AN ASSOCIATION OF THE RB GENE WITH OSTEOSARCOMA - MOLECULAR-GENETIC EVALUATION OF A CASE OF HEREDITARY RETINOBLASTOMA

A 24-year-old male patient with hereditary retinoblastoma and a poorly differentiated osteoblastic osteogenic sarcoma was found to carry a m utant RB1 allele in all cells. This findings was most likely a point m utation or microdeletion because Southern blot analysis of peripheral blood DNA failed to disclose any structural aberration of the RB1 gene . A somatic mutation (deletion) affecting the other allele was found i n the osteosarcoma cells. Management of tumor by external radio-therap y in early age is questioned because the effect of irradiation is to s ignificantly increase the total incidence of second tumors above the a lready high incidence in non-irradiated patients.