**Figure 1**. **Isocitrate-dependent NADPH production and alpha-ketoglutarate-dependent NADPH consumption of wild-type or R172 mutant IDH2**. Number of mice: (**A**) A549 tumors: n=14 (vehicle), n=13 (cimetidine), n=4 (doxorubicin) (**B**) ACHN tumors: n=15 (vehicle), n=15 (cimetidine). Two-tailed Welch’s *t*-test on Day 11 relative volumes between vehicle or doxorubicin treated A549 tumors; *t* (6.73) = 2.68, uncorrect *p* = .0325 with *a priori* alpha level = .0167; (Bonferroni corrected *p* = .0976). Two-way ANOVA interaction between cell line (A549 or ACHN) and treatment (vehicle or cimetidine) on natural log transformed Day 11 relative volumes; *F* (1,53) = 3.88, *p* = .054. Pairwise contrast between A549 tumors treated with vehicle or cimetidine; *t* (53) = 2.16, uncorrected *p* = .035 with *a priori* alpha level = .0167; (Bonferroni corrected *p* = .105). Pairwise contrast between ACHN tumors treated with vehicle or cimetidine; *t* (53) = -0.58, uncorrected *p* = .562 with *a priori* alpha level = .0167; (Bonferroni corrected *p* > .99). Access [analysis script][1] for the statistical tests related to this figure. This script will call the [data][2] directly from the OSF. <br> [1]: https://osf.io/updga/ [2]: https://osf.io/xxjje/