Chromogenic LMO2 mRNA ISH Expression Correlates with LMO2 Protein and Gene Expression and Captures Their Survival Impact in Diffuse Large B-Cell Lymphoma, NOS.

Simple Summary: In this study, our primary aim was to evaluate LMO2 mRNA expression in tissue, an area with limited research. Studies assessing LMO2 mRNA expression overlook tissue morphology since they have relied on microarray platforms or PCR methods. Our results show a reliable method to identify LMO2 mRNA expression in tissues, capturing the reported biologic features of LMO2, that may be useful to study LMO2 mRNA expression in hematological neoplasms and solid tumors. Background: LMO2 is a relevant gene involved in B-cell ontogeny and a survival predictor of aggressive large B-cell lymphomas (aLBCL). Most studies assessing LMO2 mRNA expression have relied on microarray platforms or qRT-PCR methods, overlooking tissue morphology. In this study, we evaluate LMO2 RNA expression by chromogenic in situ hybridization (CISH) in normal tissue and in a series of 82 aLBCL. Methods: LMO2 CISH was performed in formalin-fixed paraffin-embedded tissues, scored by three different methods, and correlated with a transcriptome panel. Results: We obtained statistically significant results correlating the methods of evaluation with LMO2 protein expression and gene expression results. Normal tonsil tissue showed high levels of LMO2, particularly within the light zone of the germinal center. Conversely, in aLBCL, a notable reduction in LMO2 expression was noted, remarkably in cases carrying MYC rearrangements. Furthermore, significant results were obtained through overall survival and Cox regression survival analysis, incorporating International Prognostic Index data alongside LMO2 expression levels. Conclusions: We show a reliable method to identify LMO2 mRNA expression by CISH, effectively capturing many of the reported biologic features of LMO2. [ABSTRACT FROM AUTHOR]