Gene set enrichment analysis of basal and in vitro irradiation differentiates breast cancer patients with late skin radiotherapy toxicity

Radiation-induced late effects remain a common cause of morbidity amongst cancer survivors. The purpose of this study was to investigate the molecular basis underlying the radiotherapy-induced late skin toxicity in breast cancer patients who were previously assessed for radiation-induced lymphocyte apoptosis (RILA). Peripheral blood mononuclear blood cells of 10 patients with severe skin late complications from radiotherapy and 10 patients without symptoms were mock-irradiated or irradiated with 8-Gy X-rays. The 48-h radiation response was analysed by gene expression profiling with Affymetrix microarrays Human Exon 1.0 ST array.Gene set enrichment analysis was performed to identify differentially expressed biological processes.