quite identical)--were present in 4 and 3 tumors, respectively. The cells of two retinoblastomas contained both i (6p) and 17q+ markers.