Koyama K, Kagamu H, Miura S, et al. Reciprocal CD4+ T -cell balance of effector CD62Llow CD4+ and CD62LhighCD25+ CD4+ regulatory T cells in small cell lung cancer reflects dise ase stage. Clin Cancer Res 2008;14:6770-9. 73. Alexandrov LB, Nik- Zainal S, Wedge DC, et al. Signatures of mutational processes in human cancer. Nature 2013;500:415-21. 74. George J, Lim JS, Jang SJ, et al. Comprehensive genomic profiles of small cell lung cancer. Nature 2015;524:47-53.