[Increased sister-chromatid exchanges in fibroblasts from a del(13)-retinoblastoma patient (author's transl)]

Sister-chromatid exchanges were studied in fibroblasts from a child with del(13)-retinoblastoma. The skin biopsy was performed before the clinical onset of the tumor. The observed frequency of SCE, 19.65 per cell, was significantly increased as compared to that of a normal control, 14.68 per cell (t = 3.57, p < 0.001).