An in vitro investigation of genetic susceptibility to cancer in diploid fibroblasts from retinoblastoma patients.
Thirty-two diploid fibroblast strains from individuals with the three forms of retinoblastoma were examined with an in vitro clonogenic survival assay to determine their sensitivity to killing by X rays. Strains from sporadic unilateral retinoblastoma patients and normal controls were indistinguishable from one another (group D0's = 147 +/- 15 rads and 146 +/- 5 rads, respectively) while the strains from patients with the hereditary form of the disease were significantly more X-ray sensitive (D0 = 111 +/- 12). Strains derived from individuals with the D-deletion form of the disease resembled the hereditary strains with respect to sensitivity and heterogeneity, suggesting a possible, common etiology for these two forms of the disease. A DNA-repair defect is hypothesized as reflected by the observed hypersensitivity to X-irradiation in these cells. We suggest that this defect may be associated with the enhanced frequency of spontaneous and radiation-induced second tumors seen in some retinoblastoma patients.
D002875:Chromosomes / Q000528:radiation effects; D004171:Diploidy; D005134:Eye Neoplasms / Q000235:genetics*; D005347:Fibroblasts / Q000528:radiation effects; D006801:Humans; D007621:Karyotyping; D012175:Retinoblastoma / Q000235:genetics*; D014965:X-Rays