Sister chromatid exchanges and chromosome aberrations in fibroblasts from patients with retinoblastoma.

The frequencies of sister chromatid exchanges (SCEs) and chromosome breaks were investigated in five diploid fibroblast strains derived from three patients with deletion 13 [del(13)] retinoblastoma, one patient with a hereditary form of retinoblastoma, and one trisomy 13. The fibroblasts with del(13)(q14q22) showed slightly increased SCEs (at a P level of 5-10%), but the others, including del(13)(q12q14), the hereditary form of retinoblastoma, and trisomy 13, did not have increased SCEs as compared to normal controls. No increase in chromosome breaks was found in these fibroblasts. The results suggest that retinoblastoma is not associated with spontaneous increased chromosomal instability.