Objectives: To assess the feasibility of using a novel ultrasensitive bright-field in situ hybridization approach (BRISH) to evaluate κ and λ immunoglobulin messenger RNA (mRNA) expression in situ in B-cell non-Hodgkin lymphoma (NHL).
Methods: A series of 110 semiconsecutive clinical cases evaluated for lymphoma with historic flow cytometric (FCM) results were assessed with BRISH.
Results: BRISH light chain restriction (LCR) results were concordant with FCM in 108 (99%) of 109 evaluable cases. Additional small B-cell lymphoma cohorts were successfully evaluated.
Conclusions: BRISH analysis of κ and λ immunoglobulin mRNA expression is a sensitive tool for establishing LCR in B-cell NHL when FCM results are not available.
Keywords: B-cell clonality; B-cell lymphoma; BRISH; CISH; In situ hybridization; RNAscope.