Consistent with previous results in human SCLC specimens (Fig. 5B), TREX1 expression was higher in the PDX sample derived from a posttreatment tumor, at protein and mRNA levels (Fig. 5C; Supplementary Fig. S5A), which further suggests that TREX1 is induced after chemotherapy treatment in human SCLC. The gene discussed is TREX1; the disease is neoplasm.