Although we observed a dose‐dependent reduction in BrdU incorporation in vitro in GICs that had survived a 24‐h prazosin exposure, and a decrease in Ki67 staining in tumor grafts of prazosin‐treated mice (Fig EV3A and B), no change was observed in cyclin D1, cyclin D3, and CDK2 levels, which are required for G1/S transition (Fig EV3C). The gene discussed is CCND1; the disease is neoplasm.