Heterozygous point mutations of EZH2 occurring at tyrosine 641 (Y641) within the C-terminal catalytic SET domain of EZH2 are observed in 22% of germinal center B-cell (GCB) diffuse large B-cell lymphomas (DLBCL) and 7%—12% of follicular lymphomas (FL), and contribute to EZH2’s oncogenic potential. Here, EZH2 is linked to follicular lymphoma.