Additionally, to validate the relationship of the FOXM1/RRM2 axis in SCLC cells, we performed genetic perturbation of FOXM1 using small interfering RNA (siRNA)-mediated knockdown in SBC5 cells and found that knockdown of FOXM1 decreased the expression of RRM2 (supplementary Fig. S17B). The gene discussed is RRM2; the disease is small cell lung carcinoma.