Toxicity from radiation therapy associated with abnormal transcriptional responses to DNA damage

Peripheral blood lymphocytes from a total of 57 patients were immortalized with Epstein-Barr virus. Fourteen radiation-therapy patients suffered unusual levels of radiation toxicity (RadS). Thirteen radiation-therapy patients with limited toxicity (RadC) were enrolled as controls. Fifteen patients diagnosed with skin cancer before age 40 (SkCa) were used as a second group of controls. Fifteen healthy subjects without any history of cancer (NoCa) were matched to the skin cancer patients and used as a third group of controls. Cells were exposed to mock treatment (Mock), ultra-violet radiation (UV), or ionizing radiation (IR). For UV radiation treatment, cells were exposed to 10 J/m^2 and harvested for RNA 24 hours later. For IR treatment, cells were exposed to 5 Gy of IR and harvested for RNA 4 hours later. For example, RadS1-Mock refers to cells from radiation sensitive patient 1 exposed to mock treatment. The published manuscript (PNAS 101:6634, 2004) can be found at http://www.pnas.org/cgi/doi/10.1073/pnas.0307761101 Data were analyzed with Affymetrix MAS version 4.0. Normalization – A reference data set was generated by averaging the expression of each gene over all data sets. The data for each hybridization were compared with the reference data set in a cube root scatter plot. A linear least-squares fit to the cube root scatter plot was then used to normalize each hybridization. Keywords = Gene expression in lymphoid cells of cancer patients Keywords: repeat sample