YTHDF2-IN-1 (Compound CK-75) is an inhibitor of YT521-B homology domain family 2 (YTHDF2) with a dissociation constant (Kd) of 26.2 μM, and it effectively blocks the interaction between YTHDF2 and m6A RNA. It suppresses colony formation in JAR cells and exhibits antiproliferative activity in various cancer cell lines, with an IC50 in the micromolar range. Additionally, YTHDF2-IN-1 induces apoptosis in K562 cells and causes cell cycle arrest at the G0/G1 phase.