Fig. 1

Three-color fluorescence in situ hybridization to determine radiosensitivity. Metaphase spreads of human blood lymphocytes, stained with chromosome specific probes for chromosome # 1 (red, rhodamine), chromosome # 2 (green, FITC) and chromosome # 4 (yellow, rhodamine + FITC). DNA was stained with DAPI (blue) (a-d). Normal metaphase spread (a). Metaphase spread with two translocations of # 2 with a blue chromosome and # 4 with a blue chromosome and an insertion of # 1 into a blue chromosome. The three aberrations were scored as 7 breaks (b). Metaphase spread with a dicentric chromosome of # 1 and # 2, a translocation of # 1 and # 4 and an insertion of # 1, # 2 and # 4. The aberrations were scored as 5 breaks (c). Metaphase spread with complex chromosomal rearrangements (CCR). The aberrations were scored as 12 breaks (d). Gender distribution of 202 healthy individuals in different age groups (9–27, 28–41, 42–55, 56–69 and 70–81 years) and of 393 patients with various cancer diseases (17–40, 41–52, 53–64, 65–78, 79–91 years) (e). Number of healthy individuals and cancer patients classified into divisions of 0.02 breaks per metaphase. Zero point five B/M (dashed line) and 0.6 B/M (solid line) are marked as a cutoff point to increased and distinctly increased radiosensitivity. B/M background without irradiation (f) and after irradiation of 2 Gy, corrected by the background (g). The data were fitted using a Gaussian distribution; scale 10 μm