Chromosome evolution and high-resolution analysis of leucocytes, bone marrow, and tumor cells of retinoblastoma patients.
High-resolution cytogenetics were applied to leucocytes, bone marrow, and tumors of 8 retinoblastoma (Rb) patients in search of microdeletions or subtle rearrangements and in order to determine clonal evolution. Four of 9 tumors (Rb1, Rb6.1, Rb6.2, and Rb8) showed a deletion in the characteristic region on 13q while 2 others (Rb3 and Rb4) were hemizygous for chromosome 13 in approximately one-third of the cells. Our study presents a particularly high incidence of chromosome 13 anomalies as compared to the previously published data. Furthermore, comparison of karyotypes of 3 significant cases (Rb1, Rb6, and Rb8) allows the reconstruction of the necessary steps in the evolution of retinoblastoma. It also shows the need for a double mutation in tumor development, both in hereditary and non-hereditary cases. High-resolution chromosome analysis of retinoblastoma patients provides a rare opportunity to study the succession of events necessary for tumor development.
Lemieux
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Département d'Anatomie, Faculté de Médecine, Université de Montréal, Québec, Canada.
Richer
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D001853:Bone Marrow / Q000648:ultrastructure*; D002675:Child, Preschool; D002871:Chromosome Banding; D002872:Chromosome Deletion; D002882:Chromosomes, Human, Pair 13; D005134:Eye Neoplasms / Q000235:genetics* / Q000648:ultrastructure; D015321:Gene Rearrangement; D006801:Humans; D007223:Infant; D007621:Karyotyping; D007962:Leukocytes / Q000648:ultrastructure*; D012175:Retinoblastoma / Q000235:genetics* / Q000648:ultrastructure