As of November 17, 2025, the Cancer Genetics and Genomics Laboratory (CGL) at BC Cancer is offering LExA gene expression profiling assay for diffuse large B-cell lymphomas and high grade B-cell lymphomas and will be available to all pathologists across the province for ordering.
The LExA assay is used to identify tumour cell-of-origin and the dark zone signature, both of which have prognostic and predictive utility. The LExA assay can also identify a signature that can discriminate primary mediastinal large B-cell lymphoma from diffuse large B-cell lymphoma NOS in the correct clinical setting.
LExA will replace FISH as the first-tier test for all diffuse large B-cell lymphomas and high grade B-cell lymphomas. FISH for MYC and BCL2 will be performed as a reflex test on any case that is dark zone positive or indeterminant by LExA or any cases that fails to provide an interpretable result by LExA. Additional information can be found in our memo. Further details, including methods and testing requirements, for LExA can be found here, and High Grade B-Cell Lymphoma can be found here.
The LExA assay can be ordered using the CGL Lymphoma Requisition found on our Requisitions page.