ACVR1 and lymphoma: This expression pattern of ACVR1 showed a negative correlation with the high expression and activity of PRC2 in germinal center B cell (Figure S2B, Supporting Information).[19, 20] In our expanded lymphoma panel, WSU‐DLCL2, Karpas422 and SU‐DHL‐4 carry the EZH2‐GoF mutations and are sensitive to PRC2 inhibition, while Toledo, OCI‐Ly19 and SU‐DHL‐1 do not and the H3K27me3 at ACVR1 was lower in them (Figure S2C,D, Supporting Information).