Fig. 2

Histone γ-H2AX foci in PBMCs derived from control donors and normally-reacting and radiosensitive (grade 2–3) RC patients. a DNA damage assessed by means of the histone γ-H2AX assay in non-irradiated and b-d irradiated PBMCs derived from normally-reacting RC patients (grade 0 and 1, up triangles) and radiation-sensitive (grade 2 and 3, down triangles) cancer patients compared to cells from apparently healthy donors (circles). Initial (b, 0.5 Gy, 30 min post-IR), residual DNA damage 24 h after in vitro 2 Gy (c) or 72 h after 5 clinical radiation fractions (d) were assessed in PBMCs after irradiation either in vitro (b, c) or in vivo (d). Filled squares represent the mean values (± SE) for the respective group. “n.s.” indicates that the difference was not highly significant (p > 0.05). “n.d.” means not determined. Clinical GI toxicity to RT was controlled at the end of RT (see Additional file 1: Table S2) and used as an indicator for clinical radiosensitivity according to the RTOG score [27]