IMPDH1 and cancer: To investigate whether IMPDH1 and/or IMPDH2 could be used as predictive biomarkers for drug response in patients with primary lung cancer (i.e., the primary cancer that accounts for ∼50% of BM15), we examined the correlation of IMPDH1 and IMPDH2 gene expression with drug sensitivity to MPA across cancer cell lines available in DepMap43 (Figures S5A and S5F).