We first exposed the lung adenocarcinoma NCI-H838RBM14/NCI-H838luc and NCI-H1650RBM14/NCI-H1650luc cell line pairs to 2 Gy ionizing radiation (IR), and by immunofluorescence measured levels of nuclear γ-H2AX foci as a biomarker of DNA damage. The gene discussed is H2AX; the disease is lung adenocarcinoma.