A recent study from our laboratory utilizing this model system suggested that post-irradiation (IR) gene expression data from LCLs derived from blood of patients with sequence alterations in BRCA1 and BRCA2, and from familial breast cancer patients without such alterations (BRCAX) has potential to predict BRCA1, BRCA2 and BRCAX mutation status with up to 62% accuracy [9]. The gene discussed is BRCA1; the disease is hereditary breast carcinoma.