To evaluate the sensitivity of the two culture systems to ferroptotic cell death, we treated the four lung cancer primary cultures (BBIRE-T248, PUC30, PUC36, and PUC37) with RSL3, a ferroptosis activator with selectivity for tumor cells bearing oncogenic Ras, which acts by inhibiting the glutathione peroxidase 4 (GPX4). The gene discussed is GPX4; the disease is neoplasm.