Immunoblot analysis of candidate proteins. MDA-MB-231 cells were exposed to the indicated single (A) or fractionated dose (B) of radiation. After 48 h, total protein was isolated and examined by western blot. (C) Band intensities corresponding to the indicated proteins were quantified by densitometry using ImageJ, normalized to the GAPDH loading control, and expressed as fold-change from each control. Values are mean ± SD for three independent experiments.