Additional file 1: Fig. S1. Human caspase-4 co-immunoprecipitated with k-RAS in human tumor samples. Human digested lung tumor samples were analyzed by means of Native-PAGE. The isotype control of the antibody against caspase-4 did not show any aspecific band. Similarly eluted samples did not show any positive band, implying that caspase-4 and K-RAS are bound in human lung tumor samples obtained by NSCLC patients. Experiments were performed three times.