Here, we show that jumonji domain modulator #7 (JDM‐7) suppressed the colony‐forming units (CFU) of leukemia cells in semi‐solid methylcellulose culture, acting as a new potential JMJD1C modulator, whereas, at a similar concentration in suspension culture, JDM‐7 showed no significant inhibition of the growth of leukemia cells. The gene discussed is JMJD1C; the disease is leukemia.