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). Here, IMPDH2 is linked to cancer.