Abundant expression of BMI1 in follicular lymphoma is associated with reduced overall survival

Abstract

Although generally indolent, follicular lymphoma (FL) sometimes pursues a more aggressive course leading to early death. B-cell-specific Mo-MLV insertion site-1 (BMI1) is a member of the polycomb group (PcG) proteins that confer stem cell properties through gene silencing. We used multi-channel immunofluorescence and automated image analysis to quantify BMI1 selectively in the nuclei of FL-derived B-cells in routine biopsy specimens. Applying this assay to 109 pretreatment FL biopsy samples demonstrates a significant association between abundant BMI1 and reduced overall survival (p = .001); the statistically significant association with mortality persists in a Cox proportional hazards model that includes Follicular Lymphoma International Prognostic Index (FLIPI) score, histological grade, and the presence of a component of diffuse large B-cell lymphoma in the biopsy sample. Ascertaining BMI1 over-expression may be useful in identifying patients who might benefit from novel therapies directed at reversing the chromatin-modifying functions of BMI1.

Keywords:

• Follicular lymphoma
• BMI1
• immunofluorescence
• prognosis
• image analysis

Acknowledgements

The authors gratefully acknowledge technical assistance provided by Lee Boudreau of the Queen's Laboratory for Molecular Pathology. M. Alhejaily received a studentship from King Fahad Medical City (KFMC) through the Saudi Arabian Cultural Bureau, Ottawa, Canada. This work was also supported by a grant from the Leukemia and Lymphoma Society of Canada to D. P. LeBrun.

Potential conflict of interest

Disclosure forms provided by the authors are available with the full text of this article online at https://doi.org/10.1080/10428194.2017.1410883.